Create a new internal interface for defining new make functions.

This allows us to create new functions without changing function.c.
You still have to modify the GNU make code (for now) though: this is
simply a preliminary step to possibly allowing make to load modules.

Modify the Guile integration to use this method rather than ifdefs
in function.c.

ChangeLog

@@ -1,5 +1,13 @@
 2012-01-15  Paul Smith  <psmith@gnu.org>
 
+	* variable.h: Prototype an interface for defining new make functions.
+	* function.c (define_new_function): Define it.
+	(func_guile): Remove the "guile" function.
+	(function_table_init): Ditto.
+	* guile.c (func_guile): Add the "guile" function here.
+	(setup_guile): Call define_new_function() to define it.
+	(guile_eval_string): Obsolete.
+
 	* all: Update copyright notices.
 
 2012-01-12  Paul Smith  <psmith@gnu.org>

function.c

@@ -2103,21 +2103,6 @@ func_abspath (char *o, char **argv, const char *funcname UNUSED)
   return o;
 }
 
-#ifdef HAVE_GUILE
-static char *
-func_guile (char *o, char **argv, const char *funcname UNUSED)
-{
-  if (argv[0] && argv[0][0] != '\0')
-    {
-      char *str = guile_eval_string (argv[0]);
-      o = variable_buffer_output (o, str, strlen (str));
-      free (str);
-    }
-
-  return o;
-}
-#endif
-
 /* Lookup table for builtin functions.
 
    This doesn't have to be sorted; we use a straight lookup.  We might gain
@@ -2171,9 +2156,6 @@ static struct function_table_entry function_table_init[] =
   { STRING_SIZE_TUPLE("and"),           1,  0,  0,  func_and},
   { STRING_SIZE_TUPLE("value"),         0,  1,  1,  func_value},
   { STRING_SIZE_TUPLE("eval"),          0,  1,  1,  func_eval},
-#ifdef HAVE_GUILE
-  { STRING_SIZE_TUPLE("guile"),         0,  1,  1,  func_guile},
-#endif
 #ifdef EXPERIMENTAL
   { STRING_SIZE_TUPLE("eq"),            2,  2,  1,  func_eq},
   { STRING_SIZE_TUPLE("not"),           0,  1,  1,  func_not},
@@ -2431,6 +2413,33 @@ func_call (char *o, char **argv, const char *funcname UNUSED)
   return o + strlen (o);
 }
 
+void
+define_new_function(const struct floc *flocp,
+                    const char *name, int min, int max, int expand,
+                    char *(*func)(char *, char **, const char *))
+{
+  size_t len = strlen (name);
+  struct function_table_entry *ent = xmalloc (sizeof (struct function_table_entry));
+
+  if (len > 255)
+    fatal (flocp, _("Function name too long: %s\n"), name);
+  if (min < 0 || min > 255)
+    fatal (flocp, _("Invalid minimum argument count (%d) for function %s%s\n"),
+           min, name);
+  if (max < 0 || max > 255 || max < min)
+    fatal (flocp, _("Invalid maximum argument count (%d) for function %s%s\n"),
+           max, name);
+
+  ent->name = name;
+  ent->len = len;
+  ent->minimum_args = min;
+  ent->maximum_args = max;
+  ent->expand_args = expand ? 1 : 0;
+  ent->func_ptr = func;
+
+  hash_insert (&function_table, ent);
+}
+
 void
 hash_init_function_table (void)
 {

guile.c

@@ -85,20 +85,33 @@ internal_guile_eval (void *arg)
   return cvt_scm_to_str (scm_c_eval_string (arg));
 }
 
-/* ----- Public interface ----- */
+/* This is the function registered with make  */
-
+static char *
-/* This is the make interface for passing programs to Guile.  */
+func_guile (char *o, char **argv, const char *funcname UNUSED)
-char *
-guile_eval_string (char *str)
 {
-  return scm_with_guile (internal_guile_eval, str);
+  if (argv[0] && argv[0][0] != '\0')
+    {
+      char *str = scm_with_guile (internal_guile_eval, argv[0]);
+      o = variable_buffer_output (o, str, strlen (str));
+      free (str);
+    }
+
+  return o;
 }
 
-void
+/* ----- Public interface ----- */
+
+int
 setup_guile ()
 {
+  /* Initialize the Guile interpreter.  */
   scm_with_guile (guile_init, NULL);
 
+  /* Create a make function "guile".  */
+  define_new_function (NILF, "guile", 0, 1, 1, func_guile);
+
   /* Add 'guile' to the list of features. */
   do_variable_definition (NILF, ".FEATURES", "guile", o_default, f_append, 0);
+
+  return 1;
 }

make.h

@@ -466,8 +466,7 @@ const char *strcache_add_len (const char *str, unsigned int len);
 int strcache_setbufsize (unsigned int size);
 
 /* Guile support  */
-char *guile_eval_string (char *str);
+int setup_guile (void);
-void setup_guile (void);
 
 
 #ifdef  HAVE_VFORK_H

variable.h

@@ -167,6 +167,9 @@ struct variable *try_variable_definition (const struct floc *flocp, char *line,
                                           int target_var);
 void init_hash_global_variable_set (void);
 void hash_init_function_table (void);
+void define_new_function(const struct floc *flocp,
+                         const char *name, int min, int max, int expand,
+                         char *(*func)(char *, char **, const char *));
 struct variable *lookup_variable (const char *name, unsigned int length);
 struct variable *lookup_variable_in_set (const char *name, unsigned int length,
                                          const struct variable_set *set);