+/*
+ * This file is part of DisOrder
+ * Copyright (C) 2008 Richard Kettlewell
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+ * USA
+ */
+
+/** @file lib/macros.c
+ * @brief Macro expansion
+ */
+
+#include <config.h>
+#include "types.h"
+
+#include <string.h>
+#include <ctype.h>
+#include <assert.h>
+
+#include "macros.h"
+#include "mem.h"
+#include "vector.h"
+#include "log.h"
+
+VECTOR_TYPE(mx_node_vector, const struct mx_node *, xrealloc);
+
+/** @brief Parse a template
+ * @param filename Input filename (for diagnostics)
+ * @param line Line number (use 1 on initial call)
+ * @param input Start of text to parse
+ * @param end End of text to parse or NULL
+ * @return Pointer to parse tree root node
+ *
+ * Parses the text in [start, end) and returns an (immutable) parse
+ * tree representing it.
+ *
+ * If @p end is NULL then the whole string is parsed.
+ *
+ * Note that the @p filename value stored in the parse tree is @p filename,
+ * i.e. it is not copied.
+ */
+const struct mx_node *mx_parse(const char *filename,
+ int line,
+ const char *input,
+ const char *end) {
+ int braces, expansion_start_line, argument_start_line;
+ const char *argument_start, *argument_end, *p;
+ struct mx_node_vector v[1];
+ struct dynstr d[1];
+ struct mx_node *head = 0, **tailp = &head, *e;
+ int omitted_terminator;
+
+ if(!end)
+ end = input + strlen(input);
+ while(input < end) {
+ if(*input != '@') {
+ expansion_start_line = line;
+ dynstr_init(d);
+ /* Gather up text without any expansions in. */
+ while(input < end && *input != '@') {
+ if(*input == '\n')
+ ++line;
+ dynstr_append(d, *input++);
+ }
+ dynstr_terminate(d);
+ e = xmalloc(sizeof *e);
+ e->next = 0;
+ e->filename = filename;
+ e->line = expansion_start_line;
+ e->type = MX_TEXT;
+ e->text = d->vec;
+ *tailp = e;
+ tailp = &e->next;
+ continue;
+ }
+ mx_node_vector_init(v);
+ braces = 0;
+ p = input;
+ ++input;
+ expansion_start_line = line;
+ omitted_terminator = 0;
+ while(!omitted_terminator && input < end && *input != '@') {
+ /* Skip whitespace */
+ if(isspace((unsigned char)*input)) {
+ if(*input == '\n')
+ ++line;
+ ++input;
+ continue;
+ }
+ if(*input == '{') {
+ /* This is a bracketed argument. We'll walk over it counting
+ * braces to figure out where the end is. */
+ ++input;
+ argument_start = input;
+ argument_start_line = line;
+ while(input < end && (*input != '}' || braces > 0)) {
+ switch(*input++) {
+ case '{': ++braces; break;
+ case '}': --braces; break;
+ case '\n': ++line; break;
+ }
+ }
+ /* If we run out of input without seeing a '}' that's an error */
+ if(input >= end)
+ fatal(0, "%s:%d: unterminated expansion '%.*s'",
+ filename, argument_start_line,
+ (int)(input - argument_start), argument_start);
+ /* Consistency check */
+ assert(*input == '}');
+ /* Record the end of the argument */
+ argument_end = input;
+ /* Step over the '}' */
+ ++input;
+ if(input < end && isspace((unsigned char)*input)) {
+ /* There is at least some whitespace after the '}'. Look
+ * ahead and see what is after all the whitespace. */
+ for(p = input; p < end && isspace((unsigned char)*p); ++p)
+ ;
+ /* Now we are looking after the whitespace. If it's
+ * anything other than '{', including the end of the input,
+ * then we infer that this expansion finished at the '}' we
+ * just saw. (NB that we don't move input forward to p -
+ * the whitespace is NOT part of the expansion.) */
+ if(p == end || *p != '{')
+ omitted_terminator = 1;
+ }
+ } else {
+ /* We are looking at an unbracketed argument. (A common example would
+ * be the expansion or macro name.) This is terminated by an '@'
+ * (indicating the end of the expansion), a ':' (allowing a subsequent
+ * unbracketed argument) or a '{' (allowing a bracketed argument). The
+ * end of the input will also do. */
+ argument_start = input;
+ argument_start_line = line;
+ while(input < end
+ && *input != '@' && *input != '{' && *input != ':') {
+ if(*input == '\n') ++line;
+ ++input;
+ }
+ argument_end = input;
+ /* Trailing whitespace is not significant in unquoted arguments (and
+ * leading whitespace is eliminated by the whitespace skip above). */
+ while(argument_end > argument_start
+ && isspace((unsigned char)argument_end[-1]))
+ --argument_end;
+ /* Step over the ':' if that's what we see */
+ if(input < end && *input == ':')
+ ++input;
+ }
+ /* Now we have an argument in [argument_start, argument_end), and we know
+ * its filename and initial line number. This is sufficient to parse
+ * it. */
+ mx_node_vector_append(v, mx_parse(filename, argument_start_line,
+ argument_start, argument_end));
+ }
+ /* We're at the end of an expansion. We might have hit the end of the
+ * input, we might have hit an '@' or we might have matched the
+ * omitted_terminator criteria. */
+ if(input < end) {
+ if(!omitted_terminator) {
+ assert(*input == '@');
+ ++input;
+ }
+ }
+ /* @@ terminates this file */
+ if(v->nvec == 0)
+ break;
+ /* Currently we require that the first element, the expansion name, is
+ * always plain text. Removing this restriction would raise some
+ * interesting possibilities but for the time being it is considered an
+ * error. */
+ if(v->vec[0]->type != MX_TEXT)
+ fatal(0, "%s:%d: expansion names may not themselves contain expansions",
+ v->vec[0]->filename, v->vec[0]->line);
+ /* Guarantee a NULL terminator (for the case where there's more than one
+ * argument) */
+ mx_node_vector_terminate(v);
+ e = xmalloc(sizeof *e);
+ e->next = 0;
+ e->filename = filename;
+ e->line = expansion_start_line;
+ e->type = MX_EXPANSION;
+ e->name = v->vec[0]->text;
+ e->nargs = v->nvec - 1;
+ e->args = v->nvec > 1 ? &v->vec[1] : 0;
+ *tailp = e;
+ tailp = &e->next;
+ }
+ return head;
+}
+
+/*
+Local Variables:
+c-basic-offset:2
+comment-column:40
+fill-column:79
+indent-tabs-mode:nil
+End:
+*/
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