X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/e9955c83734d0a545d7822a1feb9c4a8038a62cb..a17187e56386747a9b4d9633c3d116c2087f2b8b:/src/reader.c
diff --git a/src/reader.c b/src/reader.c
index 9e93cab6..2e0aa5ee 100644
--- a/src/reader.c
+++ b/src/reader.c
@@ -1,179 +1,159 @@
-/* Input parser for bison
- Copyright (C) 1984, 1986, 1989, 1992, 1998, 2000, 2001, 2002
- Free Software Foundation, Inc.
+/* Input parser for Bison
+
+ Copyright (C) 1984, 1986, 1989, 1992, 1998, 2000-2003, 2005-2007,
+ 2009-2012 Free Software Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
- Bison is free software; you can redistribute it and/or modify
+ This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2, or (at your option)
- any later version.
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
- Bison is distributed in the hope that it will be useful,
+ This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
- along with Bison; see the file COPYING. If not, write to
- the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA. */
-
+ along with this program. If not, see . */
+#include
#include "system.h"
-#include "quotearg.h"
-#include "quote.h"
-#include "getargs.h"
+
+#include
+
+#include "complain.h"
+#include "conflicts.h"
#include "files.h"
-#include "symtab.h"
-#include "options.h"
+#include "getargs.h"
#include "gram.h"
-#include "complain.h"
-#include "output.h"
+#include "muscle-tab.h"
#include "reader.h"
-#include "conflicts.h"
-#include "muscle_tab.h"
+#include "symlist.h"
+#include "symtab.h"
+#include "scan-gram.h"
+#include "scan-code.h"
+
+static void prepare_percent_define_front_end_variables (void);
+static void check_and_convert_grammar (void);
-int lineno;
static symbol_list *grammar = NULL;
-static int start_flag = 0;
+static bool start_flag = false;
+merger_list *merge_functions;
-/* Nonzero if %union has been seen. */
-int typed = 0;
+/* Was %union seen? */
+bool union_seen = false;
-static symbol_list *
-symbol_list_new (symbol_t *sym)
-{
- symbol_list *res = XMALLOC (symbol_list, 1);
- res->next = NULL;
- res->sym = sym;
- res->line = lineno;
- res->action = NULL;
- res->action_line = 0;
- res->ruleprec = NULL;
- return res;
-}
+/* Was a tag seen? */
+bool tag_seen = false;
+/* Should rules have a default precedence? */
+bool default_prec = true;
-/*--------------------------------------------------------------.
-| Get the data type (alternative in the union) of the value for |
-| symbol N in rule RULE. |
-`--------------------------------------------------------------*/
-
-char *
-get_type_name (int n, symbol_list *rule)
-{
- int i;
- symbol_list *rp;
-
- if (n < 0)
- {
- complain (_("invalid $ value"));
- return NULL;
- }
-
- rp = rule;
- i = 0;
-
- while (i < n)
- {
- rp = rp->next;
- if (rp == NULL || rp->sym == NULL)
- {
- complain (_("invalid $ value"));
- return NULL;
- }
- ++i;
- }
-
- return rp->sym->type_name;
-}
-
-
/*-----------------------.
| Set the start symbol. |
`-----------------------*/
void
-grammar_start_symbol_set (symbol_t *s)
+grammar_start_symbol_set (symbol *sym, location loc)
{
if (start_flag)
- complain (_("multiple %s declarations"), "%start");
+ complain_at (loc, _("multiple %s declarations"), "%start");
else
{
- start_flag = 1;
- startsymbol = s;
+ start_flag = true;
+ startsymbol = sym;
+ startsymbol_location = loc;
}
}
+
-/*----------------------------------------------------------------.
-| There are two prologues: one before %union, one after. Augment |
-| the current one. |
-`----------------------------------------------------------------*/
+/*------------------------------------------------------------------------.
