JLDiff 1.0.0

Character by character diff script written in Python producing HTML output

JLDiff

Character by character diff script written in Python producing HTML output.

This uses the Longest common subsequence algorithm to do a true character-by-character comparison — no line-by-line preprocessing. The result is HTML with red and green coloring showing exactly what changed.

Note: Larger files take exponentially longer to process due to the nature of the algorithm.

Installation

From PyPI

pip install JLDiff

From GitHub (development version)

# With uv
uv pip install git+https://github.com/JEdward7777/JLDiff.git

# With pip
pip install git+https://github.com/JEdward7777/JLDiff.git

Run as a one-off CLI without installing

# From PyPI
uvx jldiff file1.txt file2.txt out.html

# From GitHub
uv run --from git+https://github.com/JEdward7777/JLDiff.git jldiff file1.txt file2.txt out.html

Usage

Command line

jldiff file1.txt file2.txt out.html [--same_size]

The --same_size flag keeps diff text the same size as surrounding text (by default, changed text is rendered larger for visibility).

As a library

from JLDiff import compute_diff, printDiffs

result = compute_diff("hello world", "hallo world", talk=False)

The compute_diff function takes two strings and returns a list of diff nodes. Each node has a .state (STATE_MATCH, STATE_PASSING_1ST, or STATE_PASSING_2ND) and a .content character. Set talk=False to suppress progress output to stdout.

Use printDiffs(result, output_file) to write the diff as HTML spans to a file-like object.

License

BSD 2-Clause — see LICENSE for details.