--- a/stage1_2/iec_flex.ll Wed May 09 22:59:10 2012 +0100
+++ b/stage1_2/iec_flex.ll Wed May 09 23:00:10 2012 +0100
@@ -91,8 +91,10 @@
*/
%option noyy_top_state
-/* We will not be using unput() in our flex code... */
+/* We will be using unput() in our flex code, so we cannot set the following option!... */
+/*
%option nounput
+*/
/**************************************************/
/* External Variable and Function declarations... */
@@ -241,6 +243,10 @@
%{
/* return all the text in the current token back to the input stream. */
void unput_text(unsigned int n);
+/* return all the text in the current token back to the input stream,
+ * but first return to the stream an additional character to mark the end of the token.
+ */
+void unput_and_mark(const char c);
%}
@@ -340,6 +346,16 @@
* expecting any action qualifiers, flex does not return these tokens, and is free
* to interpret them as previously defined variables/functions/... as the case may be.
*
+ * The time_literal_state is required because TIME# literals are decomposed into
+ * portions, and wewant to send these portions one by one to bison. Each poertion will
+ * represent the value in days/hours/minutes/seconds/ms.
+ * Unfortunately, some of these portions may also be lexically analysed as an identifier. So,
+ * we need to disable lexical identification of identifiers while parsing TIME# literals!
+ * e.g.: TIME#55d_4h_56m
+ * We would like to return to bison the tokens 'TIME' '#' '55d' '_' '4h' '_' '56m'
+ * Unfortunately, flex will join '_' and '4h' to create a legal {identifier} '_4h',
+ * and return that identifier instead! So, we added this state!
+ *
* The state machine has 7 possible states (INITIAL, config, decl, body, st, il, sfc)
* Possible state changes are:
* INITIAL -> goto(decl_state)
@@ -418,7 +434,8 @@
/* we are parsing sfc code, and expecting the priority token. */
%s sfc_priority_state
-
+/* we are parsing a TIME# literal. We must not return any {identifier} tokens. */
+%x time_literal_state
/*******************/
@@ -598,6 +615,15 @@
/* B.1.2.1 Numeric literals */
/******************************/
integer {digit}((_?{digit})*)
+
+/* Some helper symbols for parsing TIME literals... */
+integer_0_59 (0(_?))*([0-5](_?))?{digit}
+integer_0_19 (0(_?))*([0-1](_?))?{digit}
+integer_20_23 (0(_?))*2(_?)[0-3]
+integer_0_23 {integer_0_19}|{integer_20_23}
+integer_0_999 {digit}((_?{digit})?)((_?{digit})?)
+
+
binary_integer 2#{bit}((_?{bit})*)
bit [0-1]
octal_integer 8#{octal_digit}((_?{octal_digit})*)
@@ -673,21 +699,54 @@
/************************/
fixed_point {integer}\.{integer}
-fixed_point_d {fixed_point}d
-integer_d {integer}d
-
-fixed_point_h {fixed_point}h
-integer_h {integer}h
-
-fixed_point_m {fixed_point}m
-integer_m {integer}m
-
-fixed_point_s {fixed_point}s
-integer_s {integer}s
-
-fixed_point_ms {fixed_point}ms
-integer_ms {integer}ms
-
+
+/* NOTE: The IEC 61131-3 v2 standard has an incorrect formal syntax definition of duration,
+ * as its definition does not match the standard's text.
+ * IEC 61131-3 v3 (committee draft) seems to have this fixed, so we use that
+ * definition instead!
+ *
+ * duration::= ('T' | 'TIME') '#' ['+'|'-'] interval
+ * interval::= days | hours | minutes | seconds | milliseconds
+ * fixed_point ::= integer [ '.' integer]
+ * days ::= fixed_point 'd' | integer 'd' ['_'] [ hours ]
+ * hours ::= fixed_point 'h' | integer 'h' ['_'] [ minutes ]
+ * minutes ::= fixed_point 'm' | integer 'm' ['_'] [ seconds ]
+ * seconds ::= fixed_point 's' | integer 's' ['_'] [ milliseconds ]
+ * milliseconds ::= fixed_point 'ms'
+ *
+ *
+ * The original IEC 61131-3 v2 definition is:
+ * duration ::= ('T' | 'TIME') '#' ['-'] interval
+ * interval ::= days | hours | minutes | seconds | milliseconds
+ * fixed_point ::= integer [ '.' integer]
+ * days ::= fixed_point 'd' | integer 'd' ['_'] hours
+ * hours ::= fixed_point 'h' | integer 'h' ['_'] minutes
+ * minutes ::= fixed_point 'm' | integer 'm' ['_'] seconds
+ * seconds ::= fixed_point 's' | integer 's' ['_'] milliseconds
+ * milliseconds ::= fixed_point 'ms'
+
+ */
+
+interval_ms_X ({integer_0_999}(\.{integer})?)ms
+interval_s_X {integer_0_59}s(_?{interval_ms_X})?
+interval_m_X {integer_0_59}m(_?{interval_s_X})?
+interval_h_X {integer_0_23}h(_?{interval_m_X})?
