A debugging tool.
The gem allows to trace local variables and memory usage for Ruby code.
It's intended for use in a development environment only.
Blab is inspired by PySnooper.
Put this line in your Gemfile
gem "blab", group: :developmentThen run
bundle install
Use the blab decorator in front of a method defenition.
require "blab"
class Test
blab def longest_rep(str)
max = str.chars.chunk(&:itself).map(&:last).max_by(&:size)
max ? [max[0], max.size] : ["", 0]
end
end
Test.new.longest_rep("cbaaabb")The output to STDOUT:
Var......... str="cbaaabb"
18:17:26.042 call test/support/test.rb:46 blab def longest_rep(str)
18:17:26.042 line test/support/test.rb:47 max = str.chars.chunk(&:itself).map(&:last).max_by(&:size)
Var......... max=["a", "a", "a"]
18:17:26.043 line test/support/test.rb:48 max ? [max[0], max.size] : ["", 0]
18:17:26.043 return test/support/test.rb:49 end
The gem allows to wrap only a piece of code in a block:
class Test
def shuffle(arr)
for n in 0...arr.size
targ = n + rand(arr.size - n)
arr[n], arr[targ] = arr[targ], arr[n] if n != targ
end
end
def pairs(a, b)
with_blab do
a << "Insane"
shuffle(b)
end
b.each { |x| shuffle(a); a.each { |y| print y, " ", x, ".\n" } }
end
end
Test.new.pairs(["Bored", "Curious"], ["cat", "frog"])The output:
Var......... a=["Bored", "Curious"]
Var......... b=["cat", "frog"]
18:38:15.188 line test/support/test.rb:54 a << "Insane"
18:38:15.188 line test/support/test.rb:55 shuffle(b)
Var......... arr=["cat", "frog"]
18:38:15.188 call test/support/test.rb:45 def shuffle(arr)
18:38:15.189 line test/support/test.rb:46 for n in 0...arr.size
Var......... n=0
18:38:15.189 line test/support/test.rb:47 targ = n + rand(arr.size - n)
Var......... targ=0
18:38:15.189 line test/support/test.rb:48 arr[n], arr[targ] = arr[targ], arr[n] if n != targ
Var......... n=1
18:38:15.189 line test/support/test.rb:47 targ = n + rand(arr.size - n)
Var......... targ=1
18:38:15.189 line test/support/test.rb:48 arr[n], arr[targ] = arr[targ], arr[n] if n != targ
18:38:15.189 return test/support/test.rb:50 end
Output to a file:
Blab::Config.log_output = "log/blab.log"Datetime format:
Blab::Config.datetime_format = "%H:%M:%S.%L"Custom logger:
Blab::Config.logger = MyCustomLogger.newTrace C calls your program makes from Ruby:
Blab::Config.trace_c_calls = trueTrace only within the original scope.
It means that the trace will be showed only for the current method and it will skip all external call's traces.
Blab::Config.original_scope_only = trueFormat output. Available config is:
output_order = [
{ type: :time, order: 1, width: 12 },
{ type: :event, order: 2, width: 6 },
{ type: :file_lines, order: 3, width: 30 },
{ type: :class_name, order: 4, width: 10 },
{ type: :method_name, order: 5, width: 12 },
{ type: :code_lines, order: 7, width: 120 }
]
Blab::Config.output_order = output_orderBy default it doesn't show current class name and method name. You can adjust the width, change the order, skip/add the desired output info.
Fork & Pull Request.
Run the tests via rake.
MIT