+static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
+{
+ int err = regcomp(&p->regexp, p->pattern, opt->regflags);
+ if (err) {
+ char errbuf[1024];
+ char where[1024];
+ if (p->no)
+ sprintf(where, "In '%s' at %d, ",
+ p->origin, p->no);
+ else if (p->origin)
+ sprintf(where, "%s, ", p->origin);
+ else
+ where[0] = 0;
+ regerror(err, &p->regexp, errbuf, 1024);
+ regfree(&p->regexp);
+ die("%s'%s': %s", where, p->pattern, errbuf);
+ }
+}
+
+#if DEBUG
+static inline void indent(int in)
+{
+ int i;
+ for (i = 0; i < in; i++) putchar(' ');
+}
+
+static void dump_pattern_exp(struct grep_expr *x, int in)
+{
+ switch (x->node) {
+ case GREP_NODE_ATOM:
+ indent(in);
+ puts(x->u.atom->pattern);
+ break;
+ case GREP_NODE_NOT:
+ indent(in);
+ puts("--not");
+ dump_pattern_exp(x->u.unary, in+1);
+ break;
+ case GREP_NODE_AND:
+ dump_pattern_exp(x->u.binary.left, in+1);
+ indent(in);
+ puts("--and");
+ dump_pattern_exp(x->u.binary.right, in+1);
+ break;
+ case GREP_NODE_OR:
+ dump_pattern_exp(x->u.binary.left, in+1);
+ indent(in);
+ puts("--or");
+ dump_pattern_exp(x->u.binary.right, in+1);
+ break;
+ }
+}
+
+static void looking_at(const char *msg, struct grep_pat **list)
+{
+ struct grep_pat *p = *list;
+ fprintf(stderr, "%s: looking at ", msg);
+ if (!p)
+ fprintf(stderr, "empty\n");
+ else
+ fprintf(stderr, "<%s>\n", p->pattern);
+}
+#else
+#define looking_at(a,b) do {} while(0)
+#endif
+
+static struct grep_expr *compile_pattern_expr(struct grep_pat **);
+static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
+{
+ struct grep_pat *p;
+ struct grep_expr *x;
+
+ looking_at("atom", list);
+
+ p = *list;
+ switch (p->token) {
+ case GREP_PATTERN: /* atom */
+ x = xcalloc(1, sizeof (struct grep_expr));
+ x->node = GREP_NODE_ATOM;
+ x->u.atom = p;
+ *list = p->next;
+ return x;
+ case GREP_OPEN_PAREN:
+ *list = p->next;
+ x = compile_pattern_expr(list);
+ if (!x)
+ return NULL;
+ if (!*list || (*list)->token != GREP_CLOSE_PAREN)
+ die("unmatched parenthesis");
+ *list = (*list)->next;
+ return x;
+ default:
+ return NULL;
+ }
+}
+
+static struct grep_expr *compile_pattern_not(struct grep_pat **list)
+{
+ struct grep_pat *p;
+ struct grep_expr *x;
+
+ looking_at("not", list);
+
+ p = *list;
+ switch (p->token) {
+ case GREP_NOT:
+ if (!p->next)
+ die("--not not followed by pattern expression");
+ *list = p->next;
+ x = xcalloc(1, sizeof (struct grep_expr));
+ x->node = GREP_NODE_NOT;
+ x->u.unary = compile_pattern_not(list);
+ if (!x->u.unary)
+ die("--not followed by non pattern expression");
+ return x;
+ default:
+ return compile_pattern_atom(list);
+ }
+}
+
+static struct grep_expr *compile_pattern_and(struct grep_pat **list)
+{
+ struct grep_pat *p;
+ struct grep_expr *x, *y, *z;
+
+ looking_at("and", list);
+
+ x = compile_pattern_not(list);
+ p = *list;
+ if (p && p->token == GREP_AND) {
+ if (!p->next)
+ die("--and not followed by pattern expression");
+ *list = p->next;
+ y = compile_pattern_and(list);
+ if (!y)
+ die("--and not followed by pattern expression");
+ z = xcalloc(1, sizeof (struct grep_expr));
+ z->node = GREP_NODE_AND;
+ z->u.binary.left = x;
+ z->u.binary.right = y;
+ return z;
+ }
+ return x;
+}
+
+static struct grep_expr *compile_pattern_or(struct grep_pat **list)
+{
+ struct grep_pat *p;
+ struct grep_expr *x, *y, *z;
+
+ looking_at("or", list);
+
+ x = compile_pattern_and(list);
+ p = *list;
+ if (x && p && p->token != GREP_CLOSE_PAREN) {
+ y = compile_pattern_or(list);
+ if (!y)
+ die("not a pattern expression %s", p->pattern);
+ z = xcalloc(1, sizeof (struct grep_expr));
+ z->node = GREP_NODE_OR;
+ z->u.binary.left = x;
+ z->u.binary.right = y;
+ return z;
+ }
+ return x;
+}
+
+static struct grep_expr *compile_pattern_expr(struct grep_pat **list)
+{
+ looking_at("expr", list);
+
+ return compile_pattern_or(list);
+}
+