mirror of https://github.com/cheat/cheat.git
576 lines
15 KiB
Go
576 lines
15 KiB
Go
// Licensed under terms of MIT license (see LICENSE-MIT)
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// Copyright (c) 2013 Keith Batten, kbatten@gmail.com
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// Copyright (c) 2016 David Irvine
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package docopt
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import (
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"fmt"
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"os"
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"regexp"
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"strings"
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)
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type Parser struct {
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// HelpHandler is called when we encounter bad user input, or when the user
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// asks for help.
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// By default, this calls os.Exit(0) if it handled a built-in option such
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// as -h, --help or --version. If the user errored with a wrong command or
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// options, we exit with a return code of 1.
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HelpHandler func(err error, usage string)
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// OptionsFirst requires that option flags always come before positional
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// arguments; otherwise they can overlap.
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OptionsFirst bool
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// SkipHelpFlags tells the parser not to look for -h and --help flags and
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// call the HelpHandler.
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SkipHelpFlags bool
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}
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var PrintHelpAndExit = func(err error, usage string) {
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if err != nil {
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fmt.Fprintln(os.Stderr, usage)
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os.Exit(1)
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} else {
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fmt.Println(usage)
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os.Exit(0)
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}
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}
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var PrintHelpOnly = func(err error, usage string) {
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if err != nil {
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fmt.Fprintln(os.Stderr, usage)
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} else {
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fmt.Println(usage)
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}
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}
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var NoHelpHandler = func(err error, usage string) {}
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var DefaultParser = &Parser{
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HelpHandler: PrintHelpAndExit,
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OptionsFirst: false,
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SkipHelpFlags: false,
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}
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// ParseDoc parses os.Args[1:] based on the interface described in doc, using the default parser options.
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func ParseDoc(doc string) (Opts, error) {
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return ParseArgs(doc, nil, "")
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}
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// ParseArgs parses custom arguments based on the interface described in doc. If you provide a non-empty version
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// string, then this will be displayed when the --version flag is found. This method uses the default parser options.
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func ParseArgs(doc string, argv []string, version string) (Opts, error) {
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return DefaultParser.ParseArgs(doc, argv, version)
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}
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// ParseArgs parses custom arguments based on the interface described in doc. If you provide a non-empty version
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// string, then this will be displayed when the --version flag is found.
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func (p *Parser) ParseArgs(doc string, argv []string, version string) (Opts, error) {
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return p.parse(doc, argv, version)
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}
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// Deprecated: Parse is provided for backward compatibility with the original docopt.go package.
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// Please rather make use of ParseDoc, ParseArgs, or use your own custom Parser.
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func Parse(doc string, argv []string, help bool, version string, optionsFirst bool, exit ...bool) (map[string]interface{}, error) {
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exitOk := true
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if len(exit) > 0 {
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exitOk = exit[0]
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}
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p := &Parser{
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OptionsFirst: optionsFirst,
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SkipHelpFlags: !help,
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}
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if exitOk {
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p.HelpHandler = PrintHelpAndExit
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} else {
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p.HelpHandler = PrintHelpOnly
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}
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return p.parse(doc, argv, version)
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}
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func (p *Parser) parse(doc string, argv []string, version string) (map[string]interface{}, error) {
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if argv == nil {
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argv = os.Args[1:]
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}
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if p.HelpHandler == nil {
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p.HelpHandler = DefaultParser.HelpHandler
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}
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args, output, err := parse(doc, argv, !p.SkipHelpFlags, version, p.OptionsFirst)
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if _, ok := err.(*UserError); ok {
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// the user gave us bad input
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p.HelpHandler(err, output)
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} else if len(output) > 0 && err == nil {
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// the user asked for help or --version
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p.HelpHandler(err, output)
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}
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return args, err
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}
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// -----------------------------------------------------------------------------
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// parse and return a map of args, output and all errors
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func parse(doc string, argv []string, help bool, version string, optionsFirst bool) (args map[string]interface{}, output string, err error) {
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if argv == nil && len(os.Args) > 1 {
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argv = os.Args[1:]
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}
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usageSections := parseSection("usage:", doc)
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if len(usageSections) == 0 {
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err = newLanguageError("\"usage:\" (case-insensitive) not found.")
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return
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}
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if len(usageSections) > 1 {
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err = newLanguageError("More than one \"usage:\" (case-insensitive).")
