Renamed grammar -> definitions

1 files changed, 93 insertions, 0 deletions

diff --git a/definitions.c b/definitions.c
new file mode 100644
index 0000000..b2c777d
--- /dev/null
+++ b/definitions.c
@@ -0,0 +1,93 @@
+//
+// definitions.c - Code for defining named pattern rules
+//
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "pattern.h"
+#include "files.h"
+#include "definitions.h"
+#include "utils.h"
+
+//
+// Return a new list of definitions with one added to the front
+//
+def_t *with_def(def_t *defs, file_t *f, size_t namelen, const char *name, pat_t *pat)
+{
+    def_t *def = new(def_t);
+    def->next = defs;
+    def->file = f;
+    def->namelen = namelen;
+    def->name = name;
+    def->pat = pat;
+    return def;
+}
+
+//
+// Load the given grammar (semicolon-separated definitions)
+// and return the first rule defined.
+//
+def_t *load_grammar(def_t *defs, file_t *f)
+{
+    const char *src = f->contents;
+    src = after_spaces(src);
+    while (src < f->end) {
+        const char *name = src;
+        src = after_name(name);
+        check(src > name, "Invalid name for definition: %s", name);
+        size_t namelen = (size_t)(src - name);
+        check(matchchar(&src, ':'), "Expected ':' in definition");
+        pat_t *pat = bp_pattern(f, src);
+        if (pat == NULL) break;
+        defs = with_def(defs, f, namelen, name, pat);
+        src = pat->end;
+        src = after_spaces(src);
+        if (matchchar(&src, ';'))
+            src = after_spaces(src);
+    }
+    if (src < f->end) {
+        fprint_line(stderr, f, src, NULL, "Invalid BP pattern");
+        exit(1);
+    }
+    return defs;
+}
+
+//
+// Look up a backreference or grammar definition by name
+//
+def_t *lookup(def_t *defs, const char *name)
+{
+    for ( ; defs; defs = defs->next) {
+        if (strlen(name) == defs->namelen && strncmp(defs->name, name, defs->namelen) == 0)
+            return defs;
+    }
+    return NULL;
+}
+
+//
+// Push a backreference onto the backreference stack
+//
+def_t *with_backref(def_t *defs, file_t *f, const char *name, match_t *m)
+{
+    pat_t *backref = new_pat(f, m->start, VM_BACKREF);
+    backref->end = m->end;
+    backref->len = -1; // TODO: maybe calculate this? (nontrivial because of replacements)
+    backref->args.backref = m;
+    return with_def(defs, f, strlen(name), name, backref);
+}
+
+//
+// Free all the given definitions up till (but not including) `stop`
+//
+void free_defs(def_t **defs, def_t *stop)
+{
+    while (*defs != stop && *defs != NULL) {
+        def_t *next = (*defs)->next;
+        (*defs)->next = NULL;
+        free(*defs);
+        (*defs) = next;
+    }
+}
+
+// vim: ts=4 sw=0 et cino=L2,l1,(0,W4,m1