Install
docopt
– command line option parser, that will make you smile
docopt is a language for description of command-line
interfaces. This isdocopt
implementation in CoffeeScript, that could
be used for server-side CoffeeScript and JavaScript programs.
Isn't it awesome how modern command-line arguments parsers generate
help message based on your code?!
Hell no! You know what's awesome? It's when the option parser is generated
based on the help message that you write yourself! This way
you don't need to write this stupid repeatable parser-code, and instead can
write a beautiful help message (the way you want it!), which adds readability
to your code.
Now you can write an awesome, readable, clean, DRY code like that:
doc = """
Usage:
quick_example.coffee tcp <host> <port> [--timeout=<seconds>]
quick_example.coffee serial <port> [--baud=9600] [--timeout=<seconds>]
quick_example.coffee -h | --help | --version
"""
{docopt} = require '../docopt'
console.log docopt(doc, version: '0.1.1rc')
Hell yeah! The option parser is generated based on doc
string above, that you
pass to the docopt
function.
API {docopt} = require 'docopt'
###options = docopt(doc, {argv: process.argv[2..], help: true, version: null})
docopt
takes 1 required and 3 optional keyword arguments:
-
doc
should be a string with help message, written according to rules
of docopt language. Here is a quick example of such
a string:Usage: your_program [options] -h --help Show this. -v --verbose Print more text. --quiet Print less text. -o FILE Specify output file [default: ./test.txt].
-
argv
is an optional argument vector; by default it is the argument vector
passed to your program (process.argv[2..]
). You can supply it with an array
of strings (similar toprocess.argv
) e.g. ['--verbose', '-o', 'hai.txt']. -
help
, by defaulttrue
, specifies whether the parser should automatically
print the help message (supplied asdoc
) in case-h
or--help
options
are encountered. After showing the usage-message, the program will terminate.
If you want to handle-h
or--help
options manually (as all other options),
sethelp=false
. -
version
, by defaultnull
, is an optional argument that specifies the
version of your program. If supplied, then, if the parser encounters
--version
option, it will print the supplied version and terminate.
version
could be any printable object, but most likely a string,
e.g.'2.1.0rc1'
.
Note, when docopt
is set to automatically handle -h
, --help
and
--version
options, you still need to mention them in the options description
(doc
) for your users to know about them.
The return value is an Object with properties
(giving long options precedence), e.g:
{'--timeout': '10',
'--baud': '4800',
'--version': false,
'--help': false,
'-h': false,
serial: true,
tcp: false,
'<host>': false,
'<port>': '/dev/ttyr01'}