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Initial check-in introducing experimental GLR parsing. See entry in

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ChangeLog dated 2002-06-27 from Paul Hilfinger for details.
This commit is contained in:
Paul Hilfinger
2002-06-28 02:26:44 +00:00
parent 01241d47b4
commit 676385e29c
31 changed files with 2422 additions and 1299 deletions
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86
src/reader.c
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@@ -37,6 +37,7 @@
int lineno;
static symbol_list_t *grammar = NULL;
static int start_flag = 0;
merger_list *merge_functions;
/* Nonzero if %union has been seen. */
int typed = 0;
@@ -105,6 +106,60 @@ epilogue_set (const char *epilogue, location_t location)
/*-------------------------------------------------------------------.
| Return the merger index for a merging function named NAME, whose |
| arguments have type TYPE. Records the function, if new, in |
| merger_list. |
`-------------------------------------------------------------------*/
static int
get_merge_function (const char* name, const char* type)
{
merger_list *syms;
merger_list head;
int n;
if (! glr_parser)
return 0;
if (type == NULL)
type = "";
head.next = merge_functions;
for (syms = &head, n = 1; syms->next != NULL; syms = syms->next, n += 1)
if (strcmp (name, syms->next->name) == 0)
break;
if (syms->next == NULL) {
syms->next = XMALLOC (merger_list, 1);
syms->next->name = strdup (name);
syms->next->type = strdup (type);
syms->next->next = NULL;
merge_functions = head.next;
} else if (strcmp (type, syms->next->type) != 0)
warn (_("result type clash on merge function %s: `%s' vs. `%s'"),
name, type, syms->next->type);
return n;
}
/*--------------------------------------.
| Free all merge-function definitions. |
`--------------------------------------*/
void
free_merger_functions (void)
{
merger_list *L0;
if (! glr_parser)
return;
L0 = merge_functions;
while (L0 != NULL)
{
merger_list *L1 = L0->next;
free (L0);
L0 = L1;
}
}
/*-------------------------------------------------------------------.
| Generate a dummy symbol, a nonterminal, whose name cannot conflict |
| with the user's names. |
@@ -307,6 +362,34 @@ grammar_current_rule_prec_set (symbol_t *precsym, location_t location)
current_rule->ruleprec = precsym;
}
/* Attach dynamic precedence DPREC to the current rule. */
void
grammar_current_rule_dprec_set (int dprec, location_t location)
{
if (! glr_parser)
warn_at (location, _("%%dprec affects only GLR parsers"));
if (dprec <= 0)
complain_at (location, _("%%dprec must be followed by positive number"));
else if (current_rule->dprec != 0)
complain_at (location, _("only one %%dprec allowed per rule"));
current_rule->dprec = dprec;
}
/* Attach a merge function NAME with argument type TYPE to current
rule. */
void
grammar_current_rule_merge_set (const char* name, location_t location)
{
if (! glr_parser)
warn_at (location, _("%%merge affects only GLR parsers"));
if (current_rule->merger != 0)
complain_at (location, _("only one %%merge allowed per rule"));
current_rule->merger =
get_merge_function (name, current_rule->sym->type_name);
}
/* Attach a SYMBOL to the current rule. If needed, move the previous
action as a mid-rule action. */
@@ -319,7 +402,6 @@ grammar_current_rule_symbol_append (symbol_t *symbol, location_t location)
grammar_symbol_append (symbol, location);
}
/* Attach an ACTION to the current rule. If needed, move the previous
action as a mid-rule action. */
@@ -363,6 +445,8 @@ packgram (void)
rules[ruleno].useful = TRUE;
rules[ruleno].action = p->action;
rules[ruleno].action_location = p->action_location;
rules[ruleno].dprec = p->dprec;
rules[ruleno].merger = p->merger;
p = p->next;
while (p && p->sym)