X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/d945f5cd8e85c0343da52dc720d23624e1c28661..0db2648930e3b6c376a539aabe368aade83ee29a:/src/reader.c?ds=sidebyside
diff --git a/src/reader.c b/src/reader.c
index d7d6e86d..86fde7b2 100644
--- a/src/reader.c
+++ b/src/reader.c
@@ -1,1898 +1,749 @@
-/* Input parser for bison
- Copyright 1984, 1986, 1989, 1992, 1998, 2000, 2001
- 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 "lex.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"
-
-typedef struct symbol_list
-{
- struct symbol_list *next;
- bucket *sym;
- int line;
- /* The action is attached to the LHS of a rule. */
- const char *action;
- int action_line;
- bucket *ruleprec;
-} symbol_list;
-
-int lineno;
-char **tags;
-short *user_toknums;
-static symbol_list *grammar;
-static int start_flag;
-static bucket *startval;
-
-/* Nonzero if components of semantic values are used, implying
- they must be unions. */
-static int value_components_used;
+#include "symlist.h"
+#include "symtab.h"
+#include "scan-gram.h"
+#include "scan-code.h"
-/* Nonzero if %union has been seen. */
-static int typed;
+static void prepare_percent_define_front_end_variables (void);
+static void check_and_convert_grammar (void);
-/* Incremented for each %left, %right or %nonassoc seen */
-static int lastprec;
+static symbol_list *grammar = NULL;
+static bool start_flag = false;
+merger_list *merge_functions;
-static bucket *errtoken;
-static bucket *undeftoken;
+/* Was %union seen? */
+bool union_seen = false;
+/* Was a tag seen? */
+bool tag_seen = false;
-static symbol_list *
-symbol_list_new (bucket *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;
-}
-
+/* Should rules have a default precedence? */
+bool default_prec = true;
+/*-----------------------.
+| Set the start symbol. |
+`-----------------------*/
-/*===================\
-| Low level lexing. |
-\===================*/
-
-static void
-skip_to_char (int target)
+void
+grammar_start_symbol_set (symbol *sym, location loc)
{
- int c;
- if (target == '\n')
- complain (_(" Skipping to next \\n"));
+ if (start_flag)
+ complain_at (loc, _("multiple %s declarations"), "%start");
else
- complain (_(" Skipping to next %c"), target);
-
- do
- c = skip_white_space ();
- while (c != target && c != EOF);
- if (c != EOF)
- ungetc (c, finput);
-}
-
-
-/*---------------------------------------------------------.
-| Read a signed integer from STREAM and return its value. |
-`---------------------------------------------------------*/
-
-static inline int
-read_signed_integer (FILE *stream)
-{
- int c = getc (stream);
- int sign = 1;
- int n = 0;
-
- if (c == '-')
{
- c = getc (stream);
- sign = -1;
+ start_flag = true;
+ startsymbol = sym;
+ startsymbol_location = loc;
}
-
- while (isdigit (c))
- {
- n = 10 * n + (c - '0');
- c = getc (stream);
- }
-
- ungetc (c, stream);
-
- return sign * n;
}
-
-/*--------------------------------------------------------------.
-| Get the data type (alternative in the union) of the value for |
-| symbol N in rule RULE. |
-`--------------------------------------------------------------*/
-
-static 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;
-}
-/*------------------------------------------------------------.
-| Dump the string from FIN to OOUT if non null. MATCH is the |
-| delimiter of the string (either ' or "). |
-`------------------------------------------------------------*/
-
-static inline void
-copy_string2 (FILE *fin, struct obstack *oout, int match, int store)
-{
- int c;
-
- if (store)
- obstack_1grow (oout, match);
-
- c = getc (fin);
-
- while (c != match)
- {
- if (c == EOF)
- fatal (_("unterminated string at end of file"));
- if (c == '\n')
- {
- complain (_("unterminated string"));
- ungetc (c, fin);
- c = match; /* invent terminator */
- continue;
- }
- obstack_1grow (oout, c);
+/*------------------------------------------------------------------------.
+| Return the merger index for a merging function named NAME. Records the |
+| function, if new, in MERGER_LIST. |
+`------------------------------------------------------------------------*/
- if (c == '\\')
- {
- c = getc (fin);
- if (c == EOF)
- fatal (_("unterminated string at end of file"));
- obstack_1grow (oout, c);
-
- if (c == '\n')
- lineno++;
- }
-
- c = getc (fin);
- }
-
- if (store)
- obstack_1grow (oout, c);
-}
-
-/* FIXME. */
-
-static inline void
-copy_string (FILE *fin, struct obstack *oout, int match)
-{
- copy_string2 (fin, oout, match, 1);
-}
-
-/* FIXME. */
-
-static inline void
-copy_identifier (FILE *fin, struct obstack *oout)
-{
- int c;
-
- while (isalnum (c = getc (fin)) || c == '_')
- obstack_1grow (oout, c);
-
- ungetc (c, fin);
-}
-
-
-/*------------------------------------------------------------------.
-| Dump the wannabee comment from IN to OOUT. In fact we just saw a |
-| `/', which might or might not be a comment. In any case, copy |
-| what we saw. |
-`------------------------------------------------------------------*/
-
-static inline void
-copy_comment (FILE *fin, struct obstack *oout)
+static int
+get_merge_function (uniqstr name)
{
- int cplus_comment;
- int ended;
- int c;
+ merger_list *syms;
+ merger_list head;
+ int n;
- /* We read a `/', output it. */
- obstack_1grow (oout, '/');
+ if (! glr_parser)
+ return 0;
- switch ((c = getc (fin)))
- {
- case '/':
- cplus_comment = 1;
+ head.next = merge_functions;
+ for (syms = &head, n = 1; syms->next; syms = syms->next, n += 1)
+ if (UNIQSTR_EQ (name, syms->next->name))
break;
- case '*':
- cplus_comment = 0;
- break;
- default:
- ungetc (c, fin);
- return;
- }
-
- obstack_1grow (oout, c);
- c = getc (fin);
-
- ended = 0;
- while (!ended)
+ if (syms->next == NULL)
{
- if (!cplus_comment && c == '*')
- {
- while (c == '*')
- {
- obstack_1grow (oout, c);
- c = getc (fin);
- }
-
- if (c == '/')
- {
- obstack_1grow (oout, c);
- ended = 1;
- }
- }
- else if (c == '\n')
- {
- lineno++;
- obstack_1grow (oout, c);
- if (cplus_comment)
- ended = 1;
- else
- c = getc (fin);
- }
- else if (c == EOF)
- fatal (_("unterminated comment"));
- else
- {
- obstack_1grow (oout, c);
- c = getc (fin);
- }
+ 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;
}
+ 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. |
+`-------------------------------------------------------------------------*/
-/*-----------------------------------------------------------------.
