NAME
main.rb
SYNOPSIS
a class factory and dsl for generating command line programs real quick
URI
http://rubyforge.org/projects/codeforpeople/
http://codeforpeople.com/lib/ruby/
INSTALL
gem install main
DESCRIPTION
main.rb features the following:
- unification of option, argument, keyword, and environment parameter
parsing
- auto generation of usage and help messages
- support for mode/sub-commands
- io redirection support
- logging hooks using ruby's built-in logging mechanism
- intelligent error handling and exit codes
- use as dsl or library for building Main objects
- parsing user defined ARGV and ENV
- zero requirements for understanding the obtuse apis of *any* command
line option parsers
in short main.rb aims to drastically lower the barrier to writing uniform
command line applications.
for instance, this program
require 'main'
Main {
argument 'foo'
option 'bar'
def run
p params['foo']
p params['bar']
exit_success!
end
}
sets up a program which requires one argument, 'bar', and which may accept one
command line switch, '--foo' in addition to the single option/mode which is always
accepted and handled appropriately: 'help', '--help', '-h'. for the most
part main.rb stays out of your command line namespace but insists that your
application has at least a help mode/option.
main.rb supports sub-commands in a very simple way
require 'main'
Main {
mode 'install' do
def run() puts 'installing...' end
end
mode 'uninstall' do
def run() puts 'uninstalling...' end
end
}
which allows you a program called 'a.rb' to be invoked as
ruby a.rb install
and
ruby a.rb uninstall
for simple programs main.rb is a real time saver but it's for more complex
applications where main.rb's unification of parameter parsing, class
configuration dsl, and auto-generation of usage messages can really streamline
command line application development. for example the following 'a.rb'
program:
require 'main'
Main {
argument('foo'){
cast :int
}
keyword('bar'){
arity 2
cast :float
defaults 0.0, 1.0
}
option('foobar'){
argument :optional
description 'the foobar option is very handy'
}
environment('BARFOO'){
cast :list_of_bool
synopsis 'export barfoo=value'
}
def run
p params['foo'].value
p params['bar'].values
p params['foobar'].value
p params['BARFOO'].value
end
}
when run with a command line of
BARFOO=true,false,false ruby a.rb 42 bar=40 bar=2 --foobar=a
will produce
42
[40.0, 2.0]
"a"
[true, false, false]
while a command line of
ruby a.rb --help
will produce
NAME
a.rb
SYNOPSIS
a.rb foo [bar=bar] [options]+
PARAMETERS
* foo [ 1 -> int(foo) ]
* bar=bar [ 2 ~> float(bar=0.0,1.0) ]
* --foobar=[foobar] [ 1 ~> foobar ]
the foobar option is very handy
* --help, -h
* export barfoo=value
and this shows how all of argument, keyword, option, and environment parsing
can be declartively dealt with in a unified fashion - the dsl for all
parameter types is the same - and how auto synopsis and usage generation saves
keystrokes. the parameter synopsis is compact and can be read as
* foo [ 1 -> int(foo) ]
'one argument will get processed via int(argument_name)'
1 : one argument
-> : will get processed (the argument is required)
int(foo) : the cast is int, the arg name is foo
* bar=bar [ 2 ~> float(bar=0.0,1.0) ]
'two keyword arguments might be processed via float(bar=0.0,1.0)'
2 : two arguments
~> : might be processed (the argument is optional)
float(bar=0.0,1.0) : the cast will be float, the default values are
0.0 and 1.0
* --foobar=[foobar] [ 1 ~> foobar ]
'one option with optional argument may be given directly'
* --help, -h
no synopsis, simple switch takes no args and is not required
* export barfoo=value
a user defined synopsis
SAMPLES
<========< samples/a.rb >========>
~ > cat samples/a.rb
require 'main'
ARGV.replace %w( 42 ) if ARGV.empty?
Main {
argument('foo'){
required # this is the default
cast :int # value cast to Fixnum
validate{|foo| foo == 42} # raises error in failure case
description 'the foo param' # shown in --help
}
def run
p params['foo'].given?
p params['foo'].value
end
}
~ > ruby samples/a.rb
true
42
~ > ruby samples/a.rb --help
NAME
a.rb
SYNOPSIS
a.rb foo [options]+
PARAMETERS
foo (1 -> int(foo))
the foo param
--help, -h
<========< samples/b.rb >========>
~ > cat samples/b.rb
require 'main'
ARGV.replace %w( 40 1 1 ) if ARGV.empty?
