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# A simple **OptionParser** class to parse option flags from the command-line.
# Use it like so:
# parser = new OptionParser switches, helpBanner
# options = parser.parse process.argv
# The first non-option is considered to be the start of the file (and file
# option) list, and all subsequent arguments are left unparsed.
exports.OptionParser = class OptionParser
# Initialize with a list of valid options, in the form:
# [short-flag, long-flag, description]
# Along with an an optional banner for the usage help.
constructor: (rules, @banner) ->
@rules = buildRules rules
# Parse the list of arguments, populating an `options` object with all of the
# specified options, and return it. `options.arguments` will be an array
# containing the remaining non-option arguments. `options.literals` will be
# an array of options that are meant to be passed through directly to the
# executing script. This is a simpler API than many option parsers that allow
# you to attach callback actions for every flag. Instead, you're responsible
# for interpreting the options object.
parse: (args) ->
options = arguments: [], literals: []
skippingArgument = no
originalArgs = args
args = normalizeArguments args
for arg, i in args
if skippingArgument
skippingArgument = no
if arg is '--'
pos = originalArgs.indexOf '--'
options.arguments = [originalArgs[1 + pos]]
options.literals = originalArgs[(2 + pos)..]
isOption = !!(arg.match(LONG_FLAG) or arg.match(SHORT_FLAG))
matchedRule = no
for rule in @rules
if rule.shortFlag is arg or rule.longFlag is arg
value = if rule.hasArgument
skippingArgument = yes
args[i + 1]
options[] = if rule.isList then (options[] or []).concat value else value
matchedRule = yes
throw new Error "unrecognized option: #{arg}" if isOption and not matchedRule
if not isOption
options.arguments = originalArgs[(originalArgs.indexOf arg)..]
# Return the help text for this **OptionParser**, listing and describing all
# of the valid options, for `--help` and such.
help: ->
lines = []
lines.unshift "#{@banner}\n" if @banner
for rule in @rules
spaces = 15 - rule.longFlag.length
spaces = if spaces > 0 then Array(spaces + 1).join(' ') else ''
letPart = if rule.shortFlag then rule.shortFlag + ', ' else ' '
lines.push ' ' + letPart + rule.longFlag + spaces + rule.description
"\n#{ lines.join('\n') }\n"
# Helpers
# -------
# Regex matchers for option flags.
LONG_FLAG = /^(--\w[\w\-]+)/
SHORT_FLAG = /^(-\w)/
MULTI_FLAG = /^-(\w{2,})/
OPTIONAL = /\[(\w+(\*?))\]/
# Build and return the list of option rules. If the optional *short-flag* is
# unspecified, leave it out by padding with `null`.
buildRules = (rules) ->
for tuple in rules
tuple.unshift null if tuple.length < 3
buildRule tuple...
# Build a rule from a `-o` short flag, a `--output [DIR]` long flag, and the
# description of what the option does.
buildRule = (shortFlag, longFlag, description, options = {}) ->
match = longFlag.match(OPTIONAL)
longFlag = longFlag.match(LONG_FLAG)[1]
name: longFlag.substr 2
shortFlag: shortFlag
longFlag: longFlag
description: description
hasArgument: !!(match and match[1])
isList: !!(match and match[2])
# Normalize arguments by expanding merged flags into multiple flags. This allows
# you to have `-wl` be the same as `--watch --lint`.
normalizeArguments = (args) ->
args = args[..]
result = []
for arg in args
if match = arg.match MULTI_FLAG
result.push '-' + l for l in match[1].split ''
result.push arg
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