--- /dev/null
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+ "bytes";
+ "ebnf";
+ "flag";
+ "fmt";
+ "io";
+ "os";
+ "path";
+ "sort";
+ "strings";
+)
+
+
+var start = flag.String("start", "Start", "name of start production");
+
+
+func usage() {
+ fmt.Fprintf(os.Stderr, "usage: ebnflint [flags] [filename]\n");
+ flag.PrintDefaults();
+ os.Exit(1);
+}
+
+
+// Markers around EBNF sections in .html files
+var (
+ open = strings.Bytes(`<pre class="ebnf">`);
+ close = strings.Bytes(`</pre>`);
+)
+
+
+func extractEBNF(src []byte) []byte {
+ var buf bytes.Buffer;
+
+ for i, j, n := 0, 0, len(src); ; {
+ // i = beginning of EBNF section
+ i = bytes.Index(src[j : n], open);
+ if i < 0 {
+ break;
+ }
+ i += j+len(open);
+
+ // write as many newlines as found in the excluded text
+ // to maintain correct line numbers in error messages
+ for _, ch := range src[j : i] {
+ if ch == '\n' {
+ buf.WriteByte('\n');
+ }
+ }
+
+ // j = end of EBNF section
+ j = bytes.Index(src[i : n], close);
+ if j < 0 {
+ // missing closing
+ // TODO(gri) should this be an error?
+ j = n-i;
+ }
+ j += i;
+
+ // copy EBNF section
+ buf.Write(src[i : j]);
+ }
+
+ return buf.Data();
+}
+
+
+// TODO(gri) This is the same code for reportError as in gofmt.
+// Should factor this out as part of some parsing framework
+// that could also deal with reading various input sources.
+
+func reportError(filename string, err os.Error) {
+ if errors, ok := err.(ebnf.ErrorList); ok {
+ sort.Sort(errors);
+ for _, e := range errors {
+ fmt.Fprintf(os.Stderr, "%s:%v\n", filename, e);
+ }
+ } else {
+ fmt.Fprintf(os.Stderr, "%s: %v\n", filename, err);
+ }
+ os.Exit(1);
+}
+
+
+func main() {
+ flag.Parse();
+
+ var filename string;
+ switch flag.NArg() {
+ case 0:
+ filename = "/dev/stdin";
+ case 1:
+ filename = flag.Arg(0);
+ default:
+ usage();
+ }
+
+ src, err := io.ReadFile(filename);
+ if err != nil {
+ reportError(filename, err);
+ }
+
+ if path.Ext(filename) == ".html" {
+ src = extractEBNF(src);
+ }
+
+ grammar, err := ebnf.Parse(src);
+ if err != nil {
+ reportError(filename, err);
+ }
+
+ if err = ebnf.Verify(grammar, *start); err != nil {
+ reportError(filename, err);
+ }
+}