Subversion Repositories openrisc

// 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)

}