+
+interval_ms {integer}ms|({fixed_point}ms)
+interval_s {integer}s(_?{interval_ms_X})?|({fixed_point}s)
+interval_m {integer}m(_?{interval_s_X})?|({fixed_point}m)
+interval_h {integer}h(_?{interval_m_X})?|({fixed_point}h)
+interval_d {integer}d(_?{interval_h_X})?|({fixed_point}d)
+
+interval {interval_ms}|{interval_s}|{interval_m}|{interval_h}|{interval_d}
+
+/* to help provide nice error messages, we also parse an incorrect but plausible interval... */
+/* NOTE that this erroneous interval will be parsed outside the time_literal_state, so must not
+ * be able to parse any other legal lexcial construct (besides a legal interval, but that
+ * is OK as this rule will appear _after_ the rule to parse legal intervals!).
+ */
+fixed_point_or_integer {fixed_point}|{integer}
+erroneous_interval ({fixed_point_or_integer}d_?)?({fixed_point_or_integer}h_?)?({fixed_point_or_integer}m_?)?({fixed_point_or_integer}s_?)?({fixed_point_or_integer}ms)?
/********************************************/
/* B.1.4.1 Directly Represented Variables */
@@ -719,9 +778,9 @@
* in which case we are currently using "%I3" as the variable
* name.
*/
-direct_variable_matplc %{identifier}
-
-direct_variable {direct_variable_standard}|{direct_variable_matplc}
+/* direct_variable_matplc %{identifier} */
+/* direct_variable {direct_variable_standard}|{direct_variable_matplc} */
+direct_variable {direct_variable_standard}
/******************************************/
/* B 1.4.3 - Declaration & Initialisation */
@@ -1541,23 +1600,26 @@
/* B 1.2.3.1 - Duration */
/************************/
{fixed_point} {yylval.ID=strdup(yytext); return fixed_point_token;}
-
-{fixed_point_d} {yylval.ID=strdup(yytext); yylval.ID[yyleng-1] = '\0'; return fixed_point_d_token;}
-{integer_d} {yylval.ID=strdup(yytext); yylval.ID[yyleng-1] = '\0'; return integer_d_token;}
-
-{fixed_point_h} {yylval.ID=strdup(yytext); yylval.ID[yyleng-1] = '\0'; return fixed_point_h_token;}
-{integer_h} {yylval.ID=strdup(yytext); yylval.ID[yyleng-1] = '\0'; return integer_h_token;}
-
-{fixed_point_m} {yylval.ID=strdup(yytext); yylval.ID[yyleng-1] = '\0'; return fixed_point_m_token;}
-{integer_m} {yylval.ID=strdup(yytext); yylval.ID[yyleng-1] = '\0'; return integer_m_token;}
-
-{fixed_point_s} {yylval.ID=strdup(yytext); yylval.ID[yyleng-1] = '\0'; return fixed_point_s_token;}
-{integer_s} {yylval.ID=strdup(yytext); yylval.ID[yyleng-1] = '\0'; return integer_s_token;}
-
-{fixed_point_ms} {yylval.ID=strdup(yytext); yylval.ID[yyleng-2] = '\0'; return fixed_point_ms_token;}
-{integer_ms} {yylval.ID=strdup(yytext); yylval.ID[yyleng-2] = '\0'; return integer_ms_token;}
-
-
+{interval} {/*fprintf(stderr, "entering time_literal_state ##%s##\n", yytext);*/ unput_and_mark('#'); yy_push_state(time_literal_state);}
+{erroneous_interval} {return erroneous_interval_token;}
+
+<time_literal_state>{
+{integer}d {yylval.ID=strdup(yytext); yylval.ID[yyleng-1] = '\0'; return integer_d_token;}
+{integer}h {yylval.ID=strdup(yytext); yylval.ID[yyleng-1] = '\0'; return integer_h_token;}
+{integer}m {yylval.ID=strdup(yytext); yylval.ID[yyleng-1] = '\0'; return integer_m_token;}
+{integer}s {yylval.ID=strdup(yytext); yylval.ID[yyleng-1] = '\0'; return integer_s_token;}
+{integer}ms {yylval.ID=strdup(yytext); yylval.ID[yyleng-2] = '\0'; return integer_ms_token;}
+{fixed_point}d {yylval.ID=strdup(yytext); yylval.ID[yyleng-1] = '\0'; return fixed_point_d_token;}
+{fixed_point}h {yylval.ID=strdup(yytext); yylval.ID[yyleng-1] = '\0'; return fixed_point_h_token;}
+{fixed_point}m {yylval.ID=strdup(yytext); yylval.ID[yyleng-1] = '\0'; return fixed_point_m_token;}
+{fixed_point}s {yylval.ID=strdup(yytext); yylval.ID[yyleng-1] = '\0'; return fixed_point_s_token;}
+{fixed_point}ms {yylval.ID=strdup(yytext); yylval.ID[yyleng-2] = '\0'; return fixed_point_ms_token;}
+
+_ /* do nothing - eat it up!*/
+\# {/*fprintf(stderr, "poping from time_literal_state (###)\n");*/ yy_pop_state(); return end_interval_token;}
+. {ERROR;}
+\n {ERROR;}
+}
/*******************************/
/* B.1.2.2 Character Strings */
/*******************************/
@@ -1645,6 +1707,20 @@
}
+/* return all the text in the current token back to the input stream,
+ * but first return to the stream an additional character to mark the end of the token.
+ */
+void unput_and_mark(const char c) {
+ char *yycopy = strdup( yytext ); /* unput() destroys yytext, so we copy it first */
+ unput(c);
+ for (int i = yyleng-1; i >= 0; i--)
+ unput(yycopy[i]);
+
+ free(yycopy);
+}
+
+
+
/* Called by flex when it reaches the end-of-file */
int yywrap(void)
{