Create the side-by-side option (-y) feature for the diff command (Incomplete)

[sami-daniel]

• Create the function, in the utils package, limited_string that allows you to truncate a string based on a delimiter (May break the encoding of the character where it was cut)

• Create tests for limited_string function

• Add support for -y and --side-by-side flags that enables diff output for side-by-side mode

• Create implementation of the diff -y (SideBySide) command, base command for sdiff, using the crate diff as engine. Currently it does not fully represent GNU diff -y, some flags (|, (, ), , /) could not be developed due to the limitation of the engine we currently use (crate diff), which did not allow perform logic around it. Only the use of '<' and '>' were enabled.

TL;DR

A new limited_string function was added to the utils package, allowing strings to be truncated based on a delimiter (note: this may break character encoding at the cut point). Unit tests were created to ensure correct behavior of the function.

Support for the -y and --side-by-side flags was added to enable side-by-side diff output. The SideBySide implementation, serving as the base for the sdiff command, was developed using the diff crate as the comparison engine. Due to limitations of the crate, only the < and > markers are currently supported—other markers like |, (, ),\ and / could not be implemented.

Clarification
The main goal of the limited_string function is to simplify and standardize the process of truncating strings for everyone working on the project. The idea was to provide a utility that anyone could use without having to reimplement or worry too much about string manipulation logic. However, a known limitation of the current implementation is that it can break character encoding, especially when the cut happens mid-way through a multi-byte character (e.g., in UTF-8).

I am open to suggestions on how to improve or safely handle encoding, whether by detecting boundaries or using a safer string-splitting strategy that respects character integrity.

Regarding the SideBySide implementation: I recognize that the output and edit script provided by the diff crate is limited. These limitations currently prevent us from supporting additional characters such as |, (, ), , or / that are used in GNU diff -y to more accurately reflect changes in lines.

For this initial version, I think the use of < and >, are sufficient for a first pass of side-by-side comparison. Moving forward, I did like to open a follow-up issue where we can evaluate better strategies (possibly even considering another diff engine) to handle richer diff representations and support for the missing symbols.

Suggestions and ideas are very welcome!

[codecov]

Codecov Report

Attention: Patch coverage is 39.83740% with 74 lines in your changes missing coverage. Please review.

Project coverage is 83.68%. Comparing base (c02273c) to head (1374279).

Files with missing lines	Patch %	Lines
src/side_diff.rs	0.00%	68 Missing ⚠️
src/params.rs	28.57%	5 Missing ⚠️
src/diff.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #117      +/-   ##
==========================================
- Coverage   84.66%   83.68%   -0.99%     
==========================================
  Files          12       13       +1     
  Lines        5627     5748     +121     
  Branches      476      479       +3     
==========================================
+ Hits         4764     4810      +46     
- Misses        848      921      +73     
- Partials       15       17       +2     

Flag	Coverage Δ
macos_latest	83.71% <39.83%> (-0.95%)	⬇️
ubuntu_latest	83.81% <39.83%> (-0.96%)	⬇️
windows_latest	22.98% <1.62%> (-0.49%)	⬇️

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[sami-daniel]

I'll fix the alerts before reopening the PR, 😁

[sami-daniel]

Is done : )

[oSoMoN]

Hi Sami. Thanks for your work on this feature!
I don't have time to spare right now to review it, but please be assured that I will as soon as I can.

[Copilot]

Pull Request Overview

This PR introduces a new string truncation utility (limited_string) with unit tests, and implements a side-by-side diff mode using the diff crate for output.

• Added limited_string utility in the utils package with tests
• Implemented the -y/--side-by-side flags and corresponding diff output in side_diff
• Updated module re-exports and parameter parsing to support the new feature

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/utils.rs	Added limited_string function and tests
src/side_diff.rs	Implemented side-by-side diff output using diff crate
src/params.rs	Added parameter handling for -y/--side-by-side flag
src/main.rs	Integrated side_diff module into main diff workflow
src/lib.rs	Re-exported side_diff diff function with an alias
src/diff.rs	Updated to include the new side_diff option

Comments suppressed due to low confidence (2)

src/side_diff.rs:22

• There are multiple spelling issues: 'nescessary' should be 'necessary' and 'lenght' should be 'length'; please correct these in the comment.

    // recalculate how many spaces are nescessary, cause we need to take into consideration the lenght of the word before print it.

src/lib.rs:15

• [nitpick] The re-export alias 'side_by_syde_diff' appears to have a typo; consider renaming it to 'side_by_side_diff' for clarity.

pub use side_diff::diff as side_by_syde_diff;