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return
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}
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usage := usageSections[0]
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options := parseDefaults(doc)
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formal, err := formalUsage(usage)
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if err != nil {
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output = handleError(err, usage)
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return
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}
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pat, err := parsePattern(formal, &options)
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if err != nil {
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output = handleError(err, usage)
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return
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}
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patternArgv, err := parseArgv(newTokenList(argv, errorUser), &options, optionsFirst)
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if err != nil {
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output = handleError(err, usage)
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return
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}
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patFlat, err := pat.flat(patternOption)
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if err != nil {
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output = handleError(err, usage)
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return
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}
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patternOptions := patFlat.unique()
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patFlat, err = pat.flat(patternOptionSSHORTCUT)
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if err != nil {
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output = handleError(err, usage)
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return
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}
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for _, optionsShortcut := range patFlat {
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docOptions := parseDefaults(doc)
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optionsShortcut.children = docOptions.unique().diff(patternOptions)
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}
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if output = extras(help, version, patternArgv, doc); len(output) > 0 {
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return
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}
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err = pat.fix()
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if err != nil {
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output = handleError(err, usage)
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return
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}
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matched, left, collected := pat.match(&patternArgv, nil)
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if matched && len(*left) == 0 {
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patFlat, err = pat.flat(patternDefault)
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if err != nil {
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output = handleError(err, usage)
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return
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}
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args = append(patFlat, *collected...).dictionary()
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return
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}
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err = newUserError("")
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output = handleError(err, usage)
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return
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}
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func handleError(err error, usage string) string {
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if _, ok := err.(*UserError); ok {
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return strings.TrimSpace(fmt.Sprintf("%s\n%s", err, usage))
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}
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return ""
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}
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func parseSection(name, source string) []string {
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p := regexp.MustCompile(`(?im)^([^\n]*` + name + `[^\n]*\n?(?:[ \t].*?(?:\n|$))*)`)
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s := p.FindAllString(source, -1)
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if s == nil {
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s = []string{}
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}
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for i, v := range s {
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s[i] = strings.TrimSpace(v)
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}
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return s
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}
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func parseDefaults(doc string) patternList {
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defaults := patternList{}
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p := regexp.MustCompile(`\n[ \t]*(-\S+?)`)
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for _, s := range parseSection("options:", doc) {
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// FIXME corner case "bla: options: --foo"
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_, _, s = stringPartition(s, ":") // get rid of "options:"
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split := p.Split("\n"+s, -1)[1:]
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match := p.FindAllStringSubmatch("\n"+s, -1)
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for i := range split {
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optionDescription := match[i][1] + split[i]
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if strings.HasPrefix(optionDescription, "-") {
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defaults = append(defaults, parseOption(optionDescription))
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}
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}
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}
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return defaults
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}
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func parsePattern(source string, options *patternList) (*pattern, error) {
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tokens := tokenListFromPattern(source)
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result, err := parseExpr(tokens, options)
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if err != nil {
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return nil, err
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}
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if tokens.current() != nil {
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return nil, tokens.errorFunc("unexpected ending: %s" + strings.Join(tokens.tokens, " "))
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}
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return newRequired(result...), nil
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}
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func parseArgv(tokens *tokenList, options *patternList, optionsFirst bool) (patternList, error) {
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/*
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Parse command-line argument vector.
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If options_first:
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argv ::= [ long | shorts ]* [ argument ]* [ '--' [ argument ]* ] ;
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else:
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argv ::= [ long | shorts | argument ]* [ '--' [ argument ]* ] ;
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*/
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parsed := patternList{}
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for tokens.current() != nil {
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if tokens.current().eq("--") {
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for _, v := range tokens.tokens {
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parsed = append(parsed, newArgument("", v))
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}
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return parsed, nil
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} else if tokens.current().hasPrefix("--") {
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pl, err := parseLong(tokens, options)
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if err != nil {
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return nil, err
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}
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parsed = append(parsed, pl...)
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} else if tokens.current().hasPrefix("-") && !tokens.current().eq("-") {
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ps, err := parseShorts(tokens, options)
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if err != nil {
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return nil, err
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}
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parsed = append(parsed, ps...)
