-/* Bison Action Scanner
+/* Bison code properties structure and scanner.
- Copyright (C) 2006 Free Software Foundation, Inc.
+ Copyright (C) 2006, 2007 Free Software Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
# define SCAN_CODE_H_
# include "location.h"
-# include "symlist.h"
-/* Keeps track of the maximum number of semantic values to the left of
- a handle (those referenced by $0, $-1, etc.) are required by the
- semantic actions of this grammar. */
+struct symbol_list;
+
+/**
+ * Keeps track of the maximum number of semantic values to the left of a handle
+ * (those referenced by $0, $-1, etc.) that are required by the semantic
+ * actions of this grammar.
+ */
extern int max_left_semantic_context;
-void code_scanner_free (void);
+/**
+ * A code passage captured from the grammar file and possibly translated,
+ * and/or properties associated with such a code passage. Don't break
+ * encapsulation by modifying the fields directly. Use the provided interface
+ * functions.
+ */
+typedef struct code_props {
+ /** Set by the init functions. */
+ enum {
+ CODE_PROPS_NONE, CODE_PROPS_PLAIN,
+ CODE_PROPS_SYMBOL_ACTION, CODE_PROPS_RULE_ACTION
+ } kind;
+
+ /** \c NULL iff \c code_props::kind is \c CODE_PROPS_NONE. */
+ char const *code;
+ /** Undefined iff \c code_props::code is \c NULL. */
+ location location;
+
+ /**
+ * \c false iff either:
+ * - \c code_props_translate_code has never previously been invoked for
+ * the \c code_props that would contain the code passage associated
+ * with \c self. (That \c code_props is not the same as this one if this
+ * one is for a RHS \c symbol_list node. Instead, it's the \c code_props
+ * for the LHS symbol of the same rule.)
+ * - \c code_props_translate_code has been invoked for that \c code_props,
+ * but the symbol value associated with this \c code_props was not
+ * referenced in the code passage.
+ */
+ bool is_value_used;
+
+ /** \c NULL iff \c code_props::kind is not \c CODE_PROPS_RULE_ACTION. */
+ struct symbol_list *rule;
+} code_props;
+
+/**
+ * \pre
+ * - <tt>self != NULL</tt>.
+ * \post
+ * - \c self has been overwritten to contain no code.
+ */
+void code_props_none_init (code_props *self);
-/* The action of the rule R contains $$, $1 etc. referring to the values
- of the rule R. */
-char const *translate_rule_action (symbol_list *r);
+/** Equivalent to \c code_props_none_init. */
+#define CODE_PROPS_NONE_INIT \
+ {CODE_PROPS_NONE, NULL, EMPTY_LOCATION_INIT, false, NULL}
-/* The action A refers to $$ and @$ only, referring to a symbol. */
-char const *translate_symbol_action (char const *a, location l);
+/** Initialized by \c CODE_PROPS_NONE_INIT with no further modification. */
+extern code_props const code_props_none;
-/* The action contains no special escapes, just protect M4 special
- symbols. */
-char const *translate_code (char const *a, location l);
+/**
+ * \pre
+ * - <tt>self != NULL</tt>.
+ * - <tt>code != NULL</tt>.
+ * - \c code is an untranslated code passage containing no Bison escapes.
+ * - \c code was extracted from the grammar file at \c code_loc.
+ * \post
+ * - \c self has been overwritten to represent the specified plain code
+ * passage.
+ * - \c self will become invalid if the caller frees \c code before invoking
+ * \c code_props_translate_code on \c self.
+ */
+void code_props_plain_init (code_props *self, char const *code,
+ location code_loc);
+
+/**
+ * \pre
+ * - <tt>self != NULL</tt>.
+ * - <tt>code != NULL</tt>.
+ * - \c code is an untranslated code passage. The only Bison escapes it
+ * might contain are $$ and \@$, referring to a single symbol.
+ * - \c code was extracted from the grammar file at \c code_loc.
+ * \post
+ * - \c self has been overwritten to represent the specified symbol action.
+ * - \c self will become invalid if the caller frees \c code before invoking
+ * \c code_props_translate_code on \c self.
+ */
+void code_props_symbol_action_init (code_props *self, char const *code,
+ location code_loc);
+
+/**
+ * \pre
+ * - <tt>self != NULL</tt>.
+ * - <tt>code != NULL</tt>.
+ * - <tt>rule != NULL</tt>.
+ * - \c code is the untranslated action of the rule for which \c rule is the
+ * LHS node. Thus, \c code possibly contains Bison escapes such as $$, $1,
+ * $2, etc referring to the values of the rule.
+ * - \c code was extracted from the grammar file at \c code_loc.
+ * \post
+ * - \c self has been overwritten to represent the specified rule action.
+ * - \c self does not claim responsibility for the memory of \c rule.
+ * - \c self will become invalid if:
+ * - The caller frees \c code before invoking \c code_props_translate_code
+ * on \c self.
+ * - The caller frees \c rule.
+ */
+void code_props_rule_action_init (code_props *self, char const *code,
+ location code_loc, struct symbol_list *rule);
+
+/**
+ * \pre
+ * - If there's a code passage contained in \c self and it contains Bison
+ * escapes, all grammar declarations have already been parsed as they may
+ * affect warnings and complaints issued here.
+ * \post
+ * - All M4-special symbols and Bison escapes have been translated in
+ * \c self->code.
+ * - <tt>self->code != self->code\@pre</tt> unless
+ * <tt>self->code\@pre = NULL</tt>.
+ */
+void code_props_translate_code (code_props *self);
+
+/**
+ * \pre
+ * - None.
+ * \post
+ * - The dynamic memory allocated by the previous invocation of
+ * \c code_props_translate_code (if any) was freed. The \c code_props
+ * instance for which \c code_props_translate_code was invoked is now
+ * invalid.
+ */
+void code_scanner_last_string_free (void);
+
+/**
+ * \pre
+ * - None.
+ * \post
+ * - All dynamic memory allocated during invocations of
+ * \c code_props_translate_code (if any) has been freed. All \c code_props
+ * instances may now be invalid.
+ */
+void code_scanner_free (void);
#endif /* !SCAN_CODE_H_ */
projects / bison.git / blobdiff