+| Return the merger index for a merging function named NAME. Records the |
+| function, if new, in MERGER_LIST. |
+`------------------------------------------------------------------------*/
-void
-prologue_augment (const char *prologue, int location)
+static int
+get_merge_function (uniqstr name)
{
- struct obstack *oout =
- !typed ? &pre_prologue_obstack : &post_prologue_obstack;
-
- if (!no_lines_flag)
+ merger_list *syms;
+ merger_list head;
+ int n;
+
+ if (! glr_parser)
+ return 0;
+
+ head.next = merge_functions;
+ for (syms = &head, n = 1; syms->next; syms = syms->next, n += 1)
+ if (UNIQSTR_EQ (name, syms->next->name))
+ break;
+ if (syms->next == NULL)
{
- obstack_fgrow2 (oout, muscle_find ("linef"),
- location, quotearg_style (c_quoting_style,
- muscle_find ("filename")));
+ syms->next = xmalloc (sizeof syms->next[0]);
+ syms->next->name = uniqstr_new (name);
+ /* After all symbol type declarations have been parsed, packgram invokes
+ record_merge_function_type to set the type. */
+ syms->next->type = NULL;
+ syms->next->next = NULL;
+ merge_functions = head.next;
}
- obstack_sgrow (oout, prologue);
+ return n;
}
+/*-------------------------------------------------------------------------.
+| For the existing merging function with index MERGER, record the result |
+| type as TYPE as required by the lhs of the rule whose %merge declaration |
+| is at DECLARATION_LOC. |
+`-------------------------------------------------------------------------*/
+static void
+record_merge_function_type (int merger, uniqstr type, location declaration_loc)
+{
+ int merger_find;
+ merger_list *merge_function;
+ if (merger <= 0)
+ return;
-/*----------------------.
-| Handle the epilogue. |
-`----------------------*/
+ if (type == NULL)
+ type = uniqstr_new ("");
-void
-epilogue_set (const char *epilogue, int location)
-{
- struct obstack el_obstack;
- obstack_init (&el_obstack);
-
- if (!no_lines_flag)
+ merger_find = 1;
+ for (merge_function = merge_functions;
+ merge_function != NULL && merger_find != merger;
+ merge_function = merge_function->next)
+ merger_find += 1;
+ aver (merge_function != NULL && merger_find == merger);
+ if (merge_function->type != NULL && !UNIQSTR_EQ (merge_function->type, type))
{
- obstack_fgrow2 (&el_obstack, muscle_find ("linef"),
- location, quotearg_style (c_quoting_style,
- muscle_find ("filename")));
+ complain_at (declaration_loc,
+ _("result type clash on merge function %s: <%s> != <%s>"),
+ quote (merge_function->name), type, merge_function->type);
+ complain_at (merge_function->type_declaration_location,
+ _("previous declaration"));
}
- obstack_sgrow (&el_obstack, epilogue);
- obstack_1grow (&el_obstack, 0);
- muscle_insert ("epilogue", obstack_finish (&el_obstack));
+ merge_function->type = uniqstr_new (type);
+ merge_function->type_declaration_location = declaration_loc;
}
+/*--------------------------------------.
+| Free all merge-function definitions. |
+`--------------------------------------*/
-
-
-/*-------------------------------------------------------------------.
-| Generate a dummy symbol, a nonterminal, whose name cannot conflict |
-| with the user's names. |
-`-------------------------------------------------------------------*/
-
-static symbol_t *
-gensym (void)
+void
+free_merger_functions (void)
{
- /* Incremented for each generated symbol */
- static int gensym_count = 0;
- static char buf[256];
-
- symbol_t *sym;
-
- sprintf (buf, "@%d", ++gensym_count);
- sym = getsym (buf);
- sym->class = nterm_sym;
- sym->number = nvars++;
- return sym;
+ merger_list *L0 = merge_functions;
+ while (L0)
+ {
+ merger_list *L1 = L0->next;
+ free (L0);
+ L0 = L1;
+ }
}
+
/*-------------------------------------------------------------------.
