+ m = mx_parse(path, 1, b, b + sb.st_size);
+ rc = mx_expand(m, output, u);
+ if(rc && rc != -1)
+ /* Mention inclusion in backtrace */
+ error(0, " ...in inclusion of file '%s'", path);
+ return rc;
+}
+
+/* Macros ------------------------------------------------------------------- */
+
+/** @brief Rewrite a parse tree substituting sub-expansions
+ * @param m Parse tree to rewrite (from macro definition)
+ * @param ... Name/value pairs to rewrite
+ * @return Rewritten parse tree
+ *
+ * The name/value pair list consists of pairs of strings and is terminated by
+ * (char *)0. Names and values are both copied so need not survive the call.
+ */
+const struct mx_node *mx_rewritel(const struct mx_node *m,
+ ...) {
+ va_list ap;
+ hash *h = hash_new(sizeof (struct mx_node *));
+ const char *n, *v;
+ struct mx_node *e;
+
+ va_start(ap, m);
+ while((n = va_arg(ap, const char *))) {
+ v = va_arg(ap, const char *);
+ e = xmalloc(sizeof *e);
+ e->next = 0;
+ e->filename = m->filename;
+ e->line = m->line;
+ e->type = MX_TEXT;
+ e->text = xstrdup(v);
+ hash_add(h, n, &e, HASH_INSERT);
+ /* hash_add() copies n */
+ }
+ return mx_rewrite(m, h);
+}
+
+/** @brief Rewrite a parse tree substituting in macro arguments
+ * @param definition Parse tree to rewrite (from macro definition)
+ * @param h Hash mapping argument names to argument values
+ * @return Rewritten parse tree
+ */
+const struct mx_node *mx_rewrite(const struct mx_node *definition,
+ hash *h) {
+ const struct mx_node *head = 0, **tailp = &head, *argvalue, *m, *mm, **ap;
+ struct mx_node *nm;
+ int n;
+
+ for(m = definition; m; m = m->next) {
+ switch(m->type) {
+ case MX_TEXT:
+ nm = xmalloc(sizeof *nm);
+ *nm = *m; /* Dumb copy of text node fields */
+ nm->next = 0; /* Maintain list structure */
+ *tailp = nm;
+ tailp = (const struct mx_node **)&nm->next;
+ break;
+ case MX_EXPANSION:
+ if(m->nargs == 0
+ && (ap = hash_find(h, m->name))) {
+ /* This expansion has no arguments and its name matches one of the
+ * macro arguments. (Even if it's a valid expansion name we override
+ * it.) We insert its value at this point. We do NOT recursively
+ * rewrite the argument's value - it is outside the lexical scope of
+ * the argument name.
+ *
+ * We need to recreate the list structure but a shallow copy will
+ * suffice here.
+ */
+ argvalue = *ap;
+ for(mm = argvalue; mm; mm = mm->next) {
+ nm = xmalloc(sizeof *nm);
+ *nm = *mm;
+ nm->next = 0;
+ *tailp = nm;
+ tailp = (const struct mx_node **)&nm->next;
+ }
+ } else {
+ /* This is some other expansion. We recursively rewrite its argument
+ * values according to h. */
+ nm = xmalloc(sizeof *nm);
+ *nm = *m;
+ nm->args = xcalloc(nm->nargs, sizeof (struct mx_node *));
+ for(n = 0; n < nm->nargs; ++n)
+ nm->args[n] = mx_rewrite(m->args[n], h);
+ nm->next = 0;
+ *tailp = nm;
+ tailp = (const struct mx_node **)&nm->next;
+ }
+ break;
+ default:
+ assert(!"invalid m->type");
+ }
+ }
+ *tailp = 0; /* Mark end of list */
+ return head;
+}
+
+/** @brief Expand a macro
+ * @param e Macro definition
+ * @param m Macro expansion
+ * @param output Where to send output
+ * @param u User data
+ * @return 0 on success, non-0 on error
+ */
+static int mx__expand_macro(const struct expansion *e,
+ const struct mx_node *m,
+ struct sink *output,
+ void *u) {
+ hash *h = hash_new(sizeof (struct mx_node *));
+ int n;
+
+ /* We store the macro arguments in a hash. Currently there is no check for
+ * duplicate argument names (and this would be the wrong place for it
+ * anyway); if you do that you just lose in some undefined way. */
+ for(n = 0; n < m->nargs; ++n)
+ hash_add(h, e->args[n], &m->args[n], HASH_INSERT);
+ /* Generate a rewritten parse tree */
+ m = mx_rewrite(e->definition, h);
+ /* Expand the result */
+ return mx_expand(m, output, u);
+ /* mx_expand() will update the backtrace */