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-rw-r--r--Makefile13
-rw-r--r--bpeg.c780
2 files changed, 793 insertions, 0 deletions
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..eae2d13
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,13 @@
+PREFIX=
+CFLAGS=-Wall -Wextra -pedantic -Wmissing-prototypes -Wstrict-prototypes
+OFLAGS=-O3
+
+all: bpeg
+
+clean:
+ rm -f bpeg
+
+bpeg: bpeg.c
+ cc $(CFLAGS) $(OFLAGS) $< -o $@
+
+.PHONY: all clean
diff --git a/bpeg.c b/bpeg.c
new file mode 100644
index 0000000..0a4c551
--- /dev/null
+++ b/bpeg.c
@@ -0,0 +1,780 @@
+// # <comment> comment
+// ` <c> character <c>
+// ! <pat> no <pat>
+// ^ <pat> upto <pat>
+// & <pat> upto and including <pat>
+// <N=1> + <pat> [% <sep="">] <N> or more <pat>s (separated by <sep>)
+// * <pat> [% <sep="">] sugar for "0+ <pat> [% <sep>]"
+// <N=1> - <pat> [% <sep="">] <N> or fewer <pat>s (separated by <sep>)
+// ? <pat> sugar for "1- <pat>"
+// <N> - <M> <pat> <N> to <M> (inclusive) <pat>s
+// < <pat> after <pat>, ...
+// > <pat> before <pat>, ...
+// . any character
+// <pat> / <alt> <pat> otherwise <alt>
+// ( <pat> ) <pat>
+// @ <pat> capture <pat>
+// @ [ <name> ] <pat> <pat> named <name>
+// ; <name> = <pat> <name> is defined to be <pat>
+// { <pat> ~ <str> } <pat> replaced with <str>
+// "@1" or "@{1}" first capture
+// "@foo" or "@{foo}" capture named "foo"
+
+#include <ctype.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#define check(cond, ...) do { if (!(cond)) { fprintf(stderr, __VA_ARGS__); _exit(1); } } while(0)
+
+typedef struct match_s {
+ const char *start, *end;
+ union {
+ unsigned int is_capture:1;
+ const char *name;
+ } capture;
+ const char *replacement;
+ struct match_s *child, *nextsibling;
+} match_t;
+
+enum VM_OPTYPE {
+ VM_EMPTY = 0,
+ VM_ANYCHAR = 1,
+ VM_STRING,
+ VM_RANGE,
+ VM_NOT,
+ VM_UPTO,
+ VM_UPTO_AND,
+ VM_REPEAT,
+ VM_BEFORE,
+ VM_AFTER,
+ VM_CAPTURE,
+ VM_OTHERWISE,
+ VM_CHAIN,
+ VM_REPLACE,
+ VM_REF,
+};
+
+typedef struct vm_op_s {
+ enum VM_OPTYPE op;
+ const char *start, *end;
+ ssize_t len;
+ union {
+ const char *s;
+ struct {
+ char low, high;
+ } range;
+ struct {
+ ssize_t min, max;
+ struct vm_op_s *sep, *repeat_pat;
+ } repetitions;
+ struct {
+ struct vm_op_s *first, *second;
+ } multiple;
+ struct {
+ struct vm_op_s *replace_pat;
+ const char *replacement;
+ } replace;
+ struct {
+ struct vm_op_s *capture_pat;
+ char *name;
+ } capture;
+ struct vm_op_s *pat;
+ } args;
+} vm_op_t;
+
+static match_t *free_match(match_t *m);
+static match_t *match(const char *str, vm_op_t *op);
+static void set_range(vm_op_t *op, ssize_t min, ssize_t max, vm_op_t *pat, vm_op_t *sep);
+static inline const char *skip_spaces(const char *str);
+static vm_op_t *expand_choices(vm_op_t *op);
+static vm_op_t *expand_chain(vm_op_t *first);
+static vm_op_t *parse(const char *str);
+
+
+typedef struct {
+ const char *name;
+ vm_op_t *op;
+} def_t;
+
+static def_t defs[1024] = {{NULL, NULL}};
+size_t ndefs = 0;
+static int verbose = 1;
+
+#define debug(...) do { if (verbose) fprintf(stderr, __VA_ARGS__); } while(0)
+
+
+static match_t *free_match(match_t *m)
+{
+ if (m->child) m->child = free_match(m->child);