-| FIN is pointing to a location (i.e., a `@'). Output to OOUT a |
-| reference to this location. STACK_OFFSET is the number of values |
-| in the current rule so far, which says where to find `$0' with |
-| respect to the top of the stack. |
-`-----------------------------------------------------------------*/
+static void
+record_merge_function_type (int merger, uniqstr type, location declaration_loc)
+{
+ int merger_find;
+ merger_list *merge_function;
+
+ if (merger <= 0)
+ return;
+
+ if (type == NULL)
+ type = uniqstr_new ("");
+
+ merger_find = 1;
+ for (merge_function = merge_functions;
+ merge_function != NULL && merger_find != merger;
+ merge_function = merge_function->next)
+ merger_find += 1;
+ aver (merge_function != NULL && merger_find == merger);
+ if (merge_function->type != NULL && !UNIQSTR_EQ (merge_function->type, type))
+ {
+ unsigned indent = 0;
+ complain_at_indent (declaration_loc, &indent,
+ _("result type clash on merge function %s: "
+ "<%s> != <%s>"),
+ quote (merge_function->name), type,
+ merge_function->type);
+ indent += SUB_INDENT;
+ complain_at_indent (merge_function->type_declaration_location, &indent,
+ _("previous declaration"));
+ }
+ merge_function->type = uniqstr_new (type);
+ merge_function->type_declaration_location = declaration_loc;
+}
+
+/*--------------------------------------.
+| Free all merge-function definitions. |
+`--------------------------------------*/
-static inline void
-copy_at (FILE *fin, struct obstack *oout, int stack_offset)
+void
+free_merger_functions (void)
{
- int c;
-
- c = getc (fin);
- if (c == '$')
- {
- obstack_sgrow (oout, "yyloc");
- locations_flag = 1;
- }
- else if (isdigit (c) || c == '-')
- {
- int n;
-
- ungetc (c, fin);
- n = read_signed_integer (fin);
-
- obstack_fgrow1 (oout, "yylsp[%d]", n - stack_offset);
- locations_flag = 1;
- }
- else
+ merger_list *L0 = merge_functions;
+ while (L0)
{
- char buf[] = "@c";
- buf[1] = c;
- complain (_("%s is invalid"), quote (buf));
+ merger_list *L1 = L0->next;
+ free (L0);
+ L0 = L1;
}
}
-
+
/*-------------------------------------------------------------------.
-| FIN is pointing to a wannabee semantic value (i.e., a `$'). |
-| |
-| Possible inputs: $[]($|integer) |
+| Parse the input grammar into a one symbol_list structure. Each |
+| rule is represented by a sequence of symbols: the left hand side |
+| followed by the contents of the right hand side, followed by a |
+| null pointer instead of a symbol to terminate the rule. The next |
+| symbol is the lhs of the following rule. |
| |
-| Output to OOUT a reference to this semantic value. STACK_OFFSET is |
-| the number of values in the current rule so far, which says where |
-| to find `$0' with respect to the top of the stack. |
+| All actions are copied out, labelled by the rule number they apply |
+| to. |
`-------------------------------------------------------------------*/
-static inline void
-copy_dollar (FILE *fin, struct obstack *oout,
- symbol_list *rule, int stack_offset)
-{
- int c = getc (fin);
- const char *type_name = NULL;
-
- /* Get the type name if explicit. */
- if (c == '<')
- {
- read_type_name (fin);
- type_name = token_buffer;
- value_components_used = 1;
- c = getc (fin);
- }
-
- if (c == '$')
- {
- obstack_sgrow (oout, "yyval");
-
- if (!type_name)
- type_name = get_type_name (0, rule);
- if (type_name)
- obstack_fgrow1 (oout, ".%s", type_name);
- if (!type_name && typed)
- complain (_("$$ of `%s' has no declared type"),
- rule->sym->tag);
- }
- else if (isdigit (c) || c == '-')
- {
- int n;
- ungetc (c, fin);
- n = read_signed_integer (fin);
-
- if (!type_name && n > 0)
- type_name = get_type_name (n, rule);
-
- obstack_fgrow1 (oout, "yyvsp[%d]", n - stack_offset);
-
- if (type_name)
- obstack_fgrow1 (oout, ".%s", type_name);
- if (!type_name && typed)
- complain (_("$%d of `%s' has no declared type"),
- n, rule->sym->tag);
- }
- else
- {
- char buf[] = "$c";
- buf[1] = c;
- complain (_("%s is invalid"), quote (buf));
- }
-}
-
-/*-------------------------------------------------------------------.
-| Copy the contents of a `%{ ... %}' into the definitions file. The |
-| `%{' has already been read. Return after reading the `%}'. |
-`-------------------------------------------------------------------*/
+/* The (currently) last symbol of GRAMMAR. */
+static symbol_list *grammar_end = NULL;
-static void
-copy_definition (void)
+/* Append SYM to the grammar. */
+static symbol_list *
+grammar_symbol_append (symbol *sym, location loc)
{
- int c;
- /* -1 while reading a character if prev char was %. */
- int after_percent;
-
- if (!no_lines_flag)
- {
- obstack_fgrow2 (&attrs_obstack, muscle_find ("linef"),
- lineno, quotearg_style (c_quoting_style,
- muscle_find("filename")));
- }
-
- after_percent = 0;
-
- c = getc (finput);
+ symbol_list *p = symbol_list_sym_new (sym, loc);
- for (;;)
- {
- switch (c)
- {
- case '\n':
- obstack_1grow (&attrs_obstack, c);
- lineno++;
- break;
-
- case '%':
- after_percent = -1;
- break;
-
- case '\'':
- case '"':
- copy_string (finput, &attrs_obstack, c);
- break;
-
- case '/':
- copy_comment (finput, &attrs_obstack);
- break;
+ if (grammar_end)
+ grammar_end->next = p;
+ else
+ grammar = p;
- case EOF:
- fatal ("%s", _("unterminated `%{' definition"));
+ grammar_end = p;
- default:
- obstack_1grow (&attrs_obstack, c);
- }
+ /* A null SYM stands for an end of rule; it is not an actual
+ part of it. */
+ if (sym)
+ ++nritems;
- c = getc (finput);
-
- if (after_percent)
- {
- if (c == '}')
- return;
- obstack_1grow (&attrs_obstack, '%');
- }
- after_percent = 0;
- }
+ return p;
}
-
-/*-------------------------------------------------------------------.
