readme
author Mario de Sousa <msousa@fe.up.pt>
Fri, 10 Feb 2012 19:04:31 +0000
changeset 438 744b125d911e
parent 265 4d222f46f8cc
child 444 92d40d2a7adc
permissions -rwxr-xr-x
Add support for semantic verification of function calls in IL.
0
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
     1
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
     2
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
     3
265
4d222f46f8cc Updating license info (with Edouard's permission for relevant files).
Mario de Sousa <msousa@fe.up.pt>
parents: 67
diff changeset
     4
  MATIEC - IEC 61131-3 compiler
0
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
     5
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
     6
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
     7
  The following compiler has been based on the
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
     8
  FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
     9
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    10
265
4d222f46f8cc Updating license info (with Edouard's permission for relevant files).
Mario de Sousa <msousa@fe.up.pt>
parents: 67
diff changeset
    11
  Copyright (C) 2003-2011  Mario de Sousa (msousa@fe.up.pt)
0
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    12
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    13
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    14
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    15
****************************************************************
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    16
****************************************************************
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    17
****************************************************************
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    18
*********                                              *********
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    19
*********                                              *********
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    20
*********   O V E R A L L    A R C H I T E C T U R E   *********
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    21
*********                                              *********
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    22
*********                                              *********
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    23
****************************************************************
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    24
****************************************************************
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    25
****************************************************************
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    26
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    27
 The compiler works in 4(+1) stages:
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    28
 Stage 1   - Lexical analyser      - implemented with flex (iec.flex)
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    29
 Stage 2   - Syntax parser         - implemented with bison (iec.y)
265
4d222f46f8cc Updating license info (with Edouard's permission for relevant files).
Mario de Sousa <msousa@fe.up.pt>
parents: 67
diff changeset
    30
 Stage 3   - Semantics analyser    - currently in its early stages
0
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    31
 Stage 4   - Code generator        - implemented in C++
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    32
 Stage 4+1 - Binary code generator - gcc, javac, etc...
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    33
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    34
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    35
 Data structures passed between stages, in global variables:
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    36
 1->2   : tokens (int), and token values (char *)
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    37
 2->1   : symbol tables (defined in symtable.hh)
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    38
 2->3   : abstract syntax tree (tree of C++ classes, in absyntax.hh file)
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    39
 3->4   : Same as 2->3
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    40
 4->4+1 : file with program in c, java, etc...
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    41
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    42
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    43
 The compiler works in several passes:
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    44
 Pass 1: executes stages 1 and 2 simultaneously
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    45
 Pass 2: executes stage 3
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    46
 Pass 3: executes stage 4
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    47
 Pass 4: executes stage 4+1
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    48
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    49
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    50
 NOTE 1
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    51
 ======
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    52
 Note that stage 2 passes data back to stage 1. This is only
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    53
possible because both stages are executed in the same pass.
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    54
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    55
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    56
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    57
 NOTE 2
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    58
 ======
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    59
 It would be nice to get this parser integrated into the gcc
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    60
group of compilers. We would then be able to compile our st/il
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    61
programs directly into executable binaries, for all the processor
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    62
architectures gcc currently supports.
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    63
 The gcc compilers are divided into a frontend and backend. The
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    64
data structure between these two stages is called the syntax
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    65
tree. In essence, we would need to create a new frontend that
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    66
would parse the st/il program and build the syntax tree.
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    67
Unfortunately the gcc syntax tree is not very well documented,
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    68
and doing semantic checking on this tree would probably be a
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    69
nightmare.
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    70
 We therefore chose to follow the same route as the gnat (ada 95)
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    71
and cobol compilers, i.e. generate our own abstract syntax tree,
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    72
do semantic checking on our tree, do whatever optimisation
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    73
we can at this level on our own tree, and only then build
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    74
the gcc syntax tree from our abstract syntax tree.
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    75
 All this may still be integrated with the gcc backend to generate
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    76
a new gnu compiler for the st and il programming languages.
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    77
Since generating the gcc syntax tree will probably envolve some
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    78
trial and error effort due to the sparseness of documentation,
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    79
we chose to start off by coding a C++ code generator for
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    80
our stage 4. We may later implement a gcc syntax tree generator
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    81
as an alternative stage 4 process, and then integrate it with
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    82
the gcc toplevel.c file (command line parsing, etc...).