+ if (m->nextsibling) m->nextsibling = free_match(m->nextsibling);
+ free(m);
+ return NULL;
+}
+
+static match_t *match(const char *str, vm_op_t *op)
+{
+ tailcall:
+ switch (op->op) {
+ case VM_EMPTY: {
+ match_t *m = calloc(sizeof(match_t), 1);
+ m->start = str;
+ m->end = str;
+ return m;
+ }
+ case VM_ANYCHAR: {
+ if (!*str) return NULL;
+ match_t *m = calloc(sizeof(match_t), 1);
+ m->start = str;
+ m->end = str+1;
+ return m;
+ }
+ case VM_STRING: {
+ if (strncmp(str, op->args.s, op->len) != 0)
+ return NULL;
+ match_t *m = calloc(sizeof(match_t), 1);
+ m->start = str;
+ m->end = str + op->len;
+ return m;
+ }
+ case VM_RANGE: {
+ if (*str < op->args.range.low || *str > op->args.range.high)
+ return NULL;
+ match_t *m = calloc(sizeof(match_t), 1);
+ m->start = str;
+ m->end = str + 1;
+ return m;
+ }
+ case VM_NOT: {
+ match_t *m = match(str, op->args.pat);
+ if (m != NULL) {
+ m = free_match(m);
+ return NULL;
+ }
+ m = calloc(sizeof(match_t), 1);
+ m->start = str;
+ m->end = str;
+ return m;
+ }
+ case VM_UPTO: case VM_UPTO_AND: {
+ match_t *m = calloc(sizeof(match_t), 1);
+ m->start = str;
+ for (; *str; ++str) {
+ match_t *p = match(str, op->args.pat);
+ if (p != NULL) {
+ if (op->op == VM_UPTO) {
+ p = free_match(p);
+ m->end = str;
+ return m;
+ } else {
+ m->end = p->end;
+ m->child = p;
+ return m;
+ }
+ }
+ }
+ m = free_match(m);
+ return NULL;
+ }
+ case VM_REPEAT: {
+ match_t *m = calloc(sizeof(match_t), 1);
+ m->start = str;
+ m->end = str;
+ if (op->args.repetitions.max == 0) return m;
+
+ match_t **dest = &m->child;
+
+ size_t reps = 0;
+ *dest = match(str, op->args.repetitions.repeat_pat);
+ if (*dest != NULL) {
+ ++reps;
+ str = (*dest)->end;
+ dest = &(*dest)->nextsibling;
+
+ if (op->args.repetitions.sep != NULL) {
+ for (; reps < (size_t)op->args.repetitions.max; reps++) {
+ match_t *sep = match(str, op->args.repetitions.sep);
+ if (sep == NULL) break;
+ str = sep->end;
+ match_t *p = match(str, op->args.repetitions.repeat_pat);
+ if (p == NULL) {
+ p = free_match(p);
+ break;
+ }
+ str = p->end;
+ *dest = sep;
+ sep->nextsibling = p;
+ dest = &p->nextsibling;
+ }
+ } else {
+ for (; reps < (size_t)op->args.repetitions.max; reps++) {
+ *dest = match(str, op->args.repetitions.repeat_pat);
+ if (*dest == NULL) break;
+ str = (*dest)->end;
+ dest = &(*dest)->nextsibling;
+ }
+ }
+ }
+ if ((ssize_t)reps < op->args.repetitions.min) {
+ m = free_match(m);
+ return NULL;
+ }
+ m->end = str;
+ return m;
+ }
+ case VM_AFTER: {
+ check(op->len != -1, "'<' is only allowed for fixed-length operations");
+ // Check for necessary space:
+ for (int i = 0; i < op->len; i++) {
+ if (str[-i] == '\0') return NULL;
+ }
+ match_t *before = match(str-op->len, op->args.pat);
+ if (before == NULL) return NULL;
+ before = free_match(before);
+ match_t *m = calloc(sizeof(match_t), 1);
+ m->start = str;
+ m->end = str;
+ return m;
+ }
+ case VM_BEFORE: {
+ match_t *after = match(str, op->args.pat);
+ if (after == NULL) return NULL;
+ after = free_match(after);
+ match_t *m = calloc(sizeof(match_t), 1);
+ m->start = str;
+ m->end = str;
+ return m;
+ }
+ case VM_CAPTURE: {
+ match_t *p = match(str, op->args.pat);
+ if (p == NULL) return NULL;
