Class: RubyTransform::Transformers::BlockMethodToProcifier

Inherits:
RubyTransform::Transformer show all
Defined in:
lib/ruby_transform/transformers/block_method_to_procifier.rb

Overview

Block Method To Proc Transform

Looks for cases where we’re calling a single method on a single-parameter block argument. These instances can use the Ruby 1.9 and ActiveSupport “Symbol#to_proc” trick.

Example:

collection.map {|d| d.name }

Transforms To:

collect.map(&:name)

Instance Method Summary collapse

Methods included from RubyTransform::TransformerHelpers

#sexp?

Instance Method Details

#matches_block_to_use_tap?(e) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ruby_transform/transformers/block_method_to_procifier.rb', line 29

def matches_block_to_use_tap?(e)
  e.kind == :iter &&  # Calls block
  e.body[2] && e.body[2].kind == :call &&  # Body of block is a simple method call
  e.body[2] && e.body[2].body[0] && e.body[2].body[0].kind == :lvar &&  # Simple method call is on a local variable
  e.body[1] && e.body[1].kind == :lasgn &&  # Block parameter is a single assign
  e.body[2] && e.body[2].body[0].body[0] == e.body[1].body[0]  # Local variable is identical to the first block argument
end

#transform(e) ⇒ Object 



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# File 'lib/ruby_transform/transformers/block_method_to_procifier.rb', line 17

def transform(e)
  super transform_block_methods_to_proc(e)
end

#transform_block_methods_to_proc(e) ⇒ Object 



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# File 'lib/ruby_transform/transformers/block_method_to_procifier.rb', line 21

def transform_block_methods_to_proc(e)
  if sexp?(e) && matches_block_to_use_tap?(e)
    transform_block_to_use_tap(e)
  else
    e
  end
end

#transform_block_to_use_tap(e) ⇒ Object 



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# File 'lib/ruby_transform/transformers/block_method_to_procifier.rb', line 37

def transform_block_to_use_tap(e)
  s(:call, 
    e.body[0].body[0], 
    e.body[0].body[1], 
    s(:arglist, s(:block_pass, s(:lit, e.body[2].body[1])))
  )
end