| Parse the input grammar into a one symbol_list structure. Each |
@@ -184,23 +164,16 @@ gensym (void)
| |
| All actions are copied out, labelled by the rule number they apply |
| to. |
-| |
-| Bison used to allow some %directives in the rules sections, but |
-| this is no longer consider appropriate: (i) the documented grammar |
-| doesn't claim it, (ii), it would promote bad style, (iii), error |
-| recovery for %directives consists in skipping the junk until a `%' |
-| is seen and helrp synchronizing. This scheme is definitely wrong |
-| in the rules section. |
`-------------------------------------------------------------------*/
/* The (currently) last symbol of GRAMMAR. */
-symbol_list *grammar_end = NULL;
+static symbol_list *grammar_end = NULL;
-/* Append S to the GRAMMAR. */
-void
-grammar_symbol_append (symbol_t *s)
+/* Append SYM to the grammar. */
+static symbol_list *
+grammar_symbol_append (symbol *sym, location loc)
{
- symbol_list *p = symbol_list_new (s);
+ symbol_list *p = symbol_list_sym_new (sym, loc);
if (grammar_end)
grammar_end->next = p;
@@ -208,35 +181,60 @@ grammar_symbol_append (symbol_t *s)
grammar = p;
grammar_end = p;
+
+ /* A null SYM stands for an end of rule; it is not an actual
+ part of it. */
+ if (sym)
+ ++nritems;
+
+ return p;
}
-/* The rule currently being defined, and the previous rule. Point to
- the first symbol of each list: their lhs. */
-symbol_list *current_rule = NULL;
-symbol_list *previous_rule = NULL;
+static void
+assign_named_ref (symbol_list *p, named_ref *name)
+{
+ symbol *sym = p->content.sym;
+ if (name->id == sym->tag)
+ {
+ warn_at (name->loc,
+ _("duplicated symbol name for %s ignored"),
+ quote (sym->tag));
+ named_ref_free (name);
+ }
+ else
+ p->named_ref = name;
+}
+
+
+/* The rule currently being defined, and the previous rule.
+ CURRENT_RULE points to the first LHS of the current rule, while
+ PREVIOUS_RULE_END points to the *end* of the previous rule (NULL). */
+static symbol_list *current_rule = NULL;
+static symbol_list *previous_rule_end = NULL;
-/* Create a new rule for LHS in to the GRAMMAR. */
+
+/*----------------------------------------------.
+| Create a new rule for LHS in to the GRAMMAR. |
+`----------------------------------------------*/
void
-grammar_rule_begin (symbol_t *lhs)
+grammar_current_rule_begin (symbol *lhs, location loc,
+ named_ref *lhs_name)
{
- if (!start_flag)
- {
- startsymbol = lhs;
- start_flag = 1;
- }
+ symbol_list* p;
/* Start a new rule and record its lhs. */
++nrules;
- ++nritems;
+ previous_rule_end = grammar_end;
+
+ p = grammar_symbol_append (lhs, loc);
+ if (lhs_name)
+ assign_named_ref (p, named_ref_copy (lhs_name));
- previous_rule = grammar_end;
- grammar_symbol_append (lhs);
current_rule = grammar_end;
/* Mark the rule's lhs as a nonterminal if not already so. */
-
if (lhs->class == unknown_sym)
{
lhs->class = nterm_sym;
@@ -244,57 +242,122 @@ grammar_rule_begin (symbol_t *lhs)
++nvars;
}
else if (lhs->class == token_sym)
- complain (_("rule given for %s, which is a token"), lhs->tag);
+ complain_at (loc, _("rule given for %s, which is a token"), lhs->tag);
}
-/* Check that the last rule (CURRENT_RULE) is properly defined. For
- instance, there should be no type clash on the default action. */
+
+/*----------------------------------------------------------------------.
+| A symbol should be used if either: |
+| 1. It has a destructor. |
+| 2. The symbol is a mid-rule symbol (i.e., the generated LHS |
+| replacing a mid-rule action) that was assigned to or used, as in |
+| "exp: { $$ = 1; } { $$ = $1; }". |
+`----------------------------------------------------------------------*/
+
+static bool
+symbol_should_be_used (symbol_list const *s, bool *midrule_warning)
+{
+ if (symbol_destructor_get (s->content.sym)->code)
+ return true;
+ if ((s->midrule && s->midrule->action_props.is_value_used)
+ || (s->midrule_parent_rule
+ && symbol_list_n_get (s->midrule_parent_rule,
+ s->midrule_parent_rhs_index)
+ ->action_props.is_value_used))
+ {
+ *midrule_warning = true;
+ return true;
+ }
+ return false;
+}
+
+/*----------------------------------------------------------------.
+| Check that the rule R is properly defined. For instance, there |
+| should be no type clash on the default action. |
+`----------------------------------------------------------------*/
static void
-grammar_current_rule_check (void)
+grammar_rule_check (const symbol_list *r)
{
- symbol_t *lhs = current_rule->sym;
- symbol_t *first_rhs = current_rule->next->sym;
+ /* Type check.
