2 * This file is part of DisOrder
3 * Copyright (C) 2008 Richard Kettlewell
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
21 /** @file lib/macros.c
22 * @brief Macro expansion
46 VECTOR_TYPE(mx_node_vector, const struct mx_node *, xrealloc);
48 /** @brief Definition of an expansion */
50 /** @brief Minimum permitted arguments */
53 /** @brief Maximum permitted arguments */
62 * - @ref EXP_TYPE_MASK
66 /** @brief Macro argument names */
69 /** @brief Callback (cast to appropriate type)
71 * Cast to @ref mx_simple_callback or @ref mx_magic_callback as required. */
74 /** @brief Macro definition
76 * Only for @ref EXP_MACRO expansions. */
77 const struct mx_node *definition;
80 /** @brief Expansion takes pre-expanded strings
82 * @p callback is cast to @ref mx_simple_callback. */
83 #define EXP_SIMPLE 0x0000
85 /** @brief Expansion takes parsed templates, not strings
87 * @p callback is cast to @ref mx_magic_callback. The callback must do its own
88 * expansion e.g. via mx_expandstr() where necessary. */
89 #define EXP_MAGIC 0x0001
91 /** @brief Expansion is a macro */
92 #define EXP_MACRO 0x0002
94 /** @brief Mask of types */
95 #define EXP_TYPE_MASK 0x0003
97 /** @brief Hash of all expansions
99 * Created by mx_register(), mx_register_macro() or mx_register_magic().
101 static hash *expansions;
103 static int mx__expand_macro(const struct expansion *e,
104 const struct mx_node *m,
108 /* Parsing ------------------------------------------------------------------ */
110 static int next_non_whitespace(const char *input,
112 while(input < end && isspace((unsigned char)*input))
114 return input < end ? *input : -1;
117 /** @brief Parse a template
118 * @param filename Input filename (for diagnostics)
119 * @param line Line number (use 1 on initial call)
120 * @param input Start of text to parse
121 * @param end End of text to parse or NULL
122 * @return Pointer to parse tree root node
124 * Parses the text in [start, end) and returns an (immutable) parse
125 * tree representing it.
127 * If @p end is NULL then the whole string is parsed.
129 * Note that the @p filename value stored in the parse tree is @p filename,
130 * i.e. it is not copied.
132 const struct mx_node *mx_parse(const char *filename,
136 int braces, argument_start_line, obracket, cbracket;
137 const char *argument_start, *argument_end;
138 struct mx_node_vector v[1];
140 struct mx_node *head = 0, **tailp = &head, *e;
143 end = input + strlen(input);
146 e = xmalloc(sizeof *e);
148 e->filename = filename;
152 /* Gather up text without any expansions in. */
153 while(input < end && *input != '@') {
156 dynstr_append(d, *input++);
167 /* '@@' expands to '@' */
168 e = xmalloc(sizeof *e);
170 e->filename = filename;
179 /* '@#' starts a (newline-eating comment), like dnl */
181 while(input < end && *input != '\n')
189 /* '@_' expands to nothing. It's there to allow dump to terminate
190 * expansions without having to know what follows. */
194 /* It's a full expansion */
196 e = xmalloc(sizeof *e);
198 e->filename = filename;
200 e->type = MX_EXPANSION;
201 /* Collect the expansion name. Expansion names start with an alnum and
202 * consist of alnums and '-'. We don't permit whitespace between the '@'
206 fatal(0, "%s:%d: invalid expansion syntax (truncated)",
208 if(!isalnum((unsigned char)*input))
209 fatal(0, "%s:%d: invalid expansion syntax (unexpected %#x)",
210 filename, e->line, (unsigned char)*input);
211 while(input < end && (isalnum((unsigned char)*input) || *input == '-'))
212 dynstr_append(d, *input++);
215 /* See what the bracket character is */
216 obracket = next_non_whitespace(input, end);
218 case '(': cbracket = ')'; break;
219 case '[': cbracket = ']'; break;
220 case '{': cbracket = '}'; break;
221 default: cbracket = obracket = -1; break; /* no arguments */
223 mx_node_vector_init(v);
225 /* Gather up arguments */
226 while(next_non_whitespace(input, end) == obracket) {