+ match_t *m = calloc(sizeof(match_t), 1);
+ m->start = str;
+ m->end = p->end;
+ if (op->args.capture.name)
+ m->capture.name = op->args.capture.name;
+ else
+ m->capture.is_capture = 1;
+ return m;
+ }
+ case VM_OTHERWISE: {
+ match_t *m = match(str, op->args.multiple.first);
+ if (m == NULL) m = match(str, op->args.multiple.second);
+ return m;
+ }
+ case VM_CHAIN: {
+ match_t *m1 = match(str, op->args.multiple.first);
+ if (m1 == NULL) return NULL;
+ match_t *m2 = match(m1->end, op->args.multiple.second);
+ if (m2 == NULL) {
+ m1 = free_match(m1);
+ return NULL;
+ }
+ match_t *m = calloc(sizeof(match_t), 1);
+ m->start = str;
+ m->end = m2->end;
+ m->child = m1;
+ m1->nextsibling = m2;
+ return m;
+ }
+ case VM_REPLACE: {
+ match_t *m = calloc(sizeof(match_t), 1);
+ m->start = str;
+ if (op->args.replace.replace_pat) {
+ match_t *p = match(str, op->args.replace.replace_pat);
+ if (p == NULL) return NULL;
+ m->end = p->end;
+ } else {
+ m->end = m->start;
+ }
+ // TODO: handle captures
+ m->replacement = op->args.replace.replacement;
+ return m;
+ }
+ case VM_REF: {
+ for (size_t i = 0; i < ndefs; i++) {
+ if (strcmp(defs[i].name, op->args.s) == 0) {
+ // Bingo!
+ op = defs[i].op;
+ goto tailcall;
+ }
+ }
+ check(0, "Unknown identifier: '%s'", op->args.s);
+ return NULL;
+ }
+ default: {
+ fprintf(stderr, "Unknown opcode: %d", op->op);
+ _exit(1);
+ return NULL;
+ }
+ }
+}
+
+static void set_range(vm_op_t *op, ssize_t min, ssize_t max, vm_op_t *pat, vm_op_t *sep)
+{
+ op->op = VM_REPEAT;
+ if (pat->len >= 0 && (sep == NULL || sep->len >= 0) && min == max && min >= 0)
+ op->len = pat->len * min + (sep == NULL || min == 0 ? 0 : sep->len * (min-1));
+ else
+ op->len = -1;
+ op->args.repetitions.min = min;
+ op->args.repetitions.max = max;
+ op->args.repetitions.repeat_pat = pat;
+ op->args.repetitions.sep = sep;
+}
+
+static inline const char *skip_spaces(const char *str)
+{
+ // Skip whitespace and comments:
+ skip_whitespace:
+ switch (*str) {
+ case ' ': case '\r': case '\n': case '\t': {
+ ++str;
+ goto skip_whitespace;
+ }
+ case '#': {
+ while (*str && *str != '\n') ++str;
+ goto skip_whitespace;
+ }
+ }
+ return str;
+}
+
+static vm_op_t *expand_chain(vm_op_t *first)
+{
+ vm_op_t *second = parse(first->end);
+ if (second == NULL) return first;
+ check(second->end > first->end, "No forward progress in chain!");
+ second = expand_chain(second);
+ vm_op_t *chain = calloc(sizeof(vm_op_t), 1);
+ chain->op = VM_CHAIN;
+ chain->start = first->start;
+ if (first->len >= 0 && second->len >= 0)
+ chain->len = first->len + second->len;
+ else chain->len = -1;
+ chain->end = second->end;
+ chain->args.multiple.first = first;
+ chain->args.multiple.second = second;
+ return chain;
+}
+
+static vm_op_t *expand_choices(vm_op_t *first)
+{
+ first = expand_chain(first);
+ const char *str = skip_spaces(first->end);
+ if (*str != '/') return first;
+ ++str;
+ vm_op_t *second = parse(str);
+ check(second, "Expected pattern after '/'");
+ second = expand_chain(second);
+ vm_op_t *choice = calloc(sizeof(vm_op_t), 1);
+ choice->op = VM_OTHERWISE;
+ choice->start = first->start;
+ if (first->len == second->len)
+ choice->len = first->len;
+ else choice->len = -1;