- /* If there is an action, then there is nothing we can do: the user
- is allowed to shoot in her foot. */
- if (current_rule->action)
- return;
+ If there is an action, then there is nothing we can do: the user
+ is allowed to shoot herself in the foot.
- /* If $$ is being set in default way, report if any type mismatch.
- */
- if (first_rhs)
+ Don't worry about the default action if $$ is untyped, since $$'s
+ value can't be used. */
+ if (!r->action_props.code && r->content.sym->type_name)
{
- const char *lhs_type = lhs->type_name ? lhs->type_name : "";
- const char *rhs_type = first_rhs->type_name ? first_rhs->type_name : "";
- if (strcmp (lhs_type, rhs_type))
- complain (_("type clash (`%s' `%s') on default action"),
- lhs_type, rhs_type);
- }
- /* Warn if there is no default for $$ but we need one. */
- else
- {
- if (lhs->type_name)
- complain (_("empty rule for typed nonterminal, and no action"));
+ symbol *first_rhs = r->next->content.sym;
+ /* If $$ is being set in default way, report if any type mismatch. */
+ if (first_rhs)
+ {
+ char const *lhs_type = r->content.sym->type_name;
+ const char *rhs_type =
+ first_rhs->type_name ? first_rhs->type_name : "";
+ if (!UNIQSTR_EQ (lhs_type, rhs_type))
+ warn_at (r->location,
+ _("type clash on default action: <%s> != <%s>"),
+ lhs_type, rhs_type);
+ }
+ /* Warn if there is no default for $$ but we need one. */
+ else
+ warn_at (r->location,
+ _("empty rule for typed nonterminal, and no action"));
}
+
+ /* Check that symbol values that should be used are in fact used. */
+ {
+ symbol_list const *l = r;
+ int n = 0;
+ for (; l && l->content.sym; l = l->next, ++n)
+ {
+ bool midrule_warning = false;
+ if (!l->action_props.is_value_used
+ && symbol_should_be_used (l, &midrule_warning)
+ /* The default action, $$ = $1, `uses' both. */
+ && (r->action_props.code || (n != 0 && n != 1)))
+ {
+ void (*warn_at_ptr)(location, char const*, ...) =
+ midrule_warning ? midrule_value_at : warn_at;
+ if (n)
+ warn_at_ptr (r->location, _("unused value: $%d"), n);
+ else
+ warn_at_ptr (r->location, _("unset value: $$"));
+ }
+ }
+ }
+
+ /* See comments in grammar_current_rule_prec_set for how POSIX
+ mandates this complaint. It's only for identifiers, so skip
+ it for char literals and strings, which are always tokens. */
+ if (r->ruleprec
+ && r->ruleprec->tag[0] != '\'' && r->ruleprec->tag[0] != '"'
+ && !r->ruleprec->declared && !r->ruleprec->prec)
+ warn_at (r->location, _("token for %%prec is not defined: %s"),
+ r->ruleprec->tag);
}
-/* End the currently being grown rule. */
+/*-------------------------------------.
+| End the currently being grown rule. |
+`-------------------------------------*/
void
-grammar_rule_end (void)
+grammar_current_rule_end (location loc)
{
/* Put an empty link in the list to mark the end of this rule */
- grammar_symbol_append (NULL);
- grammar_current_rule_check ();
+ grammar_symbol_append (NULL, grammar_end->location);
+ current_rule->location = loc;
}
-/* The previous action turns out the be a mid-rule action. Attach it
- to the current rule, i.e., create a dummy symbol, attach it this
- mid-rule action, and append this dummy nonterminal to the current
- rule. */
+/*-------------------------------------------------------------------.
