refactored out the grammar handling. handles epsilons better

examples/grammar.h

@@ -0,0 +1,46 @@
+// Generates a system of equations for generating functions from a grammar.
+//
+// (c) 2015 Mikael Vejdemo-Johansson <mikael@johanssons.org>
+//
+
+// Currently does absolutely no elegance, no caching of information, but rather
+// just prints the generating functions to a provided FILE*.
+//
+
+
+// If a desugared parser has user_data set, the generating function systems will try
+// to interpret it as a string:
+//
+// If this string for an h_ch starts with the character 0, then that character
+// will have weight 0 in the generating function.
+//
+// Use the remaining string to set the preferred name of that parser in the
+// generating function.
+//
+
+#ifndef HAMMER_GRAMMAR__H
+#define HAMMER_GRAMMAR__H
+
+#include "../src/backends/contextfree.h"
+#include "../src/backends/lr.h"
+
+
+// Filched from cfgrammar.c this function extracts the name from user_data if it
+// is set; otherwise assigns a name automatically from its position in some
+// ordering of non-terminals.
+const char *nonterminal_name(const HCFGrammar *g, const HCFChoice *nt);
+
+// This function prints out the monomial generated by a single HCFSequence
+// It returns the resulting exponent for t in length and the number of alternatives
+// accumulated in length. The monomial is (mostly) printed out to the provided FILE*,
+// the caller is responsible for adding a scalar and a power of t to the printout.
+void readsequence(FILE *file, uint32_t *count, uint32_t *length,
+		  const HCFGrammar *g, const HCFSequence *seq);
+
+// This function walks through a grammar and generates an equation for each
+// production rule. The results are printed out to the provided FILE*.
+void h_pprint_gfeqns(FILE *file, const HCFGrammar *g);
+
+
+
+#endif