// 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" "exp/ebnf" "flag" "fmt" "go/scanner" "go/token" "io" "io/ioutil" "os" "path/filepath" ) var fset = token.NewFileSet() var start = flag.String("start", "Start", "name of start production") func usage() { fmt.Fprintf(os.Stderr, "usage: go tool ebnflint [flags] [filename]\n") flag.PrintDefaults() os.Exit(1) } // Markers around EBNF sections in .html files var ( open = []byte(`
`)
	close = []byte(`
`) ) func report(err error) { scanner.PrintError(os.Stderr, err) os.Exit(1) } 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:], close) // close marker if j < 0 { j = len(src) - i } j += i // copy EBNF text buf.Write(src[i:j]) // advance src = src[j:] } return buf.Bytes() } func main() { flag.Parse() var ( name string r io.Reader ) switch flag.NArg() { case 0: name, r = "", os.Stdin case 1: name = flag.Arg(0) default: usage() } if err := verify(name, *start, r); err != nil { report(err) } } func verify(name, start string, r io.Reader) error { if r == nil { f, err := os.Open(name) if err != nil { return err } defer f.Close() r = f } src, err := ioutil.ReadAll(r) if err != nil { return err } if filepath.Ext(name) == ".html" || bytes.Index(src, open) >= 0 { src = extractEBNF(src) } grammar, err := ebnf.Parse(name, bytes.NewBuffer(src)) if err != nil { return err } return ebnf.Verify(grammar, start) }