+| The previous action turns out the be a mid-rule action. Attach it |
+| to the current rule, i.e., create a dummy symbol, attach it this |
+| mid-rule action, and append this dummy nonterminal to the current |
+| rule. |
+`-------------------------------------------------------------------*/
void
grammar_midrule_action (void)
@@ -303,70 +366,124 @@ grammar_midrule_action (void)
give the new rule this number by inserting the new rule before
it. */
- /* Make a dummy nonterminal, a gensym. */
- symbol_t *sdummy = gensym ();
- symbol_list *midrule_action = symbol_list_new (sdummy);
+ /* Make a DUMMY nonterminal, whose location is that of the midrule
+ action. Create the MIDRULE. */
+ location dummy_location = current_rule->action_props.location;
+ symbol *dummy = dummy_symbol_get (dummy_location);
+ symbol_list *midrule = symbol_list_sym_new (dummy, dummy_location);
+
+ /* Remember named_ref of previous action. */
+ named_ref *action_name = current_rule->action_props.named_ref;
/* Make a new rule, whose body is empty, before the current one, so
that the action just read can belong to it. */
++nrules;
++nritems;
- /* Attach its lineno to that of the host rule. */
- midrule_action->line = current_rule->line;
- /* Move the action from the host rule to this one. */
- midrule_action->action = current_rule->action;
- midrule_action->action_line = current_rule->action_line;
- current_rule->action = NULL;
-
- if (previous_rule)
- previous_rule->next = midrule_action;
+ /* Attach its location and actions to that of the DUMMY. */
+ midrule->location = dummy_location;
+ code_props_rule_action_init (&midrule->action_props,
+ current_rule->action_props.code,
+ current_rule->action_props.location,
+ midrule, 0,
+ current_rule->action_props.is_predicate);
+ code_props_none_init (¤t_rule->action_props);
+
+ if (previous_rule_end)
+ previous_rule_end->next = midrule;
else
- grammar = midrule_action;
+ grammar = midrule;
- /* End of the rule. */
- previous_rule = symbol_list_new (NULL);
- previous_rule->next = current_rule;
+ /* End the dummy's rule. */
+ midrule->next = symbol_list_sym_new (NULL, dummy_location);
+ midrule->next->next = current_rule;
- midrule_action->next = previous_rule;
+ previous_rule_end = midrule->next;
- /* Insert the dummy generated by that rule into this rule. */
- ++nritems;
- grammar_symbol_append (sdummy);
+ /* Insert the dummy nonterminal replacing the midrule action into
+ the current rule. Bind it to its dedicated rule. */
+ grammar_current_rule_symbol_append (dummy, dummy_location,
+ action_name);
+ grammar_end->midrule = midrule;
+ midrule->midrule_parent_rule = current_rule;
+ midrule->midrule_parent_rhs_index = symbol_list_length (current_rule->next);
}
/* Set the precedence symbol of the current rule to PRECSYM. */
void
-grammar_current_rule_prec_set (symbol_t *precsym)
+grammar_current_rule_prec_set (symbol *precsym, location loc)
{
+ /* POSIX says that any identifier is a nonterminal if it does not
+ appear on the LHS of a grammar rule and is not defined by %token
+ or by one of the directives that assigns precedence to a token. We
+ ignore this here because the only kind of identifier that POSIX
+ allows to follow a %prec is a token and because assuming it's a
+ token now can produce more logical error messages. Nevertheless,
+ grammar_rule_check does obey what we believe is the real intent of
+ POSIX here: that an error be reported for any identifier that
+ appears after %prec but that is not defined separately as a
+ token. */
+ symbol_class_set (precsym, token_sym, loc, false);
if (current_rule->ruleprec)
- complain (_("two @prec's in a row"));
+ complain_at (loc, _("only one %s allowed per rule"), "%prec");
current_rule->ruleprec = precsym;
}
-/* Attach a SYMBOL to the current rule. If needed, move the previous
- action as a mid-rule action. */
+/* Attach dynamic precedence DPREC to the current rule. */
void
-grammar_current_rule_symbol_append (symbol_t *symbol)
+grammar_current_rule_dprec_set (int dprec, location loc)
{
- if (current_rule->action)
- grammar_midrule_action ();
- ++nritems;
- grammar_symbol_append (symbol);
+ if (! glr_parser)
+ warn_at (loc, _("%s affects only GLR parsers"), "%dprec");
+ if (dprec <= 0)
+ complain_at (loc, _("%s must be followed by positive number"), "%dprec");
+ else if (current_rule->dprec != 0)