+ choice->end = second->end;
+ choice->args.multiple.first = first;
+ choice->args.multiple.second = second;
+ return expand_choices(choice);
+}
+
+static vm_op_t *parse(const char *str)
+{
+ if (!*str) return NULL;
+ debug("Parsing \"%s\"...\n", str);
+ str = skip_spaces(str);
+ check(*str, "Expected a pattern");
+ vm_op_t *op = calloc(sizeof(vm_op_t), 1);
+ op->start = str;
+ op->len = -1;
+ switch (*str) {
+ // Any char (dot)
+ case '.': {
+ ++str;
+ debug("Dot\n");
+ op->op = VM_ANYCHAR;
+ op->len = 1;
+ break;
+ }
+ // Char literals
+ case '`': {
+ ++str;
+ char c[2] = {*str, '\0'};
+ ++str;
+ check(c[0], "Expected character after '`'\n");
+ op->len = 1;
+ if (*str == ',') { // Range
+ debug("Char range\n");
+ char c2 = *(++str);
+ check(c2, "Expected character after ','");
+ op->op = VM_RANGE;
+ op->args.range.low = c[0];
+ op->args.range.high = c2;
+ } else {
+ debug("Char literal\n");
+ op->op = VM_STRING;
+ op->args.s = strdup(c);
+ }
+ break;
+ }
+ // Escapes
+ case '\\': {
+ ++str;
+ debug("Escape sequence\n");
+ check(*str, "Expected escape after '\\'");
+ op->op = VM_STRING;
+ op->len = 1;
+ char c[2] = {*str, '\0'};
+ switch (c[0]) {
+ case 'a': c[0] = '\a'; break;
+ case 'b': c[0] = '\b'; break;
+ case 'n': c[0] = '\n'; break;
+ case 'r': c[0] = '\r'; break;
+ case 't': c[0] = '\t'; break;
+ case 'v': c[0] = '\v'; break;
+ case 'x': { // Hex
+ static const char hextable[255] = {
+ ['0']=0x10, ['1']=0x1, ['2']=0x2, ['3']=0x3, ['4']=0x4,
+ ['5']=0x5, ['6']=0x6, ['7']=0x7, ['8']=0x8, ['9']=0x9,
+ ['a']=0xa, ['b']=0xb, ['c']=0xc, ['d']=0xd, ['e']=0xe, ['f']=0xf,
+ ['A']=0xa, ['B']=0xb, ['C']=0xc, ['D']=0xd, ['E']=0xe, ['F']=0xf,
+ };
+ if (hextable[(int)str[1]] && hextable[(int)str[2]])
+ c[0] = (hextable[(int)str[1]] << 4) | (hextable[(int)str[2]] & 0xF);
+ break;
+ }
+ case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': { // Octal
+ c[0] = c[0] - '0';
+ ++str;
+ if ('0' <= *str && *str <= '7') {
+ c[0] = (c[0] << 3) | (*str - '0');
+ ++str;
+ }
+ if ('0' <= *str && *str <= '7') {
+ c[0] = (c[0] << 3) | (*str - '0');
+ ++str;
+ }
+ break;
+ }
+ default: {
+ check(0, "Invalid escape sequence");
+ }
+ }
+ op->args.s = strdup(c);
+ break;
+ }
+ // String literal
+ case '"': case '\'': {
+ char quote = *str;
+ ++str;
+ const char *literal = str;
+ for (; *str && *str != quote; str++) {
+ if (*str == '\\') {
+ // TODO: handle escape chars like \n
+ check(str[1], "Expected more string contents after backslash");
+ ++str;
+ }
+ }
+ op->op = VM_STRING;
+ op->len = (ssize_t)(str - literal);
+ op->args.s = strndup(literal, (size_t)op->len);
+ debug("String literal: %c%s%c\n", quote, op->args.s, quote);
+ check(*str == quote, "Missing closing quote");
+ ++str;
+ break;
+ }
+ // Not <pat>
+ case '!': {
+ ++str;
+ debug("Not pattern\n");
+ vm_op_t *p = parse(str);
+ check(p, "Expected pattern after '!'\n");
+ str = p->end;
+ op->op = VM_NOT;
+ op->len = 0;
+ op->args.pat = p;
+ break;
+ }
+ // Upto <pat>
+ case '^': {
+ ++str;
+ debug("Upto pattern\n");
+ vm_op_t *p = parse(str);
+ check(p, "Expected pattern after '^'\n");
+ str = p->end;
+ op->op = VM_UPTO;
+ op->len = -1;
+ op->args.pat = p;
+ break;
+ }
+ // Upto and including <pat>
