cute_print

Write debug output to stderr. Optionally print the source filename and line number, or the source of the debug statement. Easily inspect the middle of a call chain.

Installation

Add this line to your application's Gemfile:

gem "cute_print"

And then execute:

$ bundle

Or install it yourself:

$ gem install cute_print

Usage

Start with:

require "cute_print"

q work like Kernel#p, except that it prints to $stderr instead of $stdout.

q "abc"            # "abc"
q [1, 2, 3 + 4]    # [1, 2, 7]

By passing a block, you can have the debug source printed along with the value:

i = 1
q {i + 2}         # i + 2 is 3

ql will also print the source location:

ql "abc"        # foo.rb:12: "abc"
ql {1 + 2}      # foo.rb:13: 1 + 2 is 3

When called with no arguments, ql just prints the source location:

ql              # foo.rb:14

This is very handy for answering "which branch did it take?," or "did it even get to that method?"

qq pretty-prints its arguments to $stderr:

a = (1..30).to_a
qq a            # [1,
                #  2,
                #  ...
                #  20,
                #  30]

qql also prints the source location:

a = (1..30).to_a
qq a            # foo.rb:12: [1,
                #            2,
                #            ...
                #            20,
                #            30]

tapq inspects the middle of a call chain:

["1", "2"].map(&:to_i).tapq.inject(&:+)
# [1, 2]

tapql also prints the source location:

["1", "2"].map(&:to_i).tapql.inject(&:+)
# bar.rb:12: [1, 2]

tapqq pretty-prints the middle of a call chain:

a = (1..30).to_a
sum = a.tapqq.inject(:+)    # [1,
                            # 2,
                            # ...
                            # 20,
                            # 30]

tapqql also prints the source location:

a = (1..30).to_a
sum = a.tapqq.inject(:+)    # foo.rb:12: [1,
                            #             2,
                            #             ...
                            #             20,
                            #             30]

Configuration

To change the output device:

CutePrint.configure do |c|
  c.out = File.open('/tmp/debug')
end

Any object that responds to #print will do.

To cause #ql, #qql and #tapql to print the full path rather than just the filename:

CutePrint.configure do |c|
  c.location_format = :path
end

To reset the configuration to its defaults:

CutePrint.configure do |c|
  c.reset
end

Rubies supported

This gem is known to work with these Rubies:

ruby-1.9.3
ruby-2.0.0
ruby-2.1.2

Platforms supported

This gem is developed and tested with Linux. It should work on Windows and OSX as well. If it does not work for you, please file an issue on github.

Other gems with similar functions

The wrong gem includes the excellent #d method, which is very much like this gem's #q method. This gem's ability to read the debug statement's source is derived from the wrong gem.

Versioning

This gem uses semantic versioning 2.0.

While the version is < 1.0.0, the API can change with any version increment. If you need stability, lock the gem down to a minor version, e.g.:

gem "cute_print", "~> 0.1.0"

Contributing

Fork it ( http://github.com/wconrad/cute_print/fork )
Create your feature branch (git checkout -b my-new-feature)
Commit your changes (git commit -am 'Add some feature')
Push to the branch (git push origin my-new-feature)
Create new Pull Request