227 while(isspace((unsigned char)*input)) {
232 ++input; /* the bracket */
234 /* Find the end of the argument */
235 argument_start = input;
236 argument_start_line = line;
237 while(input < end && (*input != cbracket || braces > 0)) {
238 const int c = *input++;
242 else if(c == cbracket)
248 /* We ran out of input without encountering a balanced cbracket */
249 fatal(0, "%s:%d: unterminated expansion argument '%.*s'",
250 filename, argument_start_line,
251 (int)(input - argument_start), argument_start);
253 /* Consistency check */
254 assert(*input == cbracket);
255 /* Record the end of the argument */
256 argument_end = input;
257 /* Step over the cbracket */
259 /* Now we have an argument in [argument_start, argument_end), and we
260 * know its filename and initial line number. This is sufficient to
262 mx_node_vector_append(v, mx_parse(filename, argument_start_line,
263 argument_start, argument_end));
266 /* Guarantee a NULL terminator (for the case where there's more than one
268 mx_node_vector_terminate(v);
269 /* Fill in the remains of the node */
278 static void mx__dump(struct dynstr *d, const struct mx_node *m) {
280 const struct mx_node *mm;
286 if(m->text[0] == '@')
287 dynstr_append(d, '@');
288 dynstr_append_string(d, m->text);
291 dynstr_append(d, '@');
292 dynstr_append_string(d, m->name);
293 for(n = 0; n < m->nargs; ++n) {
294 dynstr_append(d, '{');
295 mx__dump(d, m->args[n]);
296 dynstr_append(d, '}');
298 /* If the next non-whitespace is '{', add @_ to stop it being
301 while(mm && mm->type == MX_TEXT) {
302 switch(next_non_whitespace(mm->text, mm->text + strlen(mm->text))) {
307 dynstr_append_string(d, "@_");
316 assert(!"invalid m->type");
318 mx__dump(d, m->next);
321 /** @brief Dump a parse macro expansion to a string
323 * Not of production quality! Only intended for testing!
325 char *mx_dump(const struct mx_node *m) {
334 /* Expansion registration --------------------------------------------------- */
336 static int mx__register(unsigned flags,
342 const struct mx_node *definition) {
343 struct expansion e[1];
346 expansions = hash_new(sizeof(struct expansion));
351 e->callback = callback;
352 e->definition = definition;
353 return hash_add(expansions, name, &e, HASH_INSERT_OR_REPLACE);
356 /** @brief Register a simple expansion rule
358 * @param min Minimum number of arguments
359 * @param max Maximum number of arguments
360 * @param callback Callback to write output
362 void mx_register(const char *name,
365 mx_simple_callback *callback) {
366 mx__register(EXP_SIMPLE, name, min, max, 0, (void (*)())callback, 0);
369 /** @brief Register a magic expansion rule
371 * @param min Minimum number of arguments
372 * @param max Maximum number of arguments
373 * @param callback Callback to write output
375 void mx_register_magic(const char *name,
378 mx_magic_callback *callback) {
379 mx__register(EXP_MAGIC, name, min, max, 0, (void (*)())callback, 0);
382 /** @brief Register a macro
384 * @param nargs Number of arguments
385 * @param args Argument names
386 * @param definition Macro definition
387 * @return 0 on success, negative on error
389 int mx_register_macro(const char *name,
392 const struct mx_node *definition) {
393 if(mx__register(EXP_MACRO, name, nargs, nargs, args, 0/*callback*/,
396 /* This locates the error to the definition, which may be a line or two
397 * beyond the @define command itself. The backtrace generated by
398 * mx_expand() may help more. */
399 error(0, "%s:%d: duplicate definition of '%s'",
400 definition->filename, definition->line, name);
407 /* Expansion ---------------------------------------------------------------- */
409 /** @brief Expand a template
410 * @param m Where to start
411 * @param output Where to send output
413 * @return 0 on success, non-0 on error
415 * Interpretation of return values:
417 * - -1 means an error writing to the sink.