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    83
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    84
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    85
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    86
****************************************************************
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    87
****************************************************************
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    88
****************************************************************
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    89
*********                                              *********
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    90
*********                                              *********
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    91
*********               S T A G E      1               *********
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    92
*********                                              *********
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    93
*********                                              *********
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    94
****************************************************************
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    95
****************************************************************
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    96
****************************************************************
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    97
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    98
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
    99
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   100
Issue 1
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   101
=======
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   102
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   103
 The syntax defines the common_character_representation as:
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   104
<any printable character except '$', '"' or "'"> | <escape sequences>
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   105
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   106
 Flex includes the function print_char() that defines
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   107
all printable characters portably (i.e. whatever character
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   108
encoding is currently being used , ASCII, EBCDIC, etc...)
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   109
Unfortunately, we cannot generate the definition of
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   110
common_character_representation portably, since flex
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   111
does not allow definition of sets by subtracting
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   112
elements in one set from another set (Note how
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   113
common_character_representation could be defined by
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   114
subtracting '$' '"' and "'" from print_char() ).
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   115
This means we must build up the defintion of
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   116
common_character_representation using only set addition,
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   117
which leaves us with the only choice of defining the
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   118
characters non-portably...
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   119
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   120
 In short, the definition we use for common_character_representation
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   121
only works for ASCII character encoding!
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   122
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   123
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   124
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   125
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   126
Issue 2
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   127
=======
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   128
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   129
We extend the IEC 61131-3 standard syntax to allow inclusion of 
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   130
other files. The accepted syntax is:
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   131
265
4d222f46f8cc Updating license info (with Edouard's permission for relevant files).
Mario de Sousa <msousa@fe.up.pt>
parents: 67
diff changeset
   132
   {#include "<filename>" }
4d222f46f8cc Updating license info (with Edouard's permission for relevant files).
Mario de Sousa <msousa@fe.up.pt>
parents: 67
diff changeset
   133
4d222f46f8cc Updating license info (with Edouard's permission for relevant files).
Mario de Sousa <msousa@fe.up.pt>
parents: 67
diff changeset
   134
We use a pragma directive for this (allowed by the standard itself),
4d222f46f8cc Updating license info (with Edouard's permission for relevant files).
Mario de Sousa <msousa@fe.up.pt>
parents: 67
diff changeset
   135
 since it is an extension of the standard. In principle, this would 
4d222f46f8cc Updating license info (with Edouard's permission for relevant files).
Mario de Sousa <msousa@fe.up.pt>
parents: 67
diff changeset
   136
be ignored by other standard complient compilers!
0
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   137
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   138
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   139
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   140
****************************************************************
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   141
****************************************************************
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   142
****************************************************************
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   143
*********                                              *********
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   144
*********                                              *********
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   145
*********               S T A G E      2               *********
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   146
*********                                              *********
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   147
*********                                              *********
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   148
****************************************************************
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   149
****************************************************************
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   150
****************************************************************
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   151
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   152
 Overall Comments
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   153
 ================
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   154
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   155
 
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   156
 Comment 1
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   157
 ---------
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   158
 We have augmented the syntax the specification defines to include
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   159
restrictions defined in the semantics of the languages.
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   160
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   161
 This is required because the syntax cannot be parsed by a LALR(1)
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   162
parser as it is presented in the specification. Many reduce/reduce
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   163
and shift/reduce conflicts arise. This is mainly because the parser
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   164
cannot discern how to reduce an identifier. Identifiers show up in
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   165
many places in the syntax, and it is not entirely possible to
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   166
figure out if the identifier is a variable_name, enumeration
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   167
value, function block name, etc... only from the context in
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   168
which it appears.
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   169
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   170
 A more detailed example of why we need symbol tables are
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   171
the type definitions...  In definition of new types
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   172
(section B 1.3.3) the parser needs to figure out the class of
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   173
the new type being defined (enumerated, structure, array, etc...).
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   174
This works well when the base classes are elementary types
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   175
(or structures, enumeration, arrays, etc. thereof). It becomes
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   176
confusing to the parser when the new_type is based on a previously
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   177
user defined type.
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   178
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   179
TYPE
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   180
  new_type_1 : INT := 99;
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   181
  new_type_2 : new_type_1 := 100;
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   182
END_TYPE
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   183
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   184
 When parsing new_type_1, the parser can figure out that the
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   185
identifier new_type_1 is a simple_type_name, because it is
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   186
based on a elementary type without structure, arrays, etc...
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   187
 While parsing new_type_2, it becomes confused how to reduce
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   188
the new_type_2 identifier, as it is based on the identifier
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   189
new_type_1, of which it does not know the class (remember, at this
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   190
stage new_type_1 is a simple identifier!).