-| Parse what comes after %token or %nterm. For %token, WHAT_IS is |
-| token_sym and WHAT_IS_NOT is nterm_sym. For %nterm, the arguments |
-| are reversed. |
-`-------------------------------------------------------------------*/
-
static void
-parse_token_decl (symbol_class what_is, symbol_class what_is_not)
+assign_named_ref (symbol_list *p, named_ref *name)
{
- token_t token = tok_undef;
- char *typename = NULL;
-
- /* The symbol being defined. */
- struct bucket *symbol = NULL;
+ symbol *sym = p->content.sym;
- /* After `%token' and `%nterm', any number of symbols maybe be
- defined. */
- for (;;)
+ if (name->id == sym->tag)
{
- int tmp_char = ungetc (skip_white_space (), finput);
-
- /* `%' (for instance from `%token', or from `%%' etc.) is the
- only valid means to end this declaration. */
- if (tmp_char == '%')
- return;
- if (tmp_char == EOF)
- fatal (_("Premature EOF after %s"), token_buffer);
-
- token = lex ();
- if (token == tok_comma)
- {
- symbol = NULL;
- continue;
- }
- if (token == tok_typename)
- {
- typename = xstrdup (token_buffer);
- value_components_used = 1;
- symbol = NULL;
- }
- else if (token == tok_identifier && *symval->tag == '\"' && symbol)
- {
- if (symval->alias)
- warn (_("symbol `%s' used more than once as a literal string"),
- symval->tag);
- else if (symbol->alias)
- warn (_("symbol `%s' given more than one literal string"),
- symbol->tag);
- else
- {
- symval->class = token_sym;
- symval->type_name = typename;
- symval->user_token_number = symbol->user_token_number;
- symbol->user_token_number = SALIAS;
- symval->alias = symbol;
- symbol->alias = symval;
- /* symbol and symval combined are only one symbol */
- nsyms--;
- }
- symbol = NULL;
- }
- else if (token == tok_identifier)
- {
- int oldclass = symval->class;
- symbol = symval;
-
- if (symbol->class == what_is_not)
- complain (_("symbol %s redefined"), symbol->tag);
- symbol->class = what_is;
- if (what_is == nterm_sym && oldclass != nterm_sym)
- symbol->value = nvars++;
-
- if (typename)
- {
- if (symbol->type_name == NULL)
- symbol->type_name = typename;
- else if (strcmp (typename, symbol->type_name) != 0)
- complain (_("type redeclaration for %s"), symbol->tag);
- }
- }
- else if (symbol && token == tok_number)
- {
- symbol->user_token_number = numval;
- }
- else
- {
- complain (_("`%s' is invalid in %s"),
- token_buffer,
- (what_is == token_sym) ? "%token" : "%nterm");
- skip_to_char ('%');
- }
+ warn_at (name->loc,
+ _("duplicated symbol name for %s ignored"),
+ quote (sym->tag));
+ named_ref_free (name);
}
-
-}
-
-
-/*------------------------------.
-| Parse what comes after %start |
-`------------------------------*/
-
-static void
-parse_start_decl (void)
-{
- if (start_flag)
- complain (_("multiple %s declarations"), "%start");
- if (lex () != tok_identifier)
- complain (_("invalid %s declaration"), "%start");
else
- {
- start_flag = 1;
- startval = symval;
- }
+ p->named_ref = name;
}
-/*-----------------------------------------------------------.
-| read in a %type declaration and record its information for |
-| get_type_name to access |
-`-----------------------------------------------------------*/
-
-static void
-parse_type_decl (void)
-{
- char *name;
-
- if (lex () != tok_typename)
- {
- complain ("%s", _("%type declaration has no "));
- skip_to_char ('%');
- return;
- }
-
- name = xstrdup (token_buffer);
-
- for (;;)
- {
- token_t t;
- int tmp_char = ungetc (skip_white_space (), finput);
-
- if (tmp_char == '%')
- return;
- if (tmp_char == EOF)
- fatal (_("Premature EOF after %s"), token_buffer);
-
- t = lex ();
-
- switch (t)
- {
-
- case tok_comma:
- case tok_semicolon:
- break;
-
- case tok_identifier:
- if (symval->type_name == NULL)
- symval->type_name = name;
- else if (strcmp (name, symval->type_name) != 0)
- complain (_("type redeclaration for %s"), symval->tag);
- break;
-
- default:
- complain (_("invalid %%type declaration due to item: %s"),
- token_buffer);
- skip_to_char ('%');
- }
- }
-}
+/* 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. |
+`----------------------------------------------*/
-/*----------------------------------------------------------------.
-| Read in a %left, %right or %nonassoc declaration and record its |
-| information. |
-`----------------------------------------------------------------*/
-
-static void
-parse_assoc_decl (associativity assoc)
+void
+grammar_current_rule_begin (symbol *lhs, location loc,
+ named_ref *lhs_name)
{
- char *name = NULL;
- int prev = 0;
-
- lastprec++; /* Assign a new precedence level, never 0. */
-
- for (;;)
- {
- token_t t;
- int tmp_char = ungetc (skip_white_space (), finput);
-
- if (tmp_char == '%')
- return;
- if (tmp_char == EOF)
- fatal (_("Premature EOF after %s"), token_buffer);
-
- t = lex ();
-
- switch (t)
- {
- case tok_typename:
- name = xstrdup (token_buffer);
- break;
-
- case tok_comma:
- break;
-
- case tok_identifier:
- if (symval->prec != 0)
- complain (_("redefining precedence of %s"), symval->tag);
- symval->prec = lastprec;
- symval->assoc = assoc;
- if (symval->class == nterm_sym)
- complain (_("symbol %s redefined"), symval->tag);
- symval->class = token_sym;
- if (name)
- { /* record the type, if one is specified */
- if (symval->type_name == NULL)
- symval->type_name = name;
- else if (strcmp (name, symval->type_name) != 0)
- complain (_("type redeclaration for %s"), symval->tag);
- }
- break;
-
- case tok_number:
- if (prev == tok_identifier)
- {
- symval->user_token_number = numval;
- }
- else
- {
- complain (_
- ("invalid text (%s) - number should be after identifier"),
-token_buffer);
- skip_to_char ('%');
- }
- break;
-
- case tok_semicolon:
- return;
-
- default:
- complain (_("unexpected item: %s"), token_buffer);
- skip_to_char ('%');
- }
-
- prev = t;
- }
-}
-
+ symbol_list* p;
+ /* Start a new rule and record its lhs. */
+ ++nrules;
+ previous_rule_end = grammar_end;
-/*--------------------------------------------------------------.
-| Copy the union declaration into the stype muscle |
-| (and fdefines), where it is made into the definition of |
-| YYSTYPE, the type of elements of the parser value stack. |
-`--------------------------------------------------------------*/
+ p = grammar_symbol_append (lhs, loc);
+ if (lhs_name)
+ assign_named_ref (p, named_ref_copy (lhs_name));
-static void
-parse_union_decl (void)
-{
- int c;
- int count = 0;
- bool done = FALSE;
- struct obstack union_obstack;
- if (typed)
- complain (_("multiple %s declarations"), "%union");
-
- typed = 1;
-
- obstack_init (&union_obstack);
- obstack_sgrow (&union_obstack, "union");
+ current_rule = grammar_end;
- while (!done)
+ /* Mark the rule's lhs as a nonterminal if not already so. */
+ if (lhs->class == unknown_sym)
{
- c = xgetc (finput);
-
- /* If C contains '/', it is output by copy_comment (). */
- if (c != '/')
- obstack_1grow (&union_obstack, c);
-
- switch (c)
- {
- case '\n':
- lineno++;
- break;
-
- case '/':
- copy_comment (finput, &union_obstack);
- break;
-
- case '{':
- count++;
- break;
-
- case '}':
- /* FIXME: Errr. How could this happen???. --akim */
- if (count == 0)
- complain (_("unmatched %s"), "`}'");
- count--;
- if (!count)
- done = TRUE;
- break;
- }
+ lhs->class = nterm_sym;
+ lhs->number = nvars;
+ ++nvars;
}
-
- /* JF don't choke on trailing semi */
- c = skip_white_space ();
- if (c != ';')
- ungetc (c, finput);
- obstack_1grow (&union_obstack, 0);
- muscle_insert ("stype", obstack_finish (&union_obstack));
-}
-
-
-/*-------------------------------------------------------.