+ complain_at (loc, _("only one %s allowed per rule"), "%dprec");
+ current_rule->dprec = dprec;
}
+/* Attach a merge function NAME with argument type TYPE to current
+ rule. */
+
+void
+grammar_current_rule_merge_set (uniqstr name, location loc)
+{
+ if (! glr_parser)
+ warn_at (loc, _("%s affects only GLR parsers"), "%merge");
+ if (current_rule->merger != 0)
+ complain_at (loc, _("only one %s allowed per rule"), "%merge");
+ current_rule->merger = get_merge_function (name);
+ current_rule->merger_declaration_location = loc;
+}
-/* Attach an ACTION to the current rule. If needed, move the previous
+/* Attach SYM to the current rule. If needed, move the previous
action as a mid-rule action. */
void
-grammar_current_rule_action_append (const char *action, int action_line)
+grammar_current_rule_symbol_append (symbol *sym, location loc,
+ named_ref *name)
+{
+ symbol_list *p;
+ if (current_rule->action_props.code)
+ grammar_midrule_action ();
+ p = grammar_symbol_append (sym, loc);
+ if (name)
+ assign_named_ref(p, name);
+}
+
+/* Attach an ACTION to the current rule. */
+
+void
+grammar_current_rule_action_append (const char *action, location loc,
+ named_ref *name, bool is_predicate)
{
- if (current_rule->action)
+ if (current_rule->action_props.code)
grammar_midrule_action ();
- current_rule->action = action;
- current_rule->action_line = action_line;
+ /* After all symbol declarations have been parsed, packgram invokes
+ code_props_translate_code. */
+ code_props_rule_action_init (¤t_rule->action_props, action, loc,
+ current_rule, name, is_predicate);
}
@@ -378,60 +495,92 @@ grammar_current_rule_action_append (const char *action, int action_line)
static void
packgram (void)
{
- unsigned int itemno;
- int ruleno;
- symbol_list *p;
+ unsigned int itemno = 0;
+ rule_number ruleno = 0;
+ symbol_list *p = grammar;
- ritem = XCALLOC (item_number_t, nritems);
- rules = XCALLOC (rule_t, nrules) - 1;
+ ritem = xnmalloc (nritems + 1, sizeof *ritem);
- itemno = 0;
- ruleno = 1;
+ /* This sentinel is used by build_relations in gram.c. */
+ *ritem++ = 0;
+
+ rules = xnmalloc (nrules, sizeof *rules);
- p = grammar;
while (p)
{
- symbol_t *ruleprec = p->ruleprec;
+ int rule_length = 0;
+ symbol *ruleprec = p->ruleprec;
+ record_merge_function_type (p->merger, p->content.sym->type_name,
+ p->merger_declaration_location);
rules[ruleno].user_number = ruleno;
rules[ruleno].number = ruleno;
- rules[ruleno].lhs = p->sym;
+ rules[ruleno].lhs = p->content.sym;
rules[ruleno].rhs = ritem + itemno;
- rules[ruleno].line = p->line;
- rules[ruleno].useful = TRUE;
- rules[ruleno].action = p->action;
- rules[ruleno].action_line = p->action_line;
-
- p = p->next;
- while (p && p->sym)
- {
- /* item_number_t = symbol_number_t.
- But the former needs to contain more: negative rule numbers. */
- ritem[itemno++] = symbol_number_as_item_number (p->sym->number);
- /* A rule gets by default the precedence and associativity
- of the last token in it. */
- if (p->sym->class == token_sym)
- rules[ruleno].prec = p->sym;
- if (p)
- p = p->next;
- }
+ rules[ruleno].prec = NULL;
+ rules[ruleno].dprec = p->dprec;
+ rules[ruleno].merger = p->merger;
+ rules[ruleno].precsym = NULL;
+ rules[ruleno].location = p->location;
+ rules[ruleno].useful = true;
+ rules[ruleno].action = p->action_props.code;
+ rules[ruleno].action_location = p->action_props.location;
+ rules[ruleno].is_predicate = p->action_props.is_predicate;
+
+ /* If the midrule's $$ is set or its $n is used, remove the `$' from the
+ symbol name so that it's a user-defined symbol so that the default
+ %destructor and %printer apply. */
+ if (p->midrule_parent_rule
+ && (p->action_props.is_value_used
+ || symbol_list_n_get (p->midrule_parent_rule,
+ p->midrule_parent_rhs_index)
+ ->action_props.is_value_used))
+ p->content.sym->tag += 1;
+
+ /* Don't check the generated rule 0. It has no action, so some rhs
+ symbols may appear unused, but the parsing algorithm ensures that
+ %destructor's are invoked appropriately. */
+ if (p != grammar)
+ grammar_rule_check (p);
+
+ for (p = p->next; p && p->content.sym; p = p->next)
+ {
+ ++rule_length;
+
+ /* Don't allow rule_length == INT_MAX, since that might
+ cause confusion with strtol if INT_MAX == LONG_MAX. */
+ if (rule_length == INT_MAX)
+ fatal_at (rules[ruleno].location, _("rule is too long"));
+
+ /* item_number = symbol_number.
