# \[ANN\] Initial release of the desc\_method gem--a "run time RI for methods" **URL:** \ **Category:** Ruby\ **Created:** [August 18, 2009, 6:07pm UTC](https://www.ruby-forum.com/t/ann-initial-release-of-the-desc-method-gem-a-run-time-ri-for-methods/173956 "2009-08-18T18:07:40Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![rogerdpack](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/45deac/32.png) [@rogerdpack](https://www.ruby-forum.com/u/rogerdpack)\ **Post date:** [August 18, 2009, 6:07pm UTC](https://www.ruby-forum.com/t/ann-initial-release-of-the-desc-method-gem-a-run-time-ri-for-methods/173956/1 "2009-08-18T18:07:40Z")
I am pleased to announce the release of desc\_method. A “run time RI for methods”, this gem allows you to query for information about objects’ methods within irb or a ruby-debug prompt. It reveals everything known about the method. This includes source, ri, arity, rdoc comments (on 1.9), etc. where available For me it has proved quite useful, and I wouldn’t do a ruby-debug session without it–try it–you might really like it. Examples: > > class A; > > def go(a); end; > > end > > A.desc\_method :go > > #\ arity: 1 > > ri for A#go > > Nothing known about A > > (end ri) > > def go(a) # do nothing end Parameters: go(a) > > File.desc\_method :delete > > ri for File.delete > > ----------------------------------------------------------- File::delete > > File.delete(file\_name, …) =\> integer > > File.unlink(file\_name, …) =\> integer ``` From Ruby 1.9.1 ``` * * * ``` Deletes the named files, returning the number of names passed as arguments. Raises an exception on any error. See also +Dir::rmdir+. ``` (end ri) #\ arity: -1 appears to be a c method #parameters signature: delete( [[:rest]] ) Or (my favorite) using it in a debug session: (rdb:1) l= … =\> 74 assert(assigns[‘order’].order\_line\_items.map(:unit\_price).min \>= -5) … (rdb:1) desc\_method :assert #\ arity: -2 ri for Test::Unit::Assertions#assert ------------------------------------------ Test::Unit::Assertions#assert assert(boolean, message=nil) ``` From gem test-unit-2.0.1 ``` * * * ``` Asserts that +boolean+ is not false or nil. Example: assert [1, 2].include?(5) ``` (end ri) def assert(boolean, message = nil) \_wrap\_assertion do assert\_block(“assert should not be called with a block.”) do (not block\_given?) end assert\_block(build\_message(message, “\ is not true.”, boolean)) { boolean } end end Parameters: assert(boolean, message = nil) (rdb:1) ========= How to Install===== $ gem install rogerdpack-desc\_method or $ gem install rogerdpack-desc\_method --source [http://gems.github.com](http://gems.github.com) if you don’t have [gems.github.com](http://gems.github.com) as a gem source. Usage: > > require ‘desc\_method’ > > Class.desc\_method :method\_name # class or instance method name > > … > > some\_object.desc\_method :method\_name > > … Other goodies also included: Class#desc\_class Examples: > > Object.desc\_class # outputs descriptive info about that class–RI, method list, etc. > > Object.desc\_class :verbose =\> true # outputs RI, method lists including inherited methods, ancestors, all constants etc. Kernel#methods This has been monkey patched to output a “separator” between its inherited and non inherited methods–i.e. > > instance.methods > > =\> [:first, :second, :after\_this\_are\_inherited\>\>\>\>\>, > > :some\_inherited\_method, :another\_inherited\_method] # adds in that > > separator Though I’ll probably remove that in a future release since it turns out you can just run Kernel#methods(false) for about as much usefulness. === Thanks === This gem wraps for convenience the functionality of Method#source\_location, ruby2ruby, et al, and also contains some code inspiration from manvenu, SourceRef (MBARI), and Python’s Method#desc. It also wouldn’t be useful without irb and the ruby-debug folks. Thanks! Comments/suggestions welcome rogerdpack on gmail or github ---
**Author:** ![rogerdpack](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/45deac/32.png) [@rogerdpack](https://www.ruby-forum.com/u/rogerdpack)\ **Post date:** [August 18, 2009, 6:21pm UTC](https://www.ruby-forum.com/t/ann-initial-release-of-the-desc-method-gem-a-run-time-ri-for-methods/173956/2 "2009-08-18T18:21:44Z")
hm, is that just me, or why am i getting this strange error? ERROR: Error installing rogerdpack-desc\_method: ruby2ruby requires ruby\_parser (~\> 2.0, runtime) never had that before… Other stuff seems to install just fine. ---
**Author:** ![rogerdpack](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/45deac/32.png) [@rogerdpack](https://www.ruby-forum.com/u/rogerdpack)\ **Post date:** [August 19, 2009, 12:10am UTC](https://www.ruby-forum.com/t/ann-initial-release-of-the-desc-method-gem-a-run-time-ri-for-methods/173956/3 "2009-08-19T00:10:40Z")
On Aug 18, 1:20 pm, Fabian S. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > [Note: parts of this message were removed to make it a legal post.] > > hm, is that just me, or why am i getting this strange error? > > ERROR: Error installing rogerdpack-desc\_method: > ruby2ruby requires ruby\_parser (~\> 2.0, runtime) > > never had that before… Installing gems from GitHub that depends on gems from RubyForge (ala: cross source dependencies) hasn’t been implemented in RubyGems Patches are welcome 😉 Cheers, ---
**Author:** ![rogerdpack](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/45deac/32.png) [@rogerdpack](https://www.ruby-forum.com/u/rogerdpack)\ **Post date:** [August 18, 2009, 6:58pm UTC](https://www.ruby-forum.com/t/ann-initial-release-of-the-desc-method-gem-a-run-time-ri-for-methods/173956/4 "2009-08-18T18:58:37Z")
> ERROR: Error installing rogerdpack-desc\_method: > ruby2ruby requires ruby\_parser (~\> 2.0, runtime) > > never had that before… > Other stuff seems to install just fine. Yes I get that too, for some reason. Very weird. The work-around for now is $ gem install ruby\_parser $ gem install ruby2ruby -v1.1.9 $ gem install rogerdpack-desc\_method until I can figure out what’s going on. Thanks! -r