grammar: warn about unused precedence for symbols

[bison.git] / src / symtab.h

diff --git a/src/symtab.h b/src/symtab.h
index 1a50bb95b793c4a1073bdc93f8d60f0e6dfe68b3..fee549999e3f0e34974b8a742bc5e5d05eff01f5 100644 (file)
--- a/src/symtab.h
+++ b/src/symtab.h
@@ -224,6 +224,52 @@ extern symbol *startsymbol;
 extern location startsymbol_location;
 
 
 extern location startsymbol_location;
 
 

+
+/*-------------------.
+| Symbol Relations.  |
+`-------------------*/
+
+/* The symbol relations are represented by a directed graph. */
+
+/* The id of a node */
+typedef int graphid;
+
+typedef struct symgraphlink symgraphlink;
+
+struct symgraphlink
+{
+  /** The second \c symbol or group of a precedence relation.
+   * See \c symgraph. */
+  graphid id;
+
+  symgraphlink *next;
+};
+
+/* Symbol precedence graph, to store the used precedence relations between
+ * symbols. */
+
+typedef struct symgraph symgraph;
+
+struct symgraph
+{
+  /** Identifier for the node: equal to the number of the symbol. */
+  graphid id;
+
+  /** The list of related symbols that have a smaller precedence. */
+  symgraphlink *succ;
+
+  /** The list of related symbols that have a greater precedence. */
+  symgraphlink *pred;
+};
+
+/** Register a new precedence relation as used. */
+
+void register_precedence (graphid first, graphid snd);
+
+/** Print a warning for each symbol whose precedence is useless. */
+
+void print_precedence_warnings (void);
+

 /*-----------------.
 | Semantic types.  |
 `-----------------*/
 /*-----------------.
 | Semantic types.  |
 `-----------------*/