Main {
argument('foo'){
arity 3 # foo will given three times
cast :int # value cast to Fixnum
validate{|foo| [40,1].include? foo} # raises error in failure case
description 'the foo param' # shown in --help
}
def run
p params['foo'].given?
p params['foo'].values
end
}
~ > ruby samples/b.rb
true
[40, 1, 1]
~ > ruby samples/b.rb --help
NAME
b.rb
SYNOPSIS
b.rb foo [options]+
PARAMETERS
foo (3 -> int(foo))
the foo param
--help, -h
<========< samples/c.rb >========>
~ > cat samples/c.rb
require 'main'
ARGV.replace %w( foo=40 foo=2 bar=false ) if ARGV.empty?
Main {
keyword('foo'){
required # by default keywords are not required
arity 2
cast :float
}
keyword('bar'){
cast :bool
}
def run
p params['foo'].given?
p params['foo'].values
p params['bar'].given?
p params['bar'].value
end
}
~ > ruby samples/c.rb
true
[40.0, 2.0]
true
false
~ > ruby samples/c.rb --help
NAME
c.rb
SYNOPSIS
c.rb foo=foo [bar=bar] [options]+
PARAMETERS
foo=foo (2 -> float(foo))
bar=bar (1 ~> bool(bar))
--help, -h
<========< samples/d.rb >========>
~ > cat samples/d.rb
require 'main'
ARGV.replace %w( --foo=40 -f2 ) if ARGV.empty?
Main {
option('foo', 'f'){
required # by default options are not required, we could use 'foo=foo'
# above as a shortcut
argument_required
arity 2
cast :float
}
option('bar=[bar]', 'b'){ # note shortcut syntax for optional args
# argument_optional # we could also use this method
cast :bool
default false
}
def run
p params['foo'].given?
p params['foo'].values
p params['bar'].given?
p params['bar'].value
end
}
~ > ruby samples/d.rb
true
[40.0, 2.0]
nil
false
~ > ruby samples/d.rb --help
NAME
d.rb
SYNOPSIS
d.rb --foo=foo [options]+
PARAMETERS
--foo=foo, -f (2 -> float(foo))
--bar=[bar], -b (1 ~> bool(bar=false))
--help, -h
DOCS
test/main.rb
vim -o lib/main.rb lib/main/*
API section below
HISTORY
2.1.0
- added custom error handling dsl for parameters, this includes the ability
to prepend, append, or replace the standard error handlers:
require 'main'
Main {
argument 'x' do
error :before do
puts 'this fires *before* normal error handling using #instance_eval...'
end
error do
puts 'this fires *instead of* normal error handling using #instance_eval...'
end
error :after do
puts 'this fires *after* normal error handling using #instance_eval...'
end
end
run(){ p param['x'].given? }
}
- added ability to exit at any time bypassing *all* error handling using
'throw :exit, 42' where 42 is the desired exit status. throw without a
status simply exits with 0.
- added 'help!' method which simply dumps out usage and exits
2.0.0
- removed need for proxy.rb via Main::Base.wrap_run!
- added error handling hooks for parameter parsing
- bundled arrayfields, attributes, and pervasives although gems are tried
first
- softened error messages for parameter parsing errors: certain classes of
errors are now 'softspoken' and print only the message, not the entire
stacktrace, to stderr. much nicer for users. this is configurable.
- added subcommand/mode support
- added support for user defined exception handling on top level
exceptions/exits
- added support for negative arity. this users ruby's own arity
semantics, for example:
lambda{|*a|}.arity == -1
lambda{|a,*b|}.arity == -2
lambda{|a,b,*c|}.arity == -3
...
in otherwords parameters now support 'zero or more', 'one or more' ...
'n or more' argument semantics
1.0.0
- some improved usage messages from jeremy hinegardner
0.0.2
- removed dependancy on attributes/arrayfields. main now has zero gem
dependancies.
- added support for io redirection. redirection of stdin, stdout, and
stderr can be done to any io like object or object that can be
inerpreted as a pathname (object.to_s)
- main objects can now easily be created and run on demand, which makes
testing a breeze
def test_unit_goodness!
main =
Main.new{
stdout StringIO.new
stderr '/dev/null'
def run
puts 42
end
}
main.run
main.stdout.rewind
assert main.stdout.read == "42\n"
end
- added API section to readme and called it 'docs'
- wrote a bunch more tests. there are now 42 of them.
0.0.1
initial version. this version extracts much of the functionality of alib's
(gen install alib) Alib.script main program generator and also some of jim's
freeze's excellent CommandLine::Aplication into what i hope is a simpler and
more unified interface
API
Main {
###########################################################################
# CLASS LEVEL API #
###########################################################################
#
# the name of the program, auto-set and used in usage
#
program 'foo.rb'
#
# a short description of program functionality, auto-set and used in usage
#
synopsis "foo.rb arg [options]+"
#
# long description of program functionality, used in usage iff set
#
description <<-hdoc
this text will automatically be indented to the right level.
