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// 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";
"go/scanner";
"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 = beginning of EBNF text
i := bytes.Index(src, open);
if i < 0 {
break; // no EBNF found - we are done
}
i += len(open);
// write as many newlines as found in the excluded text
// to maintain correct line numbers in error messages
for _, ch := range src[0 : i] {
if ch == '\n' {
buf.WriteByte('\n');
}
}
// j = end of EBNF text (or end of source)
j := bytes.Index(src[i : len(src)], close); // close marker
if j < 0 {
j = len(src)-i;
}
j += i;
// copy EBNF text
buf.Write(src[i : j]);
// advance
src = src[j : len(src)];
}
return buf.Data();
}
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 {
scanner.PrintError(os.Stderr, err);
}
if path.Ext(filename) == ".html" {
src = extractEBNF(src);
}
grammar, err := ebnf.Parse(filename, src);
if err != nil {
scanner.PrintError(os.Stderr, err);
}
if err = ebnf.Verify(grammar, *start); err != nil {
scanner.PrintError(os.Stderr, err);
}
}
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