Project Brief: Grammar-Modelica Modernization

1. Project Overview

• Repository: albastev/Grammar-Modelica

• Original Scope: A Raku grammar for the Modelica Language Specification 3.4.

• Current Goal: Refactor the grammar to "Modern Raku" (6.d+) to improve parsing efficiency, add comprehensive Action classes for AST generation, and update metadata for the current Raku ecosystem (Zef).

2. Technical Objectives

• Language Standards: Target Modelica 3.6+ (the latest stable specifications) while maintaining backward compatibility where possible.

• Modern Raku Syntax:

• Transition from perl6 to raku file extensions (.rakumod, .t6).

• Update META6.json to the current distribution standard.

• Performance Optimization: * Review backtracking regexes (regex) and convert to non-backtracking token or rule where possible.

• Use proto regexes for keyword-heavy rules (like statement or class-definition) to take advantage of Raku's Longest Token Matching (LTM).

3. Key Features to Implement

A. Full Action Class Implementation

The original repo is primarily the grammar. The modernization will add a robust Action class that:

• Reduces the raw match object into a clean Abstract Syntax Tree (AST).

• Handles Modelica's specific scoping rules (e.g., within clauses and package hierarchies).

B. "Modelica-native" Error Handling

Replace generic parse failures with custom exceptions.

• Implement die or fail calls within the grammar/actions to provide specific line/column information and expected Modelica tokens.

C. Comprehensive Testing Suite

• Migrate to Test::Async or utilize standard Test with modernized subtests.

• Incorporate the Modelica Standard Library (MSL) as a benchmark suite to ensure the grammar can handle real-world, large-scale models.

4. Modernization Checklist

5. Potential Challenges

• Complexity of Expression Rules: Modelica expressions can be deeply nested. Ensuring the grammar doesn't hit recursion limits or performance bottlenecks on large .mo files is a priority.

• Whitespace Handling: Modelica allows for specific comment styles and significant/insignificant whitespace that must be handled carefully using Raku's <.ws> token.

Suggested Directory Structure

Grammar-Modelica/
├── lib/
│   └── Grammar/
│       ├── Modelica.rakumod      # The Grammar
│       └── Modelica/
│           └── Actions.rakumod   # AST Construction
├── t/
│   ├── 01-basic.t                # Sanity checks
│   └── 02-msl-compliance.t       # Tests against MSL
├── resources/                    # Sample .mo files
├── META6.json
└── README.md

6. Getting Started (For Contributors)

To run the modernized grammar locally:

zef install --deps-only .
raku -Ilib -e 'use Grammar::Modelica; say Grammar::Modelica.parsefile("path/to/model.mo")'