From: eregontp@...
Date: 2019-11-27T17:42:12+00:00
Subject: [ruby-dev:50868] [Ruby master Feature#16142] Implement code_range	in Proc and Method

Issue #16142 has been updated by Eregon (Benoit Daloze).


Maybe we could change #source_location to return a `SourceLocation` and have `SourceLocation#to_a` so `file, line = proc.source_location` would still work?

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Feature #16142: Implement code_range in Proc and Method
https://bugs.ruby-lang.org/issues/16142#change-82831

* Author: okuramasafumi (Masafumi OKURA)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
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# Abstract

Add a new method `code_range` as an alternative to `source_location` to Proc and Method

# Background

I'd like to get a body from a Proc in TraceLocation gem (https://github.com/yhirano55/trace_location), in order to add what's executed to the output. There's no way to do that in current Ruby implementation, so as an alternative, I considered getting source code location of a Proc.

# Proposal

I propose that `Proc#code_range` and `Method#code_range`. Other names can work as well, for example `Proc#source_region`. It returns an array containing filename as a first argument and position information as a second array. For example:
`a_proc.position # => [(irb), [1, 5, 3, 25]]`

# Implementation

I've implemented a simpler version of this, see gist for more details.

https://gist.github.com/okuramasafumi/ac90bbf04a1c13b7d67954c9c5e62553

Notice I use `code_location` from iseq struct.

# Discussion

One might say that we can simply add columns and end position to Proc#source_location. However, this can easily brake existing apps such as Pry.
It's also possible that we add additional keyword argument to `Proc#source_location`, for instance:
`a_proc.source_location(including_range: true)`
This change can also break existing apps since in old Rubies this keyword argument cannot be accepted.
Therefore, adding a new method is better in terms of backward compatibility. It might be better at readability as well.

# Summary

I propose an API to get code position of Proc and Method so that we can get body of them (especially of a Proc).



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