-| Parse the declaration %expect N which says to expect N |
-| shift-reduce conflicts. |
-`-------------------------------------------------------*/
-
-static void
-parse_expect_decl (void)
-{
- int c = skip_white_space ();
- ungetc (c, finput);
-
- if (!isdigit (c))
- complain (_("argument of %%expect is not an integer"));
- else
- expected_conflicts = read_signed_integer (finput);
+ else if (lhs->class == token_sym)
+ complain_at (loc, _("rule given for %s, which is a token"), lhs->tag);
}
-/*-------------------------------------------------------------------.
-| Parse what comes after %thong. the full syntax is |
-| |
-| %thong token number literal |
-| |
-| the or number may be omitted. The number specifies the |
-| user_token_number. |
-| |
-| Two symbols are entered in the table, one for the token symbol and |
-| one for the literal. Both are given the , if any, from the |
-| declaration. The ->user_token_number of the first is SALIAS and |
-| the ->user_token_number of the second is set to the number, if |
-| any, from the declaration. The two symbols are linked via |
-| pointers in their ->alias fields. |
-| |
-| During OUTPUT_DEFINES_TABLE, the symbol is reported thereafter, |
-| only the literal string is retained it is the literal string that |
-| is output to yytname |
-`-------------------------------------------------------------------*/
+/*----------------------------------------------------------------------.
+| 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 void
-parse_thong_decl (void)
+static bool
+symbol_should_be_used (symbol_list const *s, bool *midrule_warning)
{
- token_t token;
- struct bucket *symbol;
- char *typename = 0;
- int usrtoknum = SUNDEF;
-
- token = lex (); /* fetch typename or first token */
- if (token == tok_typename)
- {
- typename = xstrdup (token_buffer);
- value_components_used = 1;
- token = lex (); /* fetch first token */
- }
-
- /* process first token */
-
- if (token != tok_identifier)
+ 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))
{
- complain (_("unrecognized item %s, expected an identifier"),
- token_buffer);
- skip_to_char ('%');
- return;
+ *midrule_warning = true;
+ return true;
}
- symval->class = token_sym;
- symval->type_name = typename;
- symval->user_token_number = SALIAS;
- symbol = symval;
-
- token = lex (); /* get number or literal string */
-
- if (token == tok_number)
- {
- usrtoknum = numval;
- token = lex (); /* okay, did number, now get literal */
- }
-
- /* process literal string token */
-
- if (token != tok_identifier || *symval->tag != '\"')
- {
- complain (_("expected string constant instead of %s"), token_buffer);
- skip_to_char ('%');
- return;
- }
- symval->class = token_sym;
- symval->type_name = typename;
- symval->user_token_number = usrtoknum;
-
- symval->alias = symbol;
- symbol->alias = symval;
-
- /* symbol and symval combined are only one symbol. */
- nsyms--;
+ return false;
}
+/*----------------------------------------------------------------.
+| Check that the rule R is properly defined. For instance, there |
+| should be no type clash on the default action. |
+`----------------------------------------------------------------*/
+
static void
-parse_muscle_decl (void)
+grammar_rule_check (const symbol_list *r)
{
- int ch = ungetc (skip_white_space (), finput);
- char* muscle_key;
- char* muscle_value;
+ /* Type check.
- /* Read key. */
- if (!isalpha (ch) && ch != '_')
- {
- complain (_("invalid %s declaration"), "%define");
- skip_to_char ('%');
- return;
- }
- copy_identifier (finput, &muscle_obstack);
- obstack_1grow (&muscle_obstack, 0);
- muscle_key = obstack_finish (&muscle_obstack);
+ If there is an action, then there is nothing we can do: the user
+ is allowed to shoot herself in the foot.
- /* Read value. */
- ch = skip_white_space ();
- if (ch != '"')
+ Don't worry about the default action if $$ is untyped, since $$'s
+ value can't be used. */
+ if (!r->action_props.code && r->content.sym->type_name)
{
- ungetc (ch, finput);
- if (ch != EOF)
+ symbol *first_rhs = r->next->content.sym;
+ /* If $$ is being set in default way, report if any type mismatch. */
+ if (first_rhs)
{
- complain (_("invalid %s declaration"), "%define");
- skip_to_char ('%');
- return;
+ 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 $$ but we need one. */
else
- fatal (_("Premature EOF after %s"), "\"");
- }
- copy_string2 (finput, &muscle_obstack, '"', 0);
- obstack_1grow (&muscle_obstack, 0);
- muscle_value = obstack_finish (&muscle_obstack);
-
- /* Store the (key, value) pair in the environment. */
- muscle_insert (muscle_key, muscle_value);
-}
-
-
-
-/*---------------------------------.
-| Parse a double quoted parameter. |
-`---------------------------------*/
-
-static const char *
-parse_dquoted_param (const char *from)
-{
- struct obstack param_obstack;
- const char *param = NULL;
- int c;
-
- obstack_init (¶m_obstack);
- c = skip_white_space ();
-
- if (c != '"')
- {
- complain (_("invalid %s declaration"), from);
- ungetc (c, finput);
- skip_to_char ('%');
- return NULL;
+ warn_at (r->location,
+ _("empty rule for typed nonterminal, and no action"));
}
- while ((c = literalchar ()) != '"')
- obstack_1grow (¶m_obstack, c);
-
- obstack_1grow (¶m_obstack, '\0');
- param = obstack_finish (¶m_obstack);
-
- if (c != '"' || strlen (param) == 0)
- {
- complain (_("invalid %s declaration"), from);
- if (c != '"')
- ungetc (c, finput);
- skip_to_char ('%');
- return NULL;
- }
+ /* Check that symbol values that should be used are in fact used. */
+ {
+ symbol_list const *l = r;
+ int n = 0;
+ for (; l && l->content.sym; l = l->next, ++n)
+ {
+ bool midrule_warning = false;
+ if (!l->action_props.is_value_used
+ && symbol_should_be_used (l, &midrule_warning)
+ /* The default action, $$ = $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: $$"));
+ }
+ }
+ }
- return param;
+ /* 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);
}
-/*----------------------------------.
-| Parse what comes after %skeleton. |
-`----------------------------------*/
-
-static void
-parse_skel_decl (void)
-{
- skeleton = parse_dquoted_param ("%skeleton");
-}
-/*----------------------------------------------------------------.
-| Read from finput until `%%' is seen. Discard the `%%'. Handle |
-| any `%' declarations, and copy the contents of any `%{ ... %}' |
-| groups to ATTRS_OBSTACK. |
-`----------------------------------------------------------------*/
+/*-------------------------------------.