418 * - other negative values mean errors generated from with the macro
420 * - positive values are reserved for the application
422 * If any callback returns non-zero then that value is returned, abandoning
425 int mx_expand(const struct mx_node *m,
428 const struct expansion *e;
435 if(sink_writes(output, m->text) < 0)
440 if(!(e = hash_find(expansions, m->name))) {
441 error(0, "%s:%d: unknown expansion name '%s'",
442 m->filename, m->line, m->name);
443 if(sink_printf(output, "[['%s' unknown]]", m->name) < 0)
445 } else if(m->nargs < e->min) {
446 error(0, "%s:%d: expansion '%s' requires %d args, only %d given",
447 m->filename, m->line, m->name, e->min, m->nargs);
448 if(sink_printf(output, "[['%s' too few args]]", m->name) < 0)
450 } else if(m->nargs > e->max) {
451 error(0, "%s:%d: expansion '%s' takes at most %d args, but %d given",
452 m->filename, m->line, m->name, e->max, m->nargs);
453 if(sink_printf(output, "[['%s' too many args]]", m->name) < 0)
455 } else switch(e->flags & EXP_TYPE_MASK) {
457 /* Magic callbacks we can call directly */
458 rc = ((mx_magic_callback *)e->callback)(m->nargs,
465 /* For simple callbacks we expand their arguments for them. */
466 char **args = xcalloc(1 + m->nargs, sizeof (char *)), *argname;
469 for(n = 0; n < m->nargs; ++n) {
470 /* Argument numbers are at least clear from looking at the text;
471 * adding names as well would be nice. TODO */
472 byte_xasprintf(&argname, "argument #%d", n);
473 if((rc = mx_expandstr(m->args[n], &args[n], u, argname)))
478 rc = ((mx_simple_callback *)e->callback)(m->nargs,
486 /* Macros we expand by rewriting their definition with argument values
487 * substituted and then expanding that. */
488 rc = mx__expand_macro(e, m, output, u);
492 assert(!"impossible EXP_TYPE_MASK value");
495 /* For non-IO errors we generate some backtrace */
497 error(0, " ...in @%s at %s:%d",
498 m->name, m->filename, m->line);
503 assert(!"invalid m->type");
505 return mx_expand(m->next, output, u);
508 /** @brief Expand a template storing the result in a string
509 * @param m Where to start
510 * @param sp Where to store string
512 * @param what Token for backtrace, or NULL
513 * @return 0 on success, non-0 on error
515 * Same return conventions as mx_expand(). This wrapper is slightly more
516 * convenient to use from 'magic' expansions.
518 int mx_expandstr(const struct mx_node *m,
526 if(!(rc = mx_expand(m, sink_dynstr(d), u))) {
531 if(rc && rc != -1 && what)
532 error(0, " ...in %s at %s:%d", what, m->filename, m->line);
536 /** @brief Expand a template file
537 * @param path Filename
538 * @param output Where to send output
540 * @return 0 on success, non-0 on error
542 * Same return conventions as mx_expand().
