lite-diff

A simplified text format for describing file changes, inspired by the classic unified diff format.

Specification

📄 Read the full specification → SPEC.md

Overview

lite-diff is designed to be:

• Predictable — position matching by content, not line numbers
• Easy to read — minimal syntax, familiar to anyone who knows unified diff
• Easy to implement — clear rules, well-defined error codes
• AI-friendly — ideal for LLM-generated patches and code editing tools

Quick Example

--- hello.txt
+++ hello.txt
@@
-Hello, World
+Hello, lite-diff

Key Features

Feature	Description
Content-based matching	Finds position by context, ignores line numbers
@@ BOF / @@ EOF	Insert at file beginning or end
Boundary blocks ...	Delete ranges between markers
Global options	--ignore-space-change, --apply-all-matches, etc.
File operations	Create, delete, rename, copy
Comments	Lines starting with # are ignored

File Operations

# Create a new file
--- /dev/null
+++ new-file.txt
@@
+First line
+Second line

# Delete a file
--- old-file.txt
+++ /dev/null

# Rename with modifications
rename from old.txt
rename to new.txt
--- old.txt
+++ new.txt
@@
-old content
+new content

Compatibility

lite-diff accepts standard unified diff headers (diff --git, ---/+++, @@) and extended Git headers. Most patches generated by git diff can be parsed by a lite-diff implementation.

However, lite-diff ignores numeric ranges in hunk headers — it finds positions by matching content, making patches more resilient to minor file changes.

See Interoperability Notes in the specification.

Implementations

• JAI: Diff Editor (lite-diff) — VS Code extension

License

This specification is published under CC BY 4.0.

You are free to share and adapt it with attribution.

Contributing

Found an issue or have a suggestion? Please open an issue.