Class: DynamicLocals::EvalTranslator

Inherits:
BaseTranslator show all
Defined in:
lib/dynamic_locals/eval_translator.rb

Overview

This is (probably) the simplest possible implementation of the behaviour we want. It builds a new string of Ruby code with assignments to the locals each time it is called and evals that string.

This is not intended to be used in production code, but for debugging and as a reference implementation.

Instance Attribute Summary

Attributes inherited from BaseTranslator

#known_locals, #locals_hash, #lookup_strategy, #original_src

Instance Method Summary collapse

Methods inherited from BaseTranslator

#initialize, #parameters, #to_s

Constructor Details

This class inherits a constructor from DynamicLocals::BaseTranslator

Instance Method Details

#translate ⇒ Object 



11
12
13
14
15
16
17
18
19
20
 
# File 'lib/dynamic_locals/eval_translator.rb', line 11

def translate
  # `eval` compiles its argument as a standalone program, which -- unlike a
  # method body -- has no implicit `begin`. Wrap the source in begin/end so a
  # method-body-style implicit rescue parses.
  body = "begin\n#{original_src}\nend"
  # The file/line arguments make errors report the line the source would
  # occupy had it been spliced in directly: the `begin` line lands one
  # line above the eval call, so source line N reports as call line + N.
  %{eval(#{locals_hash}.keys.map { |k| "\#{k} = #{locals_hash}[\#{k.inspect}];" }.join + #{body.inspect}, binding, __FILE__, __LINE__ - 1)}
end