544 int mx_expand_file(const char *path,
551 const struct mx_node *m;
553 if((fd = open(path, O_RDONLY)) < 0)
554 fatal(errno, "error opening %s", path);
555 if(fstat(fd, &sb) < 0)
556 fatal(errno, "error statting %s", path);
557 if(!S_ISREG(sb.st_mode))
558 fatal(0, "%s: not a regular file", path);
560 b = xmalloc_noptr(sb.st_size);
561 while(sofar < sb.st_size) {
562 n = read(fd, b + sofar, sb.st_size - sofar);
566 fatal(0, "unexpected EOF reading %s", path);
567 else if(errno != EINTR)
568 fatal(errno, "error reading %s", path);
571 m = mx_parse(path, 1, b, b + sb.st_size);
572 rc = mx_expand(m, output, u);
574 /* Mention inclusion in backtrace */
575 error(0, " ...in inclusion of file '%s'", path);
579 /* Macros ------------------------------------------------------------------- */
581 /** @brief Rewrite a parse tree substituting sub-expansions
582 * @param m Parse tree to rewrite (from macro definition)
583 * @param ... Name/value pairs to rewrite
584 * @return Rewritten parse tree
586 * The name/value pair list consists of pairs of strings and is terminated by
587 * (char *)0. Names and values are both copied so need not survive the call.
589 const struct mx_node *mx_rewritel(const struct mx_node *m,
592 hash *h = hash_new(sizeof (struct mx_node *));
597 while((n = va_arg(ap, const char *))) {
598 v = va_arg(ap, const char *);
599 e = xmalloc(sizeof *e);
601 e->filename = m->filename;
604 e->text = xstrdup(v);
605 hash_add(h, n, &e, HASH_INSERT);
606 /* hash_add() copies n */
608 return mx_rewrite(m, h);
611 /** @brief Rewrite a parse tree substituting in macro arguments
612 * @param definition Parse tree to rewrite (from macro definition)
613 * @param h Hash mapping argument names to argument values
614 * @return Rewritten parse tree
616 const struct mx_node *mx_rewrite(const struct mx_node *definition,
618 const struct mx_node *head = 0, **tailp = &head, *argvalue, *m, *mm, **ap;
622 for(m = definition; m; m = m->next) {
625 nm = xmalloc(sizeof *nm);
626 *nm = *m; /* Dumb copy of text node fields */
627 nm->next = 0; /* Maintain list structure */
629 tailp = (const struct mx_node **)&nm->next;
633 && (ap = hash_find(h, m->name))) {
634 /* This expansion has no arguments and its name matches one of the
635 * macro arguments. (Even if it's a valid expansion name we override
636 * it.) We insert its value at this point. We do NOT recursively
637 * rewrite the argument's value - it is outside the lexical scope of
640 * We need to recreate the list structure but a shallow copy will
644 for(mm = argvalue; mm; mm = mm->next) {
645 nm = xmalloc(sizeof *nm);
649 tailp = (const struct mx_node **)&nm->next;
652 /* This is some other expansion. We recursively rewrite its argument
653 * values according to h. */
654 nm = xmalloc(sizeof *nm);
656 nm->args = xcalloc(nm->nargs, sizeof (struct mx_node *));
657 for(n = 0; n < nm->nargs; ++n)
658 nm->args[n] = mx_rewrite(m->args[n], h);
661 tailp = (const struct mx_node **)&nm->next;
665 assert(!"invalid m->type");
668 *tailp = 0; /* Mark end of list */
672 /** @brief Expand a macro
673 * @param e Macro definition
674 * @param m Macro expansion
675 * @param output Where to send output
677 * @return 0 on success, non-0 on error
679 static int mx__expand_macro(const struct expansion *e,
680 const struct mx_node *m,
683 hash *h = hash_new(sizeof (struct mx_node *));
686 /* We store the macro arguments in a hash. Currently there is no check for
687 * duplicate argument names (and this would be the wrong place for it
688 * anyway); if you do that you just lose in some undefined way. */
689 for(n = 0; n < m->nargs; ++n)
690 hash_add(h, e->args[n], &m->args[n], HASH_INSERT);
691 /* Generate a rewritten parse tree */
692 m = mx_rewrite(e->definition, h);
693 /* Expand the result */
694 return mx_expand(m, output, u);
695 /* mx_expand() will update the backtrace */