+| End the currently being grown rule. |
+`-------------------------------------*/
-static void
-read_declarations (void)
+void
+grammar_current_rule_end (location loc)
{
- for (;;)
- {
- int c = skip_white_space ();
-
- if (c == '%')
- {
- token_t tok = parse_percent_token ();
-
- switch (tok)
- {
- case tok_two_percents:
- return;
-
- case tok_percent_left_curly:
- copy_definition ();
- break;
-
- case tok_token:
- parse_token_decl (token_sym, nterm_sym);
- break;
-
- case tok_nterm:
- parse_token_decl (nterm_sym, token_sym);
- break;
-
- case tok_type:
- parse_type_decl ();
- break;
-
- case tok_start:
- parse_start_decl ();
- break;
-
- case tok_union:
- parse_union_decl ();
- break;
-
- case tok_expect:
- parse_expect_decl ();
- break;
-
- case tok_thong:
- parse_thong_decl ();
- break;
-
- case tok_left:
- parse_assoc_decl (left_assoc);
- break;
-
- case tok_right:
- parse_assoc_decl (right_assoc);
- break;
-
- case tok_nonassoc:
- parse_assoc_decl (non_assoc);
- break;
-
- case tok_define:
- parse_muscle_decl ();
- break;
-
- case tok_skel:
- parse_skel_decl ();
- break;
-
- case tok_noop:
- break;
-
- case tok_stropt:
- case tok_intopt:
- case tok_obsolete:
- abort ();
- break;
-
- case tok_illegal:
- default:
- complain (_("unrecognized: %s"), token_buffer);
- skip_to_char ('%');
- }
- }
- else if (c == EOF)
- fatal (_("no input grammar"));
- else
- {
- char buf[] = "c";
- buf[0] = c;
- complain (_("unknown character: %s"), quote (buf));
- skip_to_char ('%');
- }
- }
+ /* Put an empty link in the list to mark the end of this rule */
+ grammar_symbol_append (NULL, grammar_end->location);
+ current_rule->location = loc;
}
-
-/*-------------------------------------------------------------------.
-| Assuming that a `{' has just been seen, copy everything up to the |
-| matching `}' into the actions file. STACK_OFFSET is the number of |
-| values in the current rule so far, which says where to find `$0' |
-| with respect to the top of the stack. |
-`-------------------------------------------------------------------*/
-
-static void
-copy_action (symbol_list *rule, int stack_offset)
-{
- int c;
- int count;
-
- /* offset is always 0 if parser has already popped the stack pointer */
- if (semantic_parser)
- stack_offset = 0;
-
- count = 1;
- c = getc (finput);
- while (count > 0)
- {
- while (c != '}')
- {
- switch (c)
- {
- case '\n':
- obstack_1grow (&action_obstack, c);
- lineno++;
- break;
-
- case '{':
- obstack_1grow (&action_obstack, c);
- count++;
- break;
-
- case '\'':
- case '"':
- copy_string (finput, &action_obstack, c);
- break;
-
- case '/':
- copy_comment (finput, &action_obstack);
- break;
-
- case '$':
- copy_dollar (finput, &action_obstack,
- rule, stack_offset);
- break;
-
- case '@':
- copy_at (finput, &action_obstack,
- stack_offset);
- break;
-
- case EOF:
- fatal (_("unmatched %s"), "`{'");
-
- default:
- obstack_1grow (&action_obstack, c);
- }
-
- c = getc (finput);
- }
-
- /* above loop exits when c is '}' */
-
- if (--count)
- {
- obstack_1grow (&action_obstack, c);
- c = getc (finput);
- }
- }
- obstack_1grow (&action_obstack, '\0');
- rule->action = obstack_finish (&action_obstack);
- rule->action_line = lineno;
-}
-
/*-------------------------------------------------------------------.
-| After `%guard' is seen in the input file, copy the actual guard |
-| into the guards file. If the guard is followed by an action, copy |
-| that into the actions file. STACK_OFFSET is the number of values |
-| in the current rule so far, which says where to find `$0' with |
-| respect to the top of the stack, for the simple parser in which |
-| the stack is not popped until after the guard is run. |
+| 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. |
`-------------------------------------------------------------------*/
-static void
-copy_guard (symbol_list *rule, int stack_offset)
-{
- int c;
- int count;
- int brace_flag = 0;
-
- /* offset is always 0 if parser has already popped the stack pointer */
- if (semantic_parser)
- stack_offset = 0;
-
- obstack_fgrow1 (&guard_obstack, "\ncase %d:\n", nrules);
- if (!no_lines_flag)
- obstack_fgrow2 (&guard_obstack, muscle_find ("linef"),
- lineno, quotearg_style (c_quoting_style,
- muscle_find ("filename")));
- obstack_1grow (&guard_obstack, '{');
-
- count = 0;
- c = getc (finput);
-
- while (brace_flag ? (count > 0) : (c != ';'))
- {
- switch (c)
- {
- case '\n':
- obstack_1grow (&guard_obstack, c);
- lineno++;
- break;
-
- case '{':
- obstack_1grow (&guard_obstack, c);
- brace_flag = 1;
- count++;
- break;
-
- case '}':
- obstack_1grow (&guard_obstack, c);
- if (count > 0)
- count--;
- else
- {
- complain (_("unmatched %s"), "`}'");
- c = getc (finput); /* skip it */
- }
- break;
-
- case '\'':
- case '"':
- copy_string (finput, &guard_obstack, c);
- break;
-
- case '/':
- copy_comment (finput, &guard_obstack);
- break;
-
- case '$':
- copy_dollar (finput, &guard_obstack, rule, stack_offset);
- break;
-
- case '@':
- copy_at (finput, &guard_obstack, stack_offset);
- break;
-
- case EOF:
- fatal ("%s", _("unterminated %guard clause"));
-
- default:
- obstack_1grow (&guard_obstack, c);
- }
-
- if (c != '}' || count != 0)
- c = getc (finput);
- }
-
- c = skip_white_space ();
-
- obstack_sgrow (&guard_obstack, ";\n break;}");
- if (c == '{')
- copy_action (rule, stack_offset);
- else if (c == '=')
- {
- c = getc (finput); /* why not skip_white_space -wjh */
- if (c == '{')
- copy_action (rule, stack_offset);
- }
+void
+grammar_midrule_action (void)
+{
+ /* Since the action was written out with this rule's number, we must
+ give the new rule this number by inserting the new rule before
+ it. */
+
+ /* 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 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);
+ code_props_none_init (¤t_rule->action_props);
+
+ if (previous_rule_end)
+ previous_rule_end->next = midrule;
else
- ungetc (c, finput);
-}
-
-
-/*-------------------------------------------------------------------.
-| Generate a dummy symbol, a nonterminal, whose name cannot conflict |
-| with the user's names. |
-`-------------------------------------------------------------------*/
-
-static bucket *
-gensym (void)
-{
- /* Incremented for each generated symbol */
- static int gensym_count = 0;
- static char buf[256];
-
- bucket *sym;
-
- sprintf (buf, "@%d", ++gensym_count);
- token_buffer = buf;
- sym = getsym (token_buffer);
- sym->class = nterm_sym;
- sym->value = nvars++;
- return sym;
-}
-
-/*-------------------------------------------------------------------.