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} else if optionsFirst {
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for _, v := range tokens.tokens {
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parsed = append(parsed, newArgument("", v))
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}
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return parsed, nil
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} else {
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parsed = append(parsed, newArgument("", tokens.move().String()))
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}
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}
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return parsed, nil
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}
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func parseOption(optionDescription string) *pattern {
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optionDescription = strings.TrimSpace(optionDescription)
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options, _, description := stringPartition(optionDescription, " ")
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options = strings.Replace(options, ",", " ", -1)
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options = strings.Replace(options, "=", " ", -1)
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short := ""
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long := ""
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argcount := 0
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var value interface{}
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value = false
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reDefault := regexp.MustCompile(`(?i)\[default: (.*)\]`)
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for _, s := range strings.Fields(options) {
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if strings.HasPrefix(s, "--") {
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long = s
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} else if strings.HasPrefix(s, "-") {
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short = s
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} else {
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argcount = 1
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}
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if argcount > 0 {
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matched := reDefault.FindAllStringSubmatch(description, -1)
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if len(matched) > 0 {
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value = matched[0][1]
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} else {
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value = nil
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}
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}
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}
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return newOption(short, long, argcount, value)
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}
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func parseExpr(tokens *tokenList, options *patternList) (patternList, error) {
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// expr ::= seq ( '|' seq )* ;
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seq, err := parseSeq(tokens, options)
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if err != nil {
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return nil, err
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}
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if !tokens.current().eq("|") {
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return seq, nil
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}
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var result patternList
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if len(seq) > 1 {
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result = patternList{newRequired(seq...)}
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} else {
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result = seq
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}
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for tokens.current().eq("|") {
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tokens.move()
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seq, err = parseSeq(tokens, options)
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if err != nil {
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return nil, err
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}
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if len(seq) > 1 {
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result = append(result, newRequired(seq...))
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} else {
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result = append(result, seq...)
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}
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}
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if len(result) > 1 {
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return patternList{newEither(result...)}, nil
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}
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return result, nil
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}
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func parseSeq(tokens *tokenList, options *patternList) (patternList, error) {
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// seq ::= ( atom [ '...' ] )* ;
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result := patternList{}
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for !tokens.current().match(true, "]", ")", "|") {
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atom, err := parseAtom(tokens, options)
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if err != nil {
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return nil, err
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}
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if tokens.current().eq("...") {
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atom = patternList{newOneOrMore(atom...)}
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tokens.move()
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}
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result = append(result, atom...)
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}
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return result, nil
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}
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func parseAtom(tokens *tokenList, options *patternList) (patternList, error) {
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// atom ::= '(' expr ')' | '[' expr ']' | 'options' | long | shorts | argument | command ;
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tok := tokens.current()
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result := patternList{}
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if tokens.current().match(false, "(", "[") {
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tokens.move()
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var matching string
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pl, err := parseExpr(tokens, options)
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if err != nil {
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return nil, err
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}
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if tok.eq("(") {
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matching = ")"
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result = patternList{newRequired(pl...)}
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} else if tok.eq("[") {
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matching = "]"
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result = patternList{newOptional(pl...)}
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}
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moved := tokens.move()
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if !moved.eq(matching) {
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return nil, tokens.errorFunc("unmatched '%s', expected: '%s' got: '%s'", tok, matching, moved)
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}
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return result, nil
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} else if tok.eq("options") {
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tokens.move()
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return patternList{newOptionsShortcut()}, nil
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} else if tok.hasPrefix("--") && !tok.eq("--") {
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return parseLong(tokens, options)
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} else if tok.hasPrefix("-") && !tok.eq("-") && !tok.eq("--") {
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return parseShorts(tokens, options)
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} else if tok.hasPrefix("<") && tok.hasSuffix(">") || tok.isUpper() {
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return patternList{newArgument(tokens.move().String(), nil)}, nil
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}
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return patternList{newCommand(tokens.move().String(), false)}, nil
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}
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func parseLong(tokens *tokenList, options *patternList) (patternList, error) {
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// long ::= '--' chars [ ( ' ' | '=' ) chars ] ;
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long, eq, v := stringPartition(tokens.move().String(), "=")
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var value interface{}
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var opt *pattern
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if eq == "" && v == "" {
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value = nil
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} else {
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value = v
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}
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if !strings.HasPrefix(long, "--") {
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return nil, newError("long option '%s' doesn't start with --", long)
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}
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similar := patternList{}
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for _, o := range *options {
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if o.long == long {
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similar = append(similar, o)
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}
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}
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if tokens.err == errorUser && len(similar) == 0 { // if no exact match
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similar = patternList{}
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for _, o := range *options {
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if strings.HasPrefix(o.long, long) {
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similar = append(similar, o)
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}
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}
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}
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if len(similar) > 1 { // might be simply specified ambiguously 2+ times?
