Reflection/Get source
The goal is to get the source code or file path and line number where a programming object (e.g. module, class, function, method) is defined.
You are encouraged to solve this task according to the task description, using any language you may know.
- Task
JavaScript
Function.toString() will return the source code for user-defined functions.
<lang javascript>function foo() {...} foo.toString(); // "function foo() {...}" </lang>
For native functions, the function body typically will be a syntactically invalid string indicating the function is native. This behavior isn't part of any ECMAScript standard, but is common practice. <lang javascript>Math.sqrt.toString(); // "function sqrt() { [native code] }" </lang>
Python
Modules loaded from files have a __file__ attribute.
<lang python>import os
os.__file__
- "/usr/local/lib/python3.5/os.pyc"
</lang>
Ruby
Method#source_location will return the file and line number of a Ruby method. If a method wasn't defined in Ruby, Method#source_location returns nil.
<lang ruby>require 'mathn'
Math.method(:sqrt).source_location
- ["/usr/local/lib/ruby2.3/2.3.0/mathn.rb", 119]
Class.method(:nesting).source_location
- nil, since Class#nesting is native
</lang>