+ case '&': {
+ ++str;
+ debug("Upto-and pattern\n");
+ vm_op_t *p = parse(str);
+ check(p, "Expected pattern after '&'\n");
+ str = p->end;
+ op->op = VM_UPTO_AND;
+ op->len = -1;
+ op->args.pat = p;
+ break;
+ }
+ // Number of repetitions: <N>(-<N> / - / + / "")
+ case '0': case '1': case '2': case '3': case '4': case '5':
+ case '6': case '7': case '8': case '9': {
+ debug("Repetitions\n");
+ ssize_t min = -1, max = -1;
+ long n1 = strtol(str, (char**)&str, 10);
+ str = skip_spaces(str);
+ switch (*str) {
+ case '-': {
+ ++str;
+ str = skip_spaces(str);
+ const char *start = str;
+ long n2 = strtol(str, (char**)&str, 10);
+ if (str == start) min = 0, max = n1;
+ else min = n1, max = n2;
+ break;
+ }
+ case '+': {
+ ++str;
+ min = n1, max = -1;
+ break;
+ }
+ default: {
+ min = n1, max = n1;
+ break;
+ }
+ }
+ vm_op_t *pat = parse(str);
+ check(pat, "Expected pattern after repetition count");
+ str = pat->end;
+ str = skip_spaces(str);
+ if (*str == '%') {
+ ++str;
+ vm_op_t *sep = parse(str);
+ check(sep, "Expected pattern for separator after '%%'");
+ str = sep->end;
+ set_range(op, min, max, pat, sep);
+ } else {
+ set_range(op, min, max, pat, NULL);
+ }
+ debug("min = %lld max = %lld\n", (long long)op->args.repetitions.min, (long long)op->args.repetitions.max);
+ break;
+ }
+ // Special repetitions:
+ case '+': case '*': case '?': {
+ debug("Special repetitions\n");
+ ssize_t min = -1, max = -1;
+ switch (*str) {
+ case '+': min = 1, max = -1; break;
+ case '*': min = 0, max = -1; break;
+ case '?': min = 0, max = 1; break;
+ }
+ ++str;
+ vm_op_t *pat = parse(str);
+ check(pat, "Expected pattern after +");
+ str = pat->end;
+ str = skip_spaces(str);
+ if (*str == '%') {
+ ++str;
+ vm_op_t *sep = parse(str);
+ check(sep, "Expected pattern for separator after '%%'");
+ str = sep->end;
+ set_range(op, min, max, pat, sep);
+ } else {
+ set_range(op, min, max, pat, NULL);
+ }
+ debug("min = %lld max = %lld\n", (long long)op->args.repetitions.min, (long long)op->args.repetitions.max);
+ break;
+ }
+ // Lookbehind
+ case '<': {
+ ++str;
+ debug("Lookbehind\n");
+ vm_op_t *pat = parse(str);
+ check(pat, "Expected pattern after <");
+ str = pat->end;
+ check(pat->len != -1, "Lookbehind patterns must have a fixed length");
+ str = pat->end;
+ op->op = VM_AFTER;
+ op->len = 0;
+ op->args.pat = pat;
+ break;
+ }
+ // Lookahead
+ case '>': {
+ ++str;
+ debug("Lookahead\n");
+ vm_op_t *pat = parse(str);
+ check(pat, "Expected pattern after >");
+ str = pat->end;
+ op->op = VM_BEFORE;
+ op->len = 0;
+ op->args.pat = pat;
+ break;
+ }
+ // Parentheses
+ case '(': {
+ debug("Open paren (\n");
+ ++str;
+ free(op);
+ op = parse(str);
+ check(op, "Expected pattern inside parentheses");
+ op = expand_choices(op);
+ str = op->end;
+ str = skip_spaces(str);
+ check(*str == ')', "Expected closing parenthesis");
+ ++str;
+ debug("Close paren (\n");
+ break;
+ }
+ // Capture
+ case '@': {
+ debug("Capture\n");
+ ++str;
+ op->op = VM_CAPTURE;
+ str = skip_spaces(str);
+ if (*str == '[') {
+ ++str;
+ char *closing = strchr(str, ']');
+ check(closing, "Expected closing ']'");
+ op->args.capture.name = strndup(str, (size_t)(closing-str));
