handle POUs with no VAR .. END_VAR blocks

fix bug introduced in previous commit (matiec was unable to parse SFC code)

Fix tracking of line numbers in IL code (error messages were previously indicating incorrect line number).

Fix bug in datatype narrowing algorithm affecting IL code.

Set the symbol->token member in symbolic_variables_c objects.

Debugging helper class: print value of tokens in debugging output.

Fix bug: allow global variables of type DT (initial values for DT are not const!)

Add comment stating how to enable debug option in flex.

merge

Print error message when FB/Struct initial value contains other strcuts/FB/arrays (not yet supported by C code generator).

Do datatype checking of initial values for structures and FBs, and print error messages when compiling erroneuos source code.

fix bug in symbol_c::find_element()

Acceept structure_element_declaration_c symbol as a possible (non base type) data type

Add token references in structure_element_declaration_c

Add token reference to all symbol_c, and add list_c::find_element()

remove debug code left in by mistake in previous commit

Access elements[] in list_c through a new get_element() method.

Start implementation of datatype checking of initial values for structures and FBs.

fix wrong common_ticktime if task interval is greater than 4.3 seconds

Allow use of GLOBAL/EXTERNAL variables as control variable of FOR loop.

Start adding support for explicit initialization of FB instances. Currently only allows initializing FB variables of elementary types.

merge

merge

merge

Fix date conversion function (seconds to Date_and_Time). First day of month was falling on previous month.

Fix error locations messed up in previous commit.

fix compilation of SFC transitions written in IL (compiler was entering endless loop)

fix SFC timed qualifier (D, L, ...) with variable time (was generating wrong C code)

Fix segmentation fault bug introduced by previous commit

Correcty determine the datatype (TIME) of the parameters of SFC actions with timed qualifiers

Check that flex is installed during ./configure

Fix code generation for XOR expressions in ST (add parenthesis)

merge

make autogenerated functions to be 'static inline' instead of 'inline'

This fixes link issue and compile warning, for more details about this
issue look at
https://bitbucket.org/mjsousa/matiec/issues/53/c-compiler-warning-if-iec-function-is-used

Merged mjsousa/matiec into default

merge

Merged mjsousa/matiec into default

fix bug introduced by commit 91bef6704b44 (parsing SFCs with transitions in ST and leading whitespace => endless loop)

Only allow function invocation outside ST expressions when command line option is activated.

Ignore pragmas inside IL code when handling inline function calls.

Fix bug: correctly handle formal function calls in IL with no parameters.

Add support for functions returning VOID (i.e. non-standard extension, allowing functions that do not return any data)

Add -warn flag when running flex -> warn of potential bugs

Add support for non-standard VOID datatype. May ony be used to define functions returning VOID.

Delete the YY_NO_UNPUT define, as we do use the unput() function.

Add support for non standard feature: allow POUs with no in, out and inout parameters

Add option to not add the EN and ENO parameters to every function and FB (generated C code becomes smaller, and uses less memory for function invocations)

Correctly identify errors when parsing erroneous code (make sure flex goes back to INITIAL state when code contains errors that do not allow determining whether ST or IL is being parsed)