Keyword Impact Analyzer

A tool to analyze keyword usage across PHP packages to assess the impact of reserving new keywords in PHP.

Built for PHP internals developers and RFC authors to make data-driven decisions about language evolution.

Quick Start

# Download and analyze top 10,000 packages
cargo run --release -- -k let -k using -k scope --max 10000

# Analyze existing downloads
cargo run --release -- -k with --skip-download

Usage

keyword-impact-analyzer [OPTIONS] --keyword <KEYWORD>

Options:
  -k, --keyword <KEYWORD>  Keywords to analyze (repeatable)
  --min <MIN>              Minimum package index [default: 0]
  --max <MAX>              Maximum package index [default: 500]
  -d, --directory <DIR>    Download directory [default: downloads]
  --skip-download          Skip download phase
  -h, --help               Print help

How It Works

1. Download: Fetches top N packages from Packagist
2. Extract: Extracts packages
3. Analyze: Parses PHP files and tracks keyword usage:
   • Soft tracking: Function names, function calls, and closure creations
   • Hard tracking: All identifiers (includes soft + symbol names, metohds, etc.)

Output Format

Results are displayed as a table:

+---------+------+-------+-------------+-------------+-------------------------------------------------------+
| Keyword | Soft | Hard  | Soft Impact | Hard Impact | Well-Known Vendors                                    |
+---------+------+-------+-------------+-------------+-------------------------------------------------------+
| with    |  174 | 36393 | High        | Critical    | doctrine, illuminate, laravel, phpunit, symfony, twig |
+---------+------+-------+-------------+-------------+-------------------------------------------------------+
| scope   |    0 |  3428 | None        | Critical    | laravel, symfony                                      |
+---------+------+-------+-------------+-------------+-------------------------------------------------------+
| block   |    1 |  2476 | Low         | Critical    | doctrine, laravel                                     |
+---------+------+-------+-------------+-------------+-------------------------------------------------------+
| let     |    4 |  1031 | Low         | Critical    | -                                                     |
+---------+------+-------+-------------+-------------+-------------------------------------------------------+
| using   |    0 |   485 | None        | High        | laravel, phpunit                                      |
+---------+------+-------+-------------+-------------+-------------------------------------------------------+
| temp    |    0 |   197 | None        | High        | -                                                     |
+---------+------+-------+-------------+-------------+-------------------------------------------------------+
| scoped  |    2 |    54 | Low         | Medium      | -                                                     |
+---------+------+-------+-------------+-------------+-------------------------------------------------------+

Impact Levels:

• None: 0 occurrences
• Low: 1-25 occurrences
• Medium: 26-100 occurrences
• High: 101-500 occurrences
• Critical: 501+

⚠️ Warning: Analysis of fewer than 200,000 files will show a warning recommending increasing --max for comprehensive results.

Results

Analysis results for various RFCs:

• Opt-in Block Scoping (use construct) - 626,044 files analyzed
  • ✅ Safe: scope, block, let, using, scoped
  • ⚠️ Conflicts: with (174 occurrences)

Contributing

To add analysis for a new RFC:

1. Run the tool with your candidate keywords
2. Create a new file in rfcs/your_rfc_name.md
3. Document the results and add a link in this README

License

This project is distributed under the MIT License. See LICENSE for more information.