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   191
 We therefore need to keep track of the class of the user
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   192
defined types as they are declared, so that the lexical analyser
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   193
can tell the syntax parser what class the type belongs to. We
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   194
cannot use the abstract syntax tree itself to search for the
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   195
declaration of new_type_1 as we only get a handle to the root
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   196
of the tree at the end of the parsing.
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   197
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   198
 We therefore maintain an independent and parallel table of symbols,
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   199
that is filled as we come across the type delcarations in the code.
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   200
Actually, we ended up also needing to store variable names in
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   201
the symbol table. Since variable names come and go out of scope
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   202
depending on what portion of code we are parsing, we sometimes
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   203
need to remove the variable names from the symbol table.
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   204
Since the ST and IL languages only have a single level of scope,
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   205
I (Mario) found it easier to simply use a second symbol table for
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   206
the variable names that is completely cleared when the parser
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   207
reaches the end of a function (function block or program).
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   208
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   209
What I mean when I say that these languages have a single level
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   210
of scope is that all variables used in a function (function block
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   211
or program) must be declared inside that function (function block
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   212
or program). Even global variables must be re-declared as EXTERN
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   213
before a function may access them! This means that it is easy
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   214
to simply load up the variable name symbol table when we start
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   215
parsing a function (function block or program), and to clear it
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   216
when we reach the end. Checking whether variables declared
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   217
as EXTERN really exist inside a RESOURCE or a CONFIGURATION
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   218
is left to stage 3 (semantic checking) where we can use the
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   219
abstract tree itself to search for the variables (NOTE: semantic
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   220
cheching at stage 3 has not yet been implemented, so we may yet
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   221
end up using a symbol table too at that stage!).
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   222
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   223
 Due to the use of the symbol tables, and special identifier
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   224
tokens depending on the type of identifier it had previously
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   225
been declared in the code being parsed, the syntax was slightly
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   226
changed regarding the definition of variable names, derived
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   227
function names, etc... FROM for e.g.:
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   228
variable_name: identifier;
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   229
TO
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   230
variable_name: variable_name_token;
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   231
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   232
 Flex first looks at the symbol tables when it finds an identifier,
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   233
and returns the correct token corresponding to the identifier
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   234
type in question. Only if the identifier is not currently stored
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   235
in any symbol table, does flex return a simple identifier_token.
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   236
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   237
 This means that the declarations of variables, functions etc...
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   238
were changed FROM:
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   239
function_declaration: FUNCTION derived_function_name ...
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   240
TO
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   241
function_declaration: FUNCTION identifier ...
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   242
since the initial definition of derived_function_name had been
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   243
changed FROM
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   244
derived_function_name: identifier;
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   245
TO
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   246
derived_function_name: derived_function_name_token;
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   247
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   248
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   249
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   250
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   251
 Comment 2
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   252
 ---------
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   253
 Since the ST and IL languages share a lot of common syntax,
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   254
I have decided to write a single parser to handle both languages
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   255
simultaneously. This approach has the advantage that the user
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   256
may mix the language used in the same file, as long as each function
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   257
is written in a single lanuage.
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   258
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   259
 This approach also assumes that all the IL language operators are
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   260
keywords, which means that it is not possible to define variables
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   261
using names such as "LD", "ST", etc...
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   262
Note that the spec does not consider these operators to be keywords,
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   263
so it means that they should be available for variable names! On the
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   264
other hand, all implementations of the ST and IL languages seems to
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   265
treat them as keywords, so there is not much harm in doing the same.
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   266
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   267
 If it ever becomes necessary to allow variables with names of IL 
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   268
operators, either the syntax will have to be augmented, or we can 
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   269
brake up the parser in two: one for ST and another for IL.
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   270
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   271
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   272
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   273
/********************************/
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   274
/* B 1.3.3 - Derived data types */
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   275
/********************************/
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   276
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   277
Issue 1
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   278
=======
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   279
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   280
According to the spec, the valid construct
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   281
TYPE new_str_type : STRING := "hello!"; END_TYPE
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   282
has two possible routes to type_declaration...
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   283
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   284
Route 1:
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   285
type_declaration: single_element_type_declaration
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   286
single_element_type_declaration: simple_type_declaration
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   287
simple_type_declaration: identifier ':' simple_spec_init
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   288
simple_spec_init: simple_specification ASSIGN constant
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   289
(shift:  identifier <- 'new_str_type')
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   290
simple_specification: elementary_type_name
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   291
elementary_type_name: STRING
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   292
(shift: elementary_type_name <- STRING)
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   293
(reduce: simple_specification <- elementary_type_name)
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   294
(shift: constant <- "hello!")