it should describe how the program works in detail
hdoc
#
# used in usage iff set
#
author '[email protected]'
#
# used in usage
#
version '0.0.42'
#
# stdin/out/err can be anthing which responds to read/write or a string
# which will be opened as in the appropriate mode
#
stdin '/dev/null'
stdout '/dev/null'
stderr open('/dev/null', 'w')
#
# the logger should be a Logger object, something 'write'-able, or a string
# which will be used to open the logger. the logger_level specifies the
# initalize verbosity setting, the default is Logger::INFO
#
logger(( program + '.log' ))
logger_level Logger::DEBUG
#
# you can configure exit codes. the defaults are shown
#
exit_success # 0
exit_failure # 1
exit_warn # 42
#
# the usage object is rather complex. by default it's an object which can
# be built up in sections using the
#
# usage["BUGS"] = "something about bugs'
#
# syntax to append sections onto the already pre-built usage message which
# contains program, synopsis, parameter descriptions and the like
#
# however, you always replace the usage object wholesale with one of your
# chosing like so
#
usage <<-txt
my own usage message
txt
###########################################################################
# MODE API #
###########################################################################
#
# modes are class factories that inherit from their parent class. they can
# be nested *arbitrarily* deep. usage messages are tailored for each mode.
# modes are, for the most part, independant classes but parameters are
# always a superset of the parent class - a mode accepts all of it's parents
# paramters *plus* and additional ones
#
option 'inherited-option'
argument 'inherited-argument'
mode 'install' do
option 'force' do
description 'clobber existing installation'
end
def run
inherited_method()
puts 'installing...'
end
mode 'docs' do
description 'installs the docs'
def run
puts 'installing docs...'
end
end
end
mode 'un-install' do
option 'force' do
description 'remove even if dependancies exist'
end
def run
inherited_method()
puts 'un-installing...'
end
end
def run
puts 'no mode yo?'
end
def inherited_method
puts 'superclass_method...'
end
###########################################################################
# PARAMETER API #
###########################################################################
#
# all the parameter types of argument|keyword|option|environment share this
# api. you must specify the type when the parameter method is used.
# alternatively used one of the shortcut methods
# argument|keyword|option|environment. in otherwords
#
# parameter('foo'){ type :option }
#
# is synonymous with
#
# option('foo'){ }
#
option 'foo' {
#
# required - whether this paramter must by supplied on the command line.
# note that you can create 'required' options with this keyword
#
required # or required true
#
# argument_required - applies only to options.
#
argument_required # argument :required
#
# argument_optional - applies only to options.
#
argument_optional # argument :optional
#
# cast - should be either a lambda taking one argument, or a symbol
# designation one of the built in casts defined in Main::Cast. supported
# types are :boolean|:integer|:float|:numeric|:string|:uri. built-in
# casts can be abbreviated
#
cast :int
#
# validate - should be a lambda taking one argument and returning
# true|false
#
validate{|int| int == 42}
#
# synopsis - should be a concise characterization of the paramter. a
# default synopsis is built automatically from the parameter. this
# information is displayed in the usage message
#
synopsis '--foo'
#
# description - a longer description of the paramter. it appears in the
# usage also.
#
description 'a long description of foo'
#
# arity - indicates how many times the parameter should appear on the
# command line. the default is one. negative arities are supported and
# follow the same rules as ruby methods/procs.
#
arity 2
#
# default - you can provide a default value in case none is given. the
# alias 'defaults' reads a bit nicer when you are giving a list of
# defaults for paramters of > 1 arity
#
defaults 40, 2
#
# you can add custom per-parameter error handlers using the following
#
error :before do
puts 'this fires *before* normal error handling using #instance_eval...'
end
error do
puts 'this fires *instead of* normal error handling using #instance_eval...'
end
error :after do
puts 'this fires *after* normal error handling using #instance_eval...'
end
}
###########################################################################
# INSTANCE LEVEL API #
###########################################################################
#
# you must define a run method. it is the only method you must define.
#
def run
#
# all parameters are available in the 'params' hash and via the alias
# 'param'. it can be indexed via string or symbol. the values are all
# Main::Parameter objects
#
foo = params['foo']
#
# the given? method indicates whether or not the parameter was given on
# the commandline/environment, etc. in particular this will not be true
# when a default value was specified but no parameter was given
#
foo.given?
#
# the list of all values can be retrieved via 'values'. note that this
# is always an array.
#
p foo.values
#
# the __first__ value can be retrieved via 'value'. note that this
# never an array.
#
p foo.value
#
# the methods debug|info|warn|error|fatal are delegated to the logger
# object
#
info{ "this goes to the log" }
#
# you can set the exit_status at anytime. this status is used when
# exiting the program. exceptions cause this to be ext_failure if, and
# only if, the current value was exit_success. in otherwords an
# un-caught exception always results in a failing exit_status
#
exit_status exit_failure
#
# a few shortcuts both set the exit_status and exit the program.
#
exit_success!
exit_failure!
exit_warn!
end
}