-| Parse the input grammar into a one symbol_list structure. Each |
-| rule is represented by a sequence of symbols: the left hand side |
-| followed by the contents of the right hand side, followed by a |
-| null pointer instead of a symbol to terminate the rule. The next |
-| symbol is the lhs of the following rule. |
-| |
-| All guards and actions are copied out to the appropriate files, |
-| 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. |
-`-------------------------------------------------------------------*/
-
-static void
-readgram (void)
-{
- token_t t;
- bucket *lhs = NULL;
- symbol_list *p = NULL;
- symbol_list *p1 = NULL;
- bucket *bp;
-
- /* Points to first symbol_list of current rule. its symbol is the
- lhs of the rule. */
- symbol_list *crule = NULL;
- /* Points to the symbol_list preceding crule. */
- symbol_list *crule1 = NULL;
-
- t = lex ();
-
- while (t != tok_two_percents && t != tok_eof)
- if (t == tok_identifier || t == tok_bar)
- {
- int action_flag = 0;
- /* Number of symbols in rhs of this rule so far */
- int rulelength = 0;
- int xactions = 0; /* JF for error checking */
- bucket *first_rhs = 0;
-
- if (t == tok_identifier)
- {
- lhs = symval;
-
- if (!start_flag)
- {
- startval = lhs;
- start_flag = 1;
- }
-
- t = lex ();
- if (t != tok_colon)
- {
- complain (_("ill-formed rule: initial symbol not followed by colon"));
- unlex (t);
- }
- }
-
- if (nrules == 0 && t == tok_bar)
- {
- complain (_("grammar starts with vertical bar"));
- lhs = symval; /* BOGUS: use a random symval */
- }
- /* start a new rule and record its lhs. */
-
- nrules++;
- nitems++;
-
- p = symbol_list_new (lhs);
-
- crule1 = p1;
- if (p1)
- p1->next = p;
- else
- grammar = p;
-
- p1 = p;
- crule = p;
-
- /* mark the rule's lhs as a nonterminal if not already so. */
-
- if (lhs->class == unknown_sym)
- {
- lhs->class = nterm_sym;
- lhs->value = nvars;
- nvars++;
- }
- else if (lhs->class == token_sym)
- complain (_("rule given for %s, which is a token"), lhs->tag);
-
- /* read the rhs of the rule. */
-
- for (;;)
- {
- t = lex ();
- if (t == tok_prec)
- {
- t = lex ();
- crule->ruleprec = symval;
- t = lex ();
- }
-
- if (!(t == tok_identifier || t == tok_left_curly))
- break;
-
- /* If next token is an identifier, see if a colon follows it.
- If one does, exit this rule now. */
- if (t == tok_identifier)
- {
- bucket *ssave;
- token_t t1;
-
- ssave = symval;
- t1 = lex ();
- unlex (t1);
- symval = ssave;
- if (t1 == tok_colon)
- break;
-
- if (!first_rhs) /* JF */
- first_rhs = symval;
- /* Not followed by colon =>
- process as part of this rule's rhs. */
- }
-
- /* If we just passed an action, that action was in the middle
- of a rule, so make a dummy rule to reduce it to a
- non-terminal. */
- if (action_flag)
- {
- /* Since the action was written out with this rule's
- number, we must give the new rule this number by
- inserting the new rule before it. */
-
- /* Make a dummy nonterminal, a gensym. */
- bucket *sdummy = gensym ();
-
- /* Make a new rule, whose body is empty, before the
- current one, so that the action just read can
- belong to it. */
- nrules++;
- nitems++;
- p = symbol_list_new (sdummy);
- /* Attach its lineno to that of the host rule. */
- p->line = crule->line;
- if (crule1)
- crule1->next = p;
- else
- grammar = p;
- /* End of the rule. */
- crule1 = symbol_list_new (NULL);
- crule1->next = crule;
-
- p->next = crule1;
-
- /* Insert the dummy generated by that rule into this
- rule. */
- nitems++;
- p = symbol_list_new (sdummy);
- p1->next = p;
- p1 = p;
-
- action_flag = 0;
- }
-
- if (t == tok_identifier)
- {
- nitems++;
- p = symbol_list_new (symval);
- p1->next = p;
- p1 = p;
- }
- else /* handle an action. */
- {
- copy_action (crule, rulelength);
- action_flag = 1;
- xactions++; /* JF */
- }
- rulelength++;
- } /* end of read rhs of rule */
-
- /* Put an empty link in the list to mark the end of this rule */
- p = symbol_list_new (NULL);
- p1->next = p;
- p1 = p;
-
- if (t == tok_prec)
- {
- complain (_("two @prec's in a row"));
- t = lex ();
- crule->ruleprec = symval;
- t = lex ();
- }
- if (t == tok_guard)
- {
- if (!semantic_parser)
- complain (_("%%guard present but %%semantic_parser not specified"));
-
- copy_guard (crule, rulelength);
- t = lex ();
- }
- else if (t == tok_left_curly)
- {
- /* This case never occurs -wjh */
- if (action_flag)
- complain (_("two actions at end of one rule"));
- copy_action (crule, rulelength);
- action_flag = 1;
- xactions++; /* -wjh */
- t = lex ();
- }
- /* If $$ is being set in default way, report if any type
- mismatch. */
- else if (!xactions
- && first_rhs && lhs->type_name != first_rhs->type_name)
- {
- if (lhs->type_name == 0
- || first_rhs->type_name == 0
- || strcmp (lhs->type_name, first_rhs->type_name))
- complain (_("type clash (`%s' `%s') on default action"),
- lhs->type_name ? lhs->type_name : "",
- first_rhs->type_name ? first_rhs->type_name : "");
- }
- /* Warn if there is no default for $$ but we need one. */
- else if (!xactions && !first_rhs && lhs->type_name != 0)
- complain (_("empty rule for typed nonterminal, and no action"));
- if (t == tok_semicolon)
- t = lex ();
- }
- else
- {
- complain (_("invalid input: %s"), quote (token_buffer));
- t = lex ();
- }
+ grammar = midrule;
+ /* End the dummy's rule. */
+ midrule->next = symbol_list_sym_new (NULL, dummy_location);
+ midrule->next->next = current_rule;
- /* grammar has been read. Do some checking */
-
- if (nsyms > MAXSHORT)
- fatal (_("too many symbols (tokens plus nonterminals); maximum %d"),
- MAXSHORT);
- if (nrules == 0)
- fatal (_("no rules in the input grammar"));
-
- /* Report any undefined symbols and consider them nonterminals. */
+ previous_rule_end = midrule->next;
- for (bp = firstsymbol; bp; bp = bp->next)
- if (bp->class == unknown_sym)
- {
- complain (_
- ("symbol %s is used, but is not defined as a token and has no rules"),
- bp->tag);
- bp->class = nterm_sym;
- bp->value = nvars++;
- }
-
- ntokens = nsyms - nvars;
+ /* 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);
}
-/* At the end of the grammar file, some C source code must
- be stored. It is going to be associated to the epilogue
- directive. */
-static void
-read_additionnal_code (void)
-{
- char c;
- struct obstack el_obstack;
-
- obstack_init (&el_obstack);
-
- if (!no_lines_flag)
- {
- obstack_fgrow2 (&el_obstack, muscle_find ("linef"),
- lineno, quotearg_style (c_quoting_style,
- muscle_find("filename")));
- }
+/* Set the precedence symbol of the current rule to PRECSYM. */
- while ((c = getc (finput)) != EOF)
- obstack_1grow (&el_obstack, c);
+void
+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_at (loc, _("only one %s allowed per rule"), "%prec");
+ current_rule->ruleprec = precsym;
+}
+
+/* Attach dynamic precedence DPREC to the current rule. */
- obstack_1grow (&el_obstack, 0);
- muscle_insert ("epilogue", obstack_finish (&el_obstack));
+void
+grammar_current_rule_dprec_set (int dprec, location loc)
+{
+ 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;
}
-
-/*------------------------------------------------------------------.