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   295
(reduce: simple_spec_init: simple_specification ASSIGN constant)
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   296
(reduce: ...)
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   297
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   298
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   299
Route 2:
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   300
type_declaration: string_type_declaration
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   301
string_type_declaration: identifier ':' elementary_string_type_name string_type_declaration_size string_type_declaration_init
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   302
(shift:  identifier <- 'new_str_type')
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   303
elementary_string_type_name: STRING
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   304
(shift: elementary_string_type_name <- STRING)
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   305
(shift: string_type_declaration_size <- /* empty */)
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   306
string_type_declaration_init: ASSIGN character_string
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   307
(shift: character_string <- "hello!")
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   308
(reduce: string_type_declaration_init <- ASSIGN character_string)
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   309
(reduce: string_type_declaration <- identifier ':' elementary_string_type_name string_type_declaration_size string_type_declaration_init )
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   310
(reduce: type_declaration <- string_type_declaration)
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   311
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   312
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   313
 At first glance it seems that removing route 1 would make
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   314
the most sense. Unfortunately the construct 'simple_spec_init'
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   315
shows up multiple times in other rules, so changing this construct
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   316
would mean changing all the rules in which it appears.
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   317
I (Mario) therefore chose to remove route 2 instead. This means
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   318
that the above declaration gets stored in a
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   319
simple_type_declaration_c, and not in a string_type_declaration_c
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   320
as would be expected!
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   321
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   322
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   323
/***********************/
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   324
/* B 1.5.1 - Functions */
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   325
/***********************/
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   326
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   327
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   328
Issue 1
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   329
=======
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   330
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   331
 Due to reduce/reduce conflicts between identifiers
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   332
being reduced to either a variable or an enumerator value,
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   333
we were forced to keep a symbol table of the names
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   334
of all declared variables. Variables are no longer
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   335
created from simple identifier_token, but from
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   336
variable_name_token.
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   337
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   338
 BUT, in functions the function name may be used as
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   339
a variable! In order to be able to parse this correctly,
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   340
the token parser (flex) must return a variable_name_token
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   341
when it comes across the function name, while parsing
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   342
the function itself.
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   343
We do this by inserting the function name into the variable
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   344
symbol table, and having flex return a variable_name_token
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   345
whenever it comes across it.
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   346
When we finish parsing the function the variable name
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   347
symbol table is cleared of all entries, and the function
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   348
name is inserted into the library element symbol table. This
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   349
means that from then onwards flex will return a
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   350
derived_function_name_token whenever it comes across the
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   351
function name.
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   352
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   353
In order to insert the function name into the variable_name
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   354
symbol table BEFORE the function body gets parsed, we
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   355
need the parser to reduce a construct that contains the
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   356
the function name. That is why we created the extra
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   357
construct 'function_name_declaration', i.e. to force
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   358
the parser to reduce it, before parsing the function body,
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   359
and therefore get an oportunity to insert the function name
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   360
into the variable name symbol table!
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   361
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   362
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   363
/********************************/
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   364
/* B 3.2.4 Iteration Statements */
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   365
/********************************/
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   366
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   367
Issue 1
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   368
=======
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   369
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   370
For the 'FOR' iteration loop
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   371
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   372
  FOR control_variable ASSIGN expression TO expression BY expression DO statement_list END_FOR
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   373
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   374
The spec declares the control variable in the syntax as
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   375
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   376
  control_variable: identifier;
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   377
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   378
but then defines the semantics of control_variable (Section 3.3.2.4)
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   379
as being of an integer type (e.g., SINT, INT, or DINT).
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   380
Obviously this presuposes that the control_variable must have been
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   381
declared in some 'VAR .. VAR_END' construct, so I (Mario) changed
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   382
the syntax to read
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   383
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   384
  control_variable: variable_name;
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   385
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   386
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   387
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   388
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   389
**************************************************************************
fb772792efd1 Initial commit. Last MatPLC CVS with some makefile inclusion removed in order to compile fine out of MatPLC.
etisserant
parents:
diff changeset
   390
265
4d222f46f8cc Updating license info (with Edouard's permission for relevant files).
Mario de Sousa <msousa@fe.up.pt>
parents: 67
diff changeset
   391
  Copyright (C) 2003-2011  Mario de Sousa (msousa@fe.up.pt)