+ debug("named \"%s\"\n", op->args.capture.name);
+ str = closing;
+ ++str;
+ }
+ vm_op_t *pat = parse(str);
+ check(pat, "Expected pattern after @");
+ str = pat->end;
+ op->args.capture.capture_pat = pat;
+ op->len = pat->len;
+ break;
+ }
+ // Replacement
+ case '{': {
+ debug("Replacement {\n");
+ ++str;
+ str = skip_spaces(str);
+ vm_op_t *pat = NULL;
+ if (*str != '~') {
+ pat = parse(str);
+ check(pat, "Expected pattern after '{'");
+ pat = expand_choices(pat);
+ str = pat->end;
+ str = skip_spaces(str+1);
+ }
+ str = skip_spaces(str+1);
+ char quote = *(str++);
+ check(quote == '\'' || quote == '"',
+ "Expected string literal for replacement");
+ const char *replacement = str;
+ for (; *str && *str != quote; str++) {
+ if (*str == '\\') {
+ check(str[1], "Expected more string contents after backslash");
+ ++str;
+ }
+ }
+ replacement = strndup(replacement, (size_t)(str-replacement));
+ ++str;
+ str = skip_spaces(str);
+ check(*str == '}', "Expected a closing '}'");
+ ++str;
+ op->op = VM_REPLACE;
+ op->args.replace.replace_pat = pat;
+ op->args.replace.replacement = replacement;
+ debug(" rep = \"%s\"", replacement);
+ debug("}");
+ if (pat != NULL) op->len = pat->len;
+ break;
+ }
+ // Whitespace
+ case '_': {
+ debug("Whitespace\n");
+ ++str;
+ op->op = VM_REF;
+ op->args.s = strdup("_");
+ break;
+ }
+ default: {
+ // Reference
+ if (isalpha(*str)) {
+ const char *refname = str;
+ size_t len = 1;
+ for (++str; isalnum(*str); ++str)
+ ++len;
+ op->op = VM_REF;
+ debug("Ref: %s\n", refname);
+ op->args.s = strndup(refname, len);
+ break;
+ } else {
+ free(op);
+ return NULL;
+ }
+ }
+ }
+ op->end = str;
+ return op;
+}
+
+static void load_def(const char *name, const char *def)
+{
+ defs[ndefs].name = name;
+ defs[ndefs].op = parse(def);
+ ++ndefs;
+}
+
+static void load_defs(void)
+{
+ load_def("_", "` /\\t/\\n/\\r");
+ load_def("nl", "\\n");
+ load_def("crlf", "\\r\\n");
+ load_def("abc", "`a,z");
+ load_def("ABC", "`A,Z");
+ load_def("Abc", "`a,z/`A,Z");
+ load_def("digit", "`0,9");
+ load_def("number", "+`0,9 ?(`. *`0,9) / `. +`0,9");
+ load_def("hex", "`0,9/`a,f");
+ load_def("Hex", "`0,9/`a,f/`A,F");
+ load_def("HEX", "`0,9/`A,F");
+ load_def("id", "(`a,z/`A,Z/`_) *(`a,z/`A,Z/`_/`0,9)");
+ load_def("line", "&(?\\r\\n / !.)");
+ load_def("parens", "`( *(parens / .) `)");
+ load_def("braces", "`{ *(parens / .) `}");
+ load_def("brackets", "`[ *(parens / .) `]");
+ load_def("anglebraces", "`< *(parens / .) `>");
+}
+
+int main(int argc, char *argv[])
+{
+ load_defs();
+
+ char *lang = argc > 1 ? argv[1] : "'x''y'";
+ vm_op_t *op = parse(lang);
+ check(op, "Failed to parse input");
+ op = expand_choices(op);
+
+ // TODO: check for semicolon and more rules
+
+
+ char *str = argc > 2 ? argv[2] : "xyz";
+
+ // Ensure string has a null byte to the left:
+ char *lpadded = calloc(sizeof(char), strlen(str)+2);
+ stpcpy(&lpadded[1], str);
+ str = &lpadded[1];
+
+ match_t *m = match(str, op);
+ if (m == NULL) {
+ printf("No match\n");
+ } else {
+ printf("%.*s\033[7m%.*s\033[0m%s\n",
+ (int)(str - m->start), str,
+ (int)(m->end - m->start), m->start,
+ m->end);
+ }
+
+ return 0;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2026-03-01 07:55:12 +0000