Phiki stands out as the strongest modern candidate for replacing WackoWiki's outdated syntax highlighters. It delivers high-quality, server-side rendering using TextMate grammars and VS Code themes, with zero third-party dependencies.

Current WackoWiki Situation

WackoWiki relies on:

• Pear Text_Highlighter — outdated and unmaintained.
• Handcrafted highlighters and the built-in PHP highlighter (limited scope and maintenance).
• GeSHi plugin — also outdated/unmaintained.
• Highlight.js as an optional plugin — excellent language coverage but client-side JavaScript rendering (re-renders on each load, adds JS dependency, and less ideal for static/server-rendered output).

This setup creates maintenance burden, inconsistent quality, and suboptimal performance (especially with client-side JS).

Recommended Primary Replacement: Phiki

Phiki (by Ryan Chandler) is a pure-PHP syntax highlighter inspired by Shiki. It uses TextMate grammar files for accurate tokenization and VS Code themes for styling.

Key strengths:

• High-quality highlighting — Matches VS Code/editor accuracy for many languages.
• Server-side only — Generates static HTML once (no repeated client-side work).
• Fast and lightweight — Pure PHP, no Node.js or heavy deps.
• Themes — Supports popular VS Code themes (e.g., GitHub Light/Dark).
• Extensible — Transformers for custom features (line numbers, highlighting, etc.).
• Actively maintained — Recent releases (v2.x as of 2026), good documentation at phiki.dev.

Basic usage (Composer install: composer require phiki/phiki:^2.0):

use Phiki\Phiki;
use Phiki\Grammar\Grammar;
use Phiki\Theme\Theme;

$phiki = new Phiki();
$code = 'your code here...';

$highlighted = $phiki->codeToHtml($code, Grammar::Php, Theme::GithubLight);
echo $highlighted;  // Ready-to-use HTML

It also supports terminal output and various grammars/themes.

Integration into WackoWiki:

• Create a new formatter (e.g., phiki.php in the formatters directory).
• Hook it into the %%(language) code %% syntax (Wacko already supports language specifiers).
• Map common language names to Phiki's Grammar::* constants.
• Add configuration for default theme, line numbers, etc.
• Cache highlighted output (Wacko already does some caching; enhance for code blocks).
• Provide a fallback for unsupported languages.

Pros for Wacko:

• Replaces multiple outdated systems with one modern library.
• Consistent, beautiful output that matches modern editors.
• Better performance than JS-based solutions for page loads.
• Easy to extend with Wacko-specific features (e.g., copy button, line highlighting).

Potential cons:

• Language support depends on included TextMate grammars (strong for popular languages; may need additions for obscure ones).
• Initial integration effort (but far less than maintaining old highlighters).

Strong Alternative: Tempest Highlight

Another excellent modern PHP option is Tempest Highlight (tempest/highlight).

• Very fast, extensible, server-side.
• Good for common languages (PHP, HTML, CSS, Blade, etc.).
• Easy API and custom language support.
• Actively developed and used in real projects.

It could serve as a lighter alternative or complement if Phiki's grammar approach feels heavy for some use cases.

Other Options

• Keep/enhance Highlight.js — As a progressive enhancement or for rare languages. Load it lazily or only when Phiki doesn't support a language. This gives the best of both (server for most, client for edge cases).
• Pygments — Excellent Python library with massive language support, but requires a bridge (e.g., exec or microservice), adding complexity and a Python dependency. Not ideal for pure-PHP Wacko.
• Shiki (via shiki-php) — Similar quality to Phiki but spawns Node.js (slower for live rendering).
• Prism.js or updated highlight.php — Client- or older server-side; generally inferior to Phiki/Tempest now.

Implementation Roadmap Suggestion

1. Evaluate — Test Phiki + Tempest on Wacko sample pages with various languages.
2. Core Integration — Build a PhikiFormatter (or make it configurable between Phiki/Tempest).
3. Backward Compatibility — Alias old formatters or migrate gradually.
4. Configuration — Admin settings for default theme, enabled languages, line numbers.
5. Enhancements — Add common features: copy-to-clipboard, line numbers, diff highlighting, language auto-detect (fallback).
6. Performance — Benchmark render times and implement caching for code blocks.
7. Plugins — Optional full Highlight.js fallback or additional themes.
8. Documentation & Testing — Update Wacko docs and test with real user content.

Phiki is the clear frontrunner: modern, high-quality, pure PHP, and designed exactly for this use case. It would significantly modernize WackoWiki's code presentation and reduce long-term maintenance.

If you share more details (e.g., target Wacko version, priority languages, or specific requirements like line numbers), I can help refine the integration approach or suggest code snippets.