111 lines
2.7 KiB
Go
111 lines
2.7 KiB
Go
package main
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import (
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"fmt"
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"os"
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scanner "github.com/dotcloud/docker/pkg/dockerscript"
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"strings"
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)
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func main() {
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s := &scanner.Scanner{}
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s.Init(os.Stdin)
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s.Whitespace = 1<<'\t' | 1<<' '
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//s.Mode = ScanIdents | ScanFloats | ScanChars | ScanStrings | ScanRawStrings | ScanComments | SkipComments
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s.Mode = scanner.ScanStrings | scanner.ScanRawStrings | scanner.ScanIdents
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expr, err := parse(s, "")
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if err != nil {
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fmt.Fprintf(os.Stderr, "line %d:%d: %v\n", s.Pos().Line, s.Pos().Column, err)
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os.Exit(1)
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}
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fmt.Printf("%d commands:\n", len(expr))
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for i, cmd := range expr {
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fmt.Printf("%%%d: %s\n", i, cmd)
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}
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}
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type Command struct {
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Args []string
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Children []*Command
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}
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func (cmd *Command) subString(depth int) string {
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var prefix string
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for i:=0; i<depth; i++ {
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prefix += " "
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}
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s := prefix + strings.Join(cmd.Args, ", ")
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if len(cmd.Children) > 0 {
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s += " {\n"
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for _, subcmd := range cmd.Children {
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s += subcmd.subString(depth + 1)
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}
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s += prefix + "}"
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}
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s += "\n"
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return s
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}
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func (cmd *Command) String() string {
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return cmd.subString(0)
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}
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func parseArgs(s *scanner.Scanner) ([]string, rune, error) {
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var parseError error
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// FIXME: we overwrite previously set error
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s.Error = func(s *scanner.Scanner, msg string) {
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parseError = fmt.Errorf(msg)
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// parseError = fmt.Errorf("line %d:%d: %s\n", s.Pos().Line, s.Pos().Column, msg)
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}
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var args []string
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tok := s.Scan()
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for tok != scanner.EOF {
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if parseError != nil {
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return args, tok, parseError
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}
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text := s.TokenText()
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//fmt.Printf("--> [%s]\n", text)
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if text == "{" || text == "}" || text == "\n" || text == "\r" || text == ";" {
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return args, tok, nil
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}
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args = append(args, text)
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tok = s.Scan()
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}
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return args, tok, nil
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}
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func parse(s *scanner.Scanner, opener string) (expr []*Command, err error) {
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defer func() {
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fmt.Printf("parse() returned %d commands:\n", len(expr))
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for _, c := range expr {
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fmt.Printf("\t----> %s\n", c)
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}
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}()
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for {
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args, tok, err := parseArgs(s)
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if err != nil {
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return nil, err
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}
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cmd := &Command{Args: args}
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fmt.Printf("---> args=%v finished by %s\n", args, s.TokenText())
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afterArgs := s.TokenText()
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if afterArgs == "{" {
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fmt.Printf("---> therefore calling parse() of sub-expression\n")
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children, err := parse(s, "{")
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fmt.Printf("---> parse() of sub-epxression returned %d commands (ended by %s) and error=%v\n", children, s.TokenText(), err)
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if err != nil {
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return nil, err
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}
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cmd.Children = children
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} else if afterArgs == "}" && opener != "{" {
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return nil, fmt.Errorf("unexpected end of block '}'")
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}
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if len(cmd.Args) > 0 || len(cmd.Children) > 0 {
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expr = append(expr, cmd)
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}
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if tok == scanner.EOF || afterArgs == "}" {
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break
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}
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}
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return expr, nil
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}
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