-| Set TOKEN_TRANSLATIONS. Check that no two symbols share the same |
-| number. |
-`------------------------------------------------------------------*/
+/* Attach a merge function NAME with argument type TYPE to current
+ rule. */
-static void
-token_translations_init (void)
+void
+grammar_current_rule_merge_set (uniqstr name, location loc)
{
- bucket *bp = NULL;
- int i;
-
- token_translations = XCALLOC (short, max_user_token_number + 1);
-
- /* Initialize all entries for literal tokens to 2, the internal
- token number for $undefined., which represents all invalid
- inputs. */
- for (i = 0; i <= max_user_token_number; i++)
- token_translations[i] = 2;
-
- for (bp = firstsymbol; bp; bp = bp->next)
- {
- /* Non-terminal? */
- if (bp->value >= ntokens)
- continue;
- /* A token string alias? */
- if (bp->user_token_number == SALIAS)
- continue;
-
- assert (bp->user_token_number != SUNDEF);
-
- /* A token which translation has already been set? */
- if (token_translations[bp->user_token_number] != 2)
- complain (_("tokens %s and %s both assigned number %d"),
- tags[token_translations[bp->user_token_number]],
- bp->tag, bp->user_token_number);
- token_translations[bp->user_token_number] = bp->value;
- }
+ 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 SYM to the current rule. If needed, move the previous
+ action as a mid-rule action. */
-/*------------------------------------------------------------------.
-| Assign symbol numbers, and write definition of token names into |
-| FDEFINES. Set up vectors TAGS and SPREC of names and precedences |
-| of symbols. |
-`------------------------------------------------------------------*/
-
-static void
-packsymbols (void)
+void
+grammar_current_rule_symbol_append (symbol *sym, location loc,
+ named_ref *name)
{
- bucket *bp = NULL;
- int tokno = 1;
- int last_user_token_number;
- static char DOLLAR[] = "$";
-
- tags = XCALLOC (char *, nsyms + 1);
- user_toknums = XCALLOC (short, nsyms + 1);
-
- sprec = XCALLOC (short, nsyms);
- sassoc = XCALLOC (short, nsyms);
-
- /* The EOF token. */
- tags[0] = DOLLAR;
- user_toknums[0] = 0;
-
- max_user_token_number = 256;
- last_user_token_number = 256;
-
- for (bp = firstsymbol; bp; bp = bp->next)
- {
- if (bp->class == nterm_sym)
- {
- bp->value += ntokens;
- }
- else if (bp->alias)
- {
- /* this symbol and its alias are a single token defn.
- allocate a tokno, and assign to both check agreement of
- ->prec and ->assoc fields and make both the same */
- if (bp->value == 0)
- bp->value = bp->alias->value = tokno++;
-
- if (bp->prec != bp->alias->prec)
- {
- if (bp->prec != 0 && bp->alias->prec != 0
- && bp->user_token_number == SALIAS)
- complain (_("conflicting precedences for %s and %s"),
- bp->tag, bp->alias->tag);
- if (bp->prec != 0)
- bp->alias->prec = bp->prec;
- else
- bp->prec = bp->alias->prec;
- }
-
- if (bp->assoc != bp->alias->assoc)
- {
- if (bp->assoc != 0 && bp->alias->assoc != 0
- && bp->user_token_number == SALIAS)
- complain (_("conflicting assoc values for %s and %s"),
- bp->tag, bp->alias->tag);
- if (bp->assoc != 0)
- bp->alias->assoc = bp->assoc;
- else
- bp->assoc = bp->alias->assoc;
- }
-
- if (bp->user_token_number == SALIAS)
- continue; /* do not do processing below for SALIASs */
-
- }
- else /* bp->class == token_sym */
- {
- bp->value = tokno++;
- }
-
- if (bp->class == token_sym)
- {
- if (bp->user_token_number == SUNDEF)
- bp->user_token_number = ++last_user_token_number;
- if (bp->user_token_number > max_user_token_number)
- max_user_token_number = bp->user_token_number;
- }
-
- tags[bp->value] = bp->tag;
- user_toknums[bp->value] = bp->user_token_number;
- sprec[bp->value] = bp->prec;
- sassoc[bp->value] = bp->assoc;
- }
-
- token_translations_init ();
-
- error_token_number = errtoken->value;
-
- if (startval->class == unknown_sym)
- fatal (_("the start symbol %s is undefined"), startval->tag);
- else if (startval->class == token_sym)
- fatal (_("the start symbol %s is a token"), startval->tag);
-
- start_symbol = startval->value;
+ 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. */
-/*---------------------------------------------------------------.
-| Save the definition of token names in the `TOKENDEFS' muscle. |
-`---------------------------------------------------------------*/
-
-static void
-symbols_save (void)
+void
+grammar_current_rule_action_append (const char *action, location loc,
+ named_ref *name)
{
- struct obstack tokendefs;
- bucket *bp;
- char *cp, *symbol;
- char c;
- obstack_init (&tokendefs);
-
- for (bp = firstsymbol; bp; bp = bp->next)
- {
- symbol = bp->tag; /* get symbol */
-
- if (bp->value >= ntokens)
- continue;
- if (bp->user_token_number == SALIAS)
- continue;
- if ('\'' == *symbol)
- continue; /* skip literal character */
- if (bp == errtoken)
- continue; /* skip error token */
- if ('\"' == *symbol)
- {
- /* use literal string only if given a symbol with an alias */
- if (bp->alias)
- symbol = bp->alias->tag;
- else
- continue;
- }
-
- /* Don't #define nonliteral tokens whose names contain periods. */
- cp = symbol;
- while ((c = *cp++) && c != '.');
- if (c != '\0')
- continue;
-
- obstack_fgrow2 (&tokendefs, "# define %s\t%d\n",
- symbol, bp->user_token_number);
- if (semantic_parser)
- /* FIXME: This is probably wrong, and should be just as
- above. --akim. */
- obstack_fgrow2 (&tokendefs, "# define T%s\t%d\n", symbol, bp->value);
- }
-
- obstack_1grow (&tokendefs, 0);
- muscle_insert ("tokendef", xstrdup (obstack_finish (&tokendefs)));
- obstack_free (&tokendefs, NULL);
+ if (current_rule->action_props.code)
+ grammar_midrule_action ();
+ /* 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);
}
-
+
/*---------------------------------------------------------------.
