sym->value = nvars++;
return sym;
}
-
-#if 0
-/*------------------------------------------------------------------.
-| read in a %type declaration and record its information for |
-| get_type_name to access. This is unused. It is only called from |
-| the #if 0 part of readgram |
-`------------------------------------------------------------------*/
-
-static int
-get_type (void)
-{
- int k;
- token_t token;
- char *name;
-
- token = lex ();
-
- if (token != tok_typename)
- {
- complain (_("invalid %s declaration"), "%type");
- return t;
- }
-
- name = xstrdup (token_buffer);
-
- for (;;)
- {
- token = lex ();
-
- switch (token)
- {
- case tok_semicolon:
- return lex ();
-
- case tok_comma:
- 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:
- return token;
- }
- }
-}
-
-#endif
\f
-/*------------------------------------------------------------------.
-| 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. |
-`------------------------------------------------------------------*/
+/*-------------------------------------------------------------------.
+| 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;
- symbol_list *p1;
+ 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;
+ symbol_list *crule = NULL;
/* Points to the symbol_list preceding crule. */
- symbol_list *crule1;
-
- p1 = NULL;
+ 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);
+ 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;
+ }
- crule1 = p1;
- if (p1)
- p1->next = p;
- else
- grammar = p;
+ 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;
+ p1 = p;
+ crule = p;
- /* mark the rule's lhs as a nonterminal if not already so. */
+ /* 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);
+ 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. */
+ /* 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;
+ for (;;)
+ {
+ t = lex ();
+ if (t == tok_prec)
+ {
+ t = lex ();
+ crule->ruleprec = symval;
+ t = lex ();
+ }
+
+ if (!(t == tok_identifier || t == tok_left_curly))
+ break;
- 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"));
+ /* 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)
+ copy_guard (crule, rulelength);
t = lex ();
- }
-#if 0
- /* these things can appear as alternatives to rules. */
-/* NO, they cannot.
- a) none of the documentation allows them
- b) most of them scan forward until finding a next %
- thus they may swallow lots of intervening rules
-*/
- else if (t == tok_token)
- {
- parse_token_decl (token_sym, nterm_sym);
- t = lex ();
- }
- else if (t == tok_nterm)
- {
- parse_token_decl (nterm_sym, token_sym);
- t = lex ();
- }
- else if (t == tok_type)
- {
- t = get_type ();
- }
- else if (t == tok_union)
- {
- parse_union_decl ();
- t = lex ();
- }
- else if (t == tok_expect)
- {
- parse_expect_decl ();
- t = lex ();
- }
- else if (t == tok_start)
- {
- parse_start_decl ();
+ }
+ 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 ();
- }
-#endif
+ }
+ else
+ {
+ complain (_("invalid input: %s"), quote (token_buffer));
+ t = lex ();
+ }
- else
- {
- complain (_("invalid input: %s"), quote (token_buffer));
- t = lex ();
- }
- }
/* grammar has been read. Do some checking */
projects / bison.git / blobdiff