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similarLong := make([]string, len(similar))
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for i, s := range similar {
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similarLong[i] = s.long
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}
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return nil, tokens.errorFunc("%s is not a unique prefix: %s?", long, strings.Join(similarLong, ", "))
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} else if len(similar) < 1 {
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argcount := 0
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if eq == "=" {
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argcount = 1
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}
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opt = newOption("", long, argcount, false)
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*options = append(*options, opt)
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if tokens.err == errorUser {
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var val interface{}
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if argcount > 0 {
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val = value
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} else {
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val = true
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}
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opt = newOption("", long, argcount, val)
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}
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} else {
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opt = newOption(similar[0].short, similar[0].long, similar[0].argcount, similar[0].value)
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if opt.argcount == 0 {
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if value != nil {
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return nil, tokens.errorFunc("%s must not have an argument", opt.long)
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}
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} else {
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if value == nil {
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if tokens.current().match(true, "--") {
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return nil, tokens.errorFunc("%s requires argument", opt.long)
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}
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moved := tokens.move()
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if moved != nil {
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value = moved.String() // only set as string if not nil
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}
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}
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}
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if tokens.err == errorUser {
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if value != nil {
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opt.value = value
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} else {
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opt.value = true
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}
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}
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}
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return patternList{opt}, nil
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}
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func parseShorts(tokens *tokenList, options *patternList) (patternList, error) {
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// shorts ::= '-' ( chars )* [ [ ' ' ] chars ] ;
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tok := tokens.move()
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if !tok.hasPrefix("-") || tok.hasPrefix("--") {
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return nil, newError("short option '%s' doesn't start with -", tok)
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}
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left := strings.TrimLeft(tok.String(), "-")
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parsed := patternList{}
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for left != "" {
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var opt *pattern
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short := "-" + left[0:1]
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left = left[1:]
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similar := patternList{}
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for _, o := range *options {
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if o.short == short {
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similar = append(similar, o)
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}
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}
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if len(similar) > 1 {
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return nil, tokens.errorFunc("%s is specified ambiguously %d times", short, len(similar))
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} else if len(similar) < 1 {
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opt = newOption(short, "", 0, false)
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*options = append(*options, opt)
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if tokens.err == errorUser {
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opt = newOption(short, "", 0, true)
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}
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} else { // why copying is necessary here?
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opt = newOption(short, similar[0].long, similar[0].argcount, similar[0].value)
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var value interface{}
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if opt.argcount > 0 {
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if left == "" {
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if tokens.current().match(true, "--") {
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return nil, tokens.errorFunc("%s requires argument", short)
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}
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value = tokens.move().String()
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} else {
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value = left
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left = ""
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}
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}
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if tokens.err == errorUser {
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if value != nil {
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opt.value = value
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} else {
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opt.value = true
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}
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}
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}
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parsed = append(parsed, opt)
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}
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return parsed, nil
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}
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func formalUsage(section string) (string, error) {
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_, _, section = stringPartition(section, ":") // drop "usage:"
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pu := strings.Fields(section)
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if len(pu) == 0 {
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return "", newLanguageError("no fields found in usage (perhaps a spacing error).")
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}
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result := "( "
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for _, s := range pu[1:] {
|
|
if s == pu[0] {
|
|
result += ") | ( "
|
|
} else {
|
|
result += s + " "
|
|
}
|
|
}
|
|
result += ")"
|
|
|
|
return result, nil
|
|
}
|
|
|
|
func extras(help bool, version string, options patternList, doc string) string {
|
|
if help {
|
|
for _, o := range options {
|
|
if (o.name == "-h" || o.name == "--help") && o.value == true {
|
|
return strings.Trim(doc, "\n")
|
|
}
|
|
}
|
|
}
|
|
if version != "" {
|
|
for _, o := range options {
|
|
if (o.name == "--version") && o.value == true {
|
|
return version
|
|
}
|
|
}
|
|
}
|
|
return ""
|
|
}
|
|
|
|
func stringPartition(s, sep string) (string, string, string) {
|
|
sepPos := strings.Index(s, sep)
|
|
if sepPos == -1 { // no seperator found
|
|
return s, "", ""
|
|
}
|
|
split := strings.SplitN(s, sep, 2)
|
|
return split[0], sep, split[1]
|
|
}
|