+ But the former needs to contain more: negative rule numbers. */
+ ritem[itemno++] =
+ symbol_number_as_item_number (p->content.sym->number);
+ /* A rule gets by default the precedence and associativity
+ of its last token. */
+ if (p->content.sym->class == token_sym && default_prec)
+ rules[ruleno].prec = p->content.sym;
+ }
/* If this rule has a %prec,
the specified symbol's precedence replaces the default. */
if (ruleprec)
- {
- rules[ruleno].precsym = ruleprec;
- rules[ruleno].prec = ruleprec;
- }
- ritem[itemno++] = -ruleno;
+ {
+ rules[ruleno].precsym = ruleprec;
+ rules[ruleno].prec = ruleprec;
+ }
+ /* An item ends by the rule number (negated). */
+ ritem[itemno++] = rule_number_as_item_number (ruleno);
+ aver (itemno < ITEM_NUMBER_MAX);
++ruleno;
+ aver (ruleno < RULE_NUMBER_MAX);
if (p)
- p = p->next;
+ p = p->next;
}
- assert (itemno == nritems);
+ aver (itemno == nritems);
- if (trace_flag)
+ if (trace_flag & trace_sets)
ritem_print (stderr);
}
@@ -445,92 +594,154 @@ packgram (void)
void
reader (void)
{
- gram_control_t gram_control;
- lineno = 1;
-
- /* Initialize the muscle obstack. */
- obstack_init (&muscle_obstack);
-
/* Initialize the symbol table. */
symbols_new ();
- /* Construct the axiom symbol. */
- axiom = getsym ("$axiom");
- axiom->class = nterm_sym;
- axiom->number = nvars++;
+ /* Construct the accept symbol. */
+ accept = symbol_get ("$accept", empty_location);
+ accept->class = nterm_sym;
+ accept->number = nvars++;
/* Construct the error token */
- errtoken = getsym ("error");
+ errtoken = symbol_get ("error", empty_location);
errtoken->class = token_sym;
errtoken->number = ntokens++;
/* Construct a token that represents all undefined literal tokens.
It is always token number 2. */
- undeftoken = getsym ("$undefined.");
+ undeftoken = symbol_get ("$undefined", empty_location);
undeftoken->class = token_sym;
undeftoken->number = ntokens++;
- /* Initialize the obstacks. */
- obstack_init (&action_obstack);
- obstack_init (&output_obstack);
- obstack_init (&pre_prologue_obstack);
- obstack_init (&post_prologue_obstack);
+ gram_in = xfopen (grammar_file, "r");
+
+ gram__flex_debug = trace_flag & trace_scan;
+ gram_debug = trace_flag & trace_parse;
+ gram_scanner_initialize ();
+ gram_parse ();
+ prepare_percent_define_front_end_variables ();
+
+ if (! complaint_issued)
+ check_and_convert_grammar ();
+
+ xfclose (gram_in);
+}
+
+static void
+prepare_percent_define_front_end_variables (void)
+{
+ /* Set %define front-end variable defaults. */
+ muscle_percent_define_default ("lr.keep-unreachable-states", "false");
+ {
+ char *lr_type;
+ /* IELR would be a better default, but LALR is historically the
+ default. */
+ muscle_percent_define_default ("lr.type", "lalr");
+ lr_type = muscle_percent_define_get ("lr.type");
+ if (STRNEQ (lr_type, "canonical-lr"))
+ muscle_percent_define_default ("lr.default-reductions", "most");
+ else
+ muscle_percent_define_default ("lr.default-reductions", "accepting");
+ free (lr_type);
+ }
+
+ /* Check %define front-end variables. */
+ {
+ static char const * const values[] = {
+ "lr.type", "lalr", "ielr", "canonical-lr", NULL,
+ "lr.default-reductions", "most", "consistent", "accepting", NULL,
+ NULL
+ };
+ muscle_percent_define_check_values (values);
+ }
+}
- finput = xfopen (infile, "r");
- gram_in = finput;
- gram_debug = !!getenv ("parse");
- gram__flex_debug = !!getenv ("scan");
- gram_parse (&gram_control);
+/*-------------------------------------------------------------.
