[ANN] main-3.0.1

[ara.t.howard]

NAME
main.rb

SYNOPSIS
a class factory and dsl for generating command line programs real quick

URI
http://codeforpeople.com/lib/ruby/
http://rubyforge.org/projects/codeforpeople/
http://github.com/ahoward/main

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
- leather pants

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 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 ptional
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


<========< 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]


<========< 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


<========< 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


<========< samples/e.rb >========>

~ > cat samples/e.rb

require 'main'

ARGV.replace %w( x y argument )

Main {
argument 'argument'
option 'option'

def run() puts 'run' end

mode 'a' do
option 'a-option'
def run() puts 'a-run' end
end

mode 'x' do
option 'x-option'

def run() puts 'x-run' end

mode 'y' do
option 'y-option'

def run() puts 'y-run' end
end
end
}

~ > ruby samples/e.rb

y-run


<========< samples/f.rb >========>

~ > cat samples/f.rb

require 'main'

ARGV.replace %W( compress /data )

Main {
argument('directory'){ description 'the directory to operate on' }

option('force'){ description 'use a bigger hammer' }

def run
puts 'this is how we run when no mode is specified'
end

mode 'compress' do
option('bzip'){ description 'use bzip compression' }

def run
puts 'this is how we run in compress mode'
end
end

mode 'uncompress' do
option('delete-after'){ description 'delete orginal file after
uncompressing' }

def run
puts 'this is how we run in un-compress mode'
end
end
}

~ > ruby samples/f.rb

this is how we run in compress mode


<========< samples/g.rb >========>

~ > cat samples/g.rb

require 'main'

ARGV.replace %w( 42 ) if ARGV.empty?

Main {
argument( 'foo' )
option( 'bar' )

run { puts "This is what to_options produces:
#{params.to_options.inspect}" }
}

~ > ruby samples/g.rb

This is what to_options produces: {"help"=>nil, "foo"=>"42", "bar"=>nil}


<========< samples/h.rb >========>

~ > cat samples/h.rb

require 'main'

# block-defaults are instance_eval'd in the main instance and be
combined with
# mixins
#
# ./h.rb #=> forty-two
# ./h.rb a #=> 42
# ./h.rb b #=> 42.0
#

Main {
fattr :default_for_foobar => 'forty-two'

optionfoobar) do
default{ default_for_foobar }
end

mixin :foo do
fattr :default_for_foobar => 42
end

mixin :bar do
fattr :default_for_foobar => 42.0
end


run{ p params[:foobar].value }

mode :a do
mixin :foo
end

mode :b do
mixin :bar
end
}

~ > ruby samples/h.rb

"forty-two"



DOCS
test/main.rb
vim -p lib/main.rb lib/main/*rb
API section below

HISTORY
3.0.0
- major refactor to support modes via module/extend vs. subclassing.
MIGHT NOT be backward compatible, though no known issues thus far.

2.9.0
- support ruby 1.9

2.8.3
- support for block defaults


2.8.2
- fixes and tests for negative arity/attr arguments, options, eg

argumentfoo){
arity -1
}

def run # ARGV == %w( a b c )
p foo #=> %w( a b c )
end

thanks nathan

2.8.1
- move from attributes.rb to fattr.rb

2.8.0
- added 'to_options' method for Parameter::Table. this allows you
to convert
all the parameters to a simple hash.
for example

Main {
option 'foo'
argument 'baz'

run { puts params.to_options.inspect }

}

2.7.0
- removed bundled arrayfields and attributes. these are now dependancies
mananged by rubygems. a.k.a. you must have rubygems installed for main
to work.

2.6.0
- added 'mixin' feaature for storing, and later evaluating a block of
code. the purpose of this is for use with modes where you want to keep
your code dry, but may not want to define something in the base class
for all to inherit. 'mixin' allows you to define the code to inherit
once and the selectively drop it in child classes (modes) on demand.
for example

Main {
mixin :foobar do
option 'foo'
option 'bar'
end

mode :install do
mixin :foobar
end

mode :uninstall do
mixin :foobar
end

mode :clean do
end
}

- mode definitions are now deferred to the end of the Main block, so you
can do this

Main {
mode 'a' do
mixin :foo
end

mode 'b' do
mixin :foo
end

def inherited_method
42
end

mixin 'foo' do
def another_inherited_method
'forty-two'
end
end
}

- added sanity check at end of paramter contruction

- improved auto usage generation when arity is used with arguments

- removed 'p' shortcut in paramerter dsl because it collided with
Kernel.p. it's now called 'param'. this method is availble *inside* a
parameter definition

option('foo', 'f'){
synopsis "arity = #{ param.arity }"
}

- fixed bug where '--' did not signal the end of parameter parsing in a
getoptlong compliant way

- added (before/after)_parse_parameters, (before/after)_initialize, and
(before/after)_run hooks

- fixed bug where adding to usage via

usage['my_section'] = 'custom message'

totally horked the default auto generated usage message

- updated dependancies in gemspec.rb for attributes (~> 5.0.0) and
arrayfields (~> 4.3.0)

- check that client code defined run, iff not wrap_run! is called. this is
so mains with a mode, but no run defined, still function correctly when
passed a mode

- added new shortcut for creating accessors for parameters. for example

option('foo'){
argument :required
cast :int
attr
}

def run
p foo ### this attr will return the parameter's *value*
end

a block can be passed to specify how to extract the value from the
parameter

argument('foo'){
optional
default 21
cast :int
attr{|param| param.value * 2}
}

def run
p foo #=> 42
end

- fixed bug where 'abort("message")' would print "message" twice on exit
if running under a nested mode (yes again - the fix in 2.4.0 wasn't
complete)

- added a time cast, which uses Time.parse

argument('login_time'){ cast :time }

- added a date cast, which uses Date.parse

argument('login_date'){ cast :date }


2.5.0
- added 'examples', 'samples', and 'api' kewords to main dsl. each
keyword takes a list of strings which will be included in the help
message

Main {
examples "foobar example", "barfoo example"

samples <<-txt
do this

don't do that
txt

api %(
foobar string, hash

barfoo hash, string
)
}

results in a usage message with sections like

...

EXAMPLES
foobar example
barfoo example

SAMPLES
do this

don't do that

API
foobar string, hash

barfoo hash, string

...

2.4.0
- fixed bug where 'abort("message")' would print "message" twice on exit
if running under a nested mode.

- allowed parameters to be overridden completely in subclasses (modes)

2.3.0
- re-worked Main.new such that client code may define an #initialize
methods and the class will continue to work. that is to say it's fine
to do this

Main {
def initialize
@a = 42
end

def run
p @a
end

mode 'foo' do
def run
p @a
end
end
}

the client #initialize will be called *after* main has done it's normal
initialization so things like @argv, @env, and @stdin will all be there
in initialize. of course you could have done this before but you'd have
to both call super and call it with the correct arguments - now you can
simply ignore it.

2.2.0
- added ability for parameter dsl error handlers to accept an argument,
this will be passed the current error. for example

argumentx) do
arity 42

error do |e|
case e
when Parameter::Arity
...
end
end

- refined the mode parsing a bit: modes can now be abbreviated to uniqness
and, when the mode is ambiuous, a nice error message is printed, for
example:

ambiguous mode: in = (inflate or install)?

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 '(e-mail address removed)'
#
# 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:EBUG
#
# 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 ption }
#
# 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 ptional
#
# 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:arameter 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

}


enjoy.