ack/lang/m2/comp/expression.g
1986-04-03 00:44:39 +00:00

162 lines
2.3 KiB
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/* E X P R E S S I O N S */
{
static char *RcsId = "$Header$";
#include <alloc.h>
#include <em_arith.h>
#include <em_label.h>
#include "LLlex.h"
#include "idf.h"
#include "def.h"
#include "scope.h"
}
number:
INTEGER
|
REAL
;
qualident(int types; struct def **pdf; char *str;)
{
int scope;
int module;
register struct def *df;
struct def *lookfor();
} :
IDENT { if (types) {
df = lookfor(dot.TOK_IDF, CurrentScope, 1);
*pdf = df;
if (df->df_kind == D_ERROR) types = 0;
}
}
[
{ if (types &&!(scope = has_selectors(df))) {
types = 0;
*pdf = ill_df;
}
}
/* selector */
'.' IDENT
{ if (types) {
module = (df->df_kind == D_MODULE);
df = lookup(dot.TOK_IDF, scope);
if (!df) {
error("identifier \"%s\" not declared",
dot.TOK_IDF->id_text);
types = 0;
df = ill_df;
}
else
if (module &&
!(df->df_flags&(D_EXPORTED|D_QEXPORTED))) {
error("identifier \"%s\" not exported from qualifying module", dot.TOK_IDF->id_text);
}
}
}
]*
{ if (types && !(types & df->df_kind)) {
error("identifier \"%s\" is not a %s",
df->df_idf->id_text, str);
}
}
;
selector:
'.' /* field */ IDENT
;
ExpList:
expression [ ',' expression ]*
;
ConstExpression:
expression
/*
* Changed rule in new Modula-2.
* Check that the expression is a constant expression and evaluate!
*/
;
expression:
SimpleExpression [ relation SimpleExpression ]?
;
relation:
'=' | '#' | UNEQUAL | '<' | LESSEQUAL | '>' | GREATEREQUAL | IN
;
SimpleExpression:
[ '+' | '-' ]? term [ AddOperator term ]*
;
AddOperator:
'+' | '-' | OR
;
term:
factor [ MulOperator factor ]*
;
MulOperator:
'*' | '/' | DIV | MOD | AND | '&'
;
factor
{
struct def *df;
} :
qualident(0, &df, (char *) 0)
[
designator_tail? ActualParameters?
|
bare_set
]
|
bare_set
| %default
number
|
STRING
|
'(' expression ')'
|
NOT factor
;
bare_set:
'{' [ element [ ',' element ]* ]? '}'
;
ActualParameters:
'(' ExpList? ')'
;
element:
expression [ UPTO expression ]?
;
designator
{
struct def *df;
} :
qualident(0, &df, (char *) 0)
designator_tail?
;
designator_tail:
visible_designator_tail
[
selector
|
visible_designator_tail
]*
;
visible_designator_tail:
'[' ExpList ']'
|
'^'
;