| Convert the rules into the representation using RRHS, RLHS and |
-| RITEMS. |
+| RITEM. |
`---------------------------------------------------------------*/
static void
packgram (void)
{
- int itemno;
- int ruleno;
- symbol_list *p;
+ unsigned int itemno = 0;
+ rule_number ruleno = 0;
+ symbol_list *p = grammar;
- ritem = XCALLOC (short, nitems + 1);
- rule_table = 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)
{
- bucket *ruleprec = p->ruleprec;
- rule_table[ruleno].lhs = p->sym->value;
- rule_table[ruleno].rhs = itemno;
- rule_table[ruleno].line = p->line;
- rule_table[ruleno].useful = TRUE;
- rule_table[ruleno].action = p->action;
- rule_table[ruleno].action_line = p->action_line;
-
- p = p->next;
- while (p && p->sym)
+ 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->content.sym;
+ rules[ruleno].rhs = ritem + itemno;
+ 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;
+
+ /* 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)
{
- ritem[itemno++] = p->sym->value;
+ ++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 the last token in it. */
- if (p->sym->class == token_sym)
- {
- rule_table[ruleno].prec = p->sym->prec;
- rule_table[ruleno].assoc = p->sym->assoc;
- }
- if (p)
- p = p->next;
+ 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)
{
- rule_table[ruleno].prec = ruleprec->prec;
- rule_table[ruleno].assoc = ruleprec->assoc;
- rule_table[ruleno].precsym = ruleprec->value;
+ rules[ruleno].precsym = ruleprec;
+ rules[ruleno].prec = ruleprec;
}
-
- ritem[itemno++] = -ruleno;
- ruleno++;
+ /* 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;
}
- ritem[itemno] = 0;
+ aver (itemno == nritems);
- if (trace_flag)
+ if (trace_flag & trace_sets)
ritem_print (stderr);
}
-/*-------------------------------------------------------------------.
-| Read in the grammar specification and record it in the format |
-| described in gram.h. All guards are copied into the GUARD_OBSTACK |
-| and all actions into ACTION_OBSTACK, in each case forming the body |
-| of a C function (YYGUARD or YYACTION) which contains a switch |
-| statement to decide which guard or action to execute. |
-`-------------------------------------------------------------------*/
+/*------------------------------------------------------------------.
+| Read in the grammar specification and record it in the format |
+| described in gram.h. All actions are copied into ACTION_OBSTACK, |
+| in each case forming the body of a C function (YYACTION) which |
+| contains a switch statement to decide which action to execute. |
+`------------------------------------------------------------------*/
void
reader (void)
{
- start_flag = 0;
- startval = NULL; /* start symbol not specified yet. */
+ /* Initialize the symbol table. */
+ symbols_new ();
- nsyms = 1;
- nvars = 0;
- nrules = 0;
- nitems = 0;
+ /* Construct the accept symbol. */
+ accept = symbol_get ("$accept", empty_location);
+ accept->class = nterm_sym;
+ accept->number = nvars++;
- typed = 0;
- lastprec = 0;
+ /* Construct the error token */
+ errtoken = symbol_get ("error", empty_location);
+ errtoken->class = token_sym;
+ errtoken->number = ntokens++;
- semantic_parser = 0;
- pure_parser = 0;
+ /* Construct a token that represents all undefined literal tokens.
+ It is always token number 2. */
+ undeftoken = symbol_get ("$undefined", empty_location);
+ undeftoken->class = token_sym;
+ undeftoken->number = ntokens++;
- grammar = NULL;
+ gram_in = xfopen (grammar_file, "r");
- lex_init ();
- lineno = 1;
+ gram__flex_debug = trace_flag & trace_scan;
+ gram_debug = trace_flag & trace_parse;
+ gram_scanner_initialize ();
+ gram_parse ();
+ prepare_percent_define_front_end_variables ();
- /* Initialize the muscle obstack. */
- obstack_init (&muscle_obstack);
+ if (! complaint_issued)
+ check_and_convert_grammar ();
- /* Initialize the symbol table. */
- tabinit ();
+ xfclose (gram_in);
+}
- /* Construct the error token */
- errtoken = getsym ("error");
- errtoken->class = token_sym;
- errtoken->user_token_number = 256; /* Value specified by POSIX. */
+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 (0 != strcmp (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);
+ }
+}
- /* Construct a token that represents all undefined literal tokens.
- It is always token number 2. */
- undeftoken = getsym ("$undefined.");
- undeftoken->class = token_sym;
- undeftoken->user_token_number = 2;
- /* Initialize the obstacks. */
- obstack_init (&action_obstack);
- obstack_init (&attrs_obstack);
- obstack_init (&guard_obstack);
- obstack_init (&output_obstack);
+/*-------------------------------------------------------------.
+| Check the grammar that has just been read, and convert it to |
+| internal form. |
+`-------------------------------------------------------------*/
- finput = xfopen (infile, "r");
+static void
+check_and_convert_grammar (void)
+{
+ /* Grammar has been read. Do some checking. */
+ if (nrules == 0)
+ fatal (_("no rules in the input grammar"));
- /* Read the declaration section. Copy %{ ... %} groups to
- TABLE_OBSTACK and FDEFINES file. Also notice any %token, %left,
- etc. found there. */
- read_declarations ();
- /* Read in the grammar, build grammar in list form. Write out
- guards and actions. */
- readgram ();
- /* Some C code is given at the end of the grammar file. */
- read_additionnal_code ();
+ /* If the user did not define her ENDTOKEN, do it now. */
+ if (!endtoken)
+ {
+ endtoken = symbol_get ("$end", empty_location);
+ endtoken->class = token_sym;
+ endtoken->number = 0;
+ /* Value specified by POSIX. */
+ endtoken->user_token_number = 0;
+ }
- lex_free ();
- xfclose (finput);
+ /* Report any undefined symbols and consider them nonterminals. */
+ symbols_check_defined ();
+
+ /* Find the start symbol if no %start. */
+ if (!start_flag)
+ {
+ 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, whose line is that of the first rule
+ (not that of the start symbol):
+
+ accept: %start EOF. */
+ {
+ 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;
+ }
+
+ aver (nsyms <= SYMBOL_NUMBER_MAXIMUM && nsyms == ntokens + nvars);
/* Assign the symbols their symbol numbers. Write #defines for the
token symbols into FDEFINES if requested. */
- packsymbols ();
- /* Save them. */
- symbols_save ();
+ 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. */
+ symbol_list_free (grammar);
}