}
/*
- * The parser's bias towards considering things as functions whenever possible
- * makes nested parentheses tricky. (x) is considered to be part of a function
- * declarator until simplify_functions converts it. The problem is that
- * (((x))) is not valid as part of a function declarator, but it *is* valid
- * as an identifier enclosed 3 times in parentheses. This is complicated by
- * the fact that things like (((int))) are not valid anywhere.
+ * The main parser's bias towards considering things as functions whenever
+ * possible makes nested parentheses tricky. "(x)" is considered to be part
+ * of a function declarator until simplify_functions converts it. The problem
+ * is that "(((x)))" is not valid as part of a function declarator, but it _is_
+ * valid as either an identifier enclosed thrice in parentheses, or an abstract
+ * function declarator enclosed twice in parentheses.
*
- * To avoid ambiguities, the parser actually emits a "function" declarator for
- * every pair of parentheses. The ones that can't reasonably be functions
- * consist of a single "parameter" with no declaration specifiers (note that
- * every valid function parameter will have at least one type specifier).
+ * To avoid ambiguities, the main parser actually returns a function declarator
+ * for every pair of parentheses. The ones we need to look at consist of a
+ * single parameter with an empty specifier list (noting that every real
+ * function parameter will have at least one type specifier).
*
- * This pass is to remove these fake functions from the parse tree. We take
- * care to avoid turning invalid things like ((int)) into valid things like
- * (int) by observing that the only valid function declarators that appear
- * in these "fake" parentheses are those that have a non-null child declarator
- * (for instance, int ((*)(int)) *or* those that will be eliminated by the
- * simplify_functions pass.
+ * There are two cases:
+ *
+ * - For (), the parser emits a parameter with a lone null declarator.
+ * This fake parameter simply gets deleted, leaving us with a normal
+ * function declarator with an empty identifier list.
+ *
+ * - Otherwise, the parameter's outermost declarator is not null. The
+ * function itself is deleted, replaced in the parse tree with the
+ * fake parameter's declarator.
+ *
+ * Repeating until there no fake parameters, this reduction transforms, for
+ * example, "(((x)))" into "(x)", an abstract function declarator. The result
+ * is then subject to the function simplification step, which will turn "(x)"
+ * into x (declaring an identifier).
*/
-
static struct cdecl *fake_function_param(struct cdecl_declarator *d)
{
struct cdecl *param;
reduce_parentheses(struct cdecl_declarator **p, struct cdecl_declarator *d)
{
struct cdecl *param;
- int fake = 0;
while ((param = fake_function_param(d))) {
struct cdecl_declarator *decl = param->declarators;
param->declarators = d;
*p = d = decl;
- fake = 1;
}
cdecl__free(param);
}
simplify_functions(p, d);
- if (fake && (*p)->type == CDECL_DECL_FUNCTION) {
- /* Started with a fake function but ended with a real one. */
- cdecl__errmsg(CDECL__EMANYPAREN);
- return -1;
- }
-
return 0;
}
projects / cdecl99.git / commitdiff