+| Check the grammar that has just been read, and convert it to |
+| internal form. |
+`-------------------------------------------------------------*/
- /* Grammar has been read. Do some checking */
+static void
+check_and_convert_grammar (void)
+{
+ /* Grammar has been read. Do some checking. */
if (nrules == 0)
fatal (_("no rules in the input grammar"));
+ /* If the user did not define her ENDTOKEN, do it now. */
+ if (!endtoken)
+ {
+ endtoken = symbol_get ("$end", empty_location);
+ endtoken->class = token_sym;
+ endtoken->number = 0;
+ /* Value specified by POSIX. */
+ endtoken->user_token_number = 0;
+ }
+
/* Report any undefined symbols and consider them nonterminals. */
symbols_check_defined ();
- /* If the user did not define her EOFTOKEN, do it now. */
- if (!eoftoken)
+ /* Find the start symbol if no %start. */
+ if (!start_flag)
{
- eoftoken = getsym ("$");
- eoftoken->class = token_sym;
- eoftoken->number = 0;
- /* Value specified by POSIX. */
- eoftoken->user_token_number = 0;
+ symbol_list *node;
+ for (node = grammar;
+ node != NULL && symbol_is_dummy (node->content.sym);
+ node = node->next)
+ {
+ for (node = node->next;
+ node != NULL && node->content.sym != NULL;
+ node = node->next)
+ ;
+ }
+ aver (node != NULL);
+ grammar_start_symbol_set (node->content.sym,
+ node->content.sym->location);
}
- /* Insert the initial rule, which line is that of the first rule
+ /* Insert the initial rule, whose line is that of the first rule
(not that of the start symbol):
- axiom: %start EOF. */
+ accept: %start EOF. */
{
- symbol_list *p = symbol_list_new (axiom);
- p->line = grammar->line;
- p->next = symbol_list_new (startsymbol);
- p->next->next = symbol_list_new (eoftoken);
- p->next->next->next = symbol_list_new (NULL);
+ symbol_list *p = symbol_list_sym_new (accept, empty_location);
+ p->location = grammar->location;
+ p->next = symbol_list_sym_new (startsymbol, empty_location);
+ p->next->next = symbol_list_sym_new (endtoken, empty_location);
+ p->next->next->next = symbol_list_sym_new (NULL, empty_location);
p->next->next->next->next = grammar;
nrules += 1;
nritems += 3;
grammar = p;
}
- if (nsyms > SHRT_MAX)
- fatal (_("too many symbols (tokens plus nonterminals); maximum %d"),
- SHRT_MAX);
-
- assert (nsyms == ntokens + nvars);
-
- xfclose (finput);
+ aver (nsyms <= SYMBOL_NUMBER_MAXIMUM && nsyms == ntokens + nvars);
/* Assign the symbols their symbol numbers. Write #defines for the
token symbols into FDEFINES if requested. */
symbols_pack ();
+ /* Scan rule actions after invoking symbol_check_alias_consistency (in
+ symbols_pack above) so that token types are set correctly before the rule
+ action type checking.
+
+ Before invoking grammar_rule_check (in packgram below) on any rule, make
+ sure all actions have already been scanned in order to set `used' flags.
+ Otherwise, checking that a midrule's $$ should be set will not always work
+ properly because the check must forward-reference the midrule's parent
+ rule. For the same reason, all the `used' flags must be set before
+ checking whether to remove `$' from any midrule symbol name (also in
+ packgram). */
+ {
+ symbol_list *sym;
+ for (sym = grammar; sym; sym = sym->next)
+ code_props_translate_code (&sym->action_props);
+ }
+
/* Convert the grammar into the format described in gram.h. */
packgram ();
/* The grammar as a symbol_list is no longer needed. */
- LIST_FREE (symbol_list, grammar);
+ symbol_list_free (grammar);
}