simple_eiffel_parser

Documentation | GitHub

Lightweight Eiffel source code parser for extracting structural information. Designed for IDE tooling, code analysis, and documentation generation.

Part of the Simple Eiffel ecosystem.

Developed using AI-assisted methodology: Built interactively with Claude Opus 4.5 following rigorous Design by Contract principles.

Overview

simple_eiffel_parser is a recursive descent parser that extracts structural information from Eiffel source code without performing full semantic analysis. It is optimized for speed and IDE use cases rather than compilation.

What it extracts:

• Class declarations (deferred, expanded, frozen)
• Feature signatures with types
• Arguments and local variables
• Preconditions and postconditions
• Inheritance relationships (rename, redefine, undefine, select)
• Header comments for documentation

What it does not do:

• Type checking or inference
• Semantic analysis
• Full expression parsing
• SCOOP semantics validation

Quick Start

local
    parser: SIMPLE_EIFFEL_PARSER
    ast: EIFFEL_AST
do
    create parser.make
    ast := parser.parse_file ("my_class.e")

    across ast.classes as c loop
        print ("Class: " + c.name + "%N")
        across c.features as f loop
            print ("  Feature: " + f.name + "%N")
        end
    end
end

Architecture

• simple_eiffel_parser.e - Facade class (107 lines)
• eiffel_parser.e - Recursive descent parser (871 lines)
• eiffel_lexer.e - Tokenizer (436 lines)
• eiffel_token.e - Token definitions (160 lines)
• Plus AST node classes for classes, features, arguments, locals, parents, errors

Total: 2,327 lines of Eiffel code across 11 classes.

Dependencies

• simple_file - File reading
• simple_regex - Pattern matching

Building

export SIMPLE_EIFFEL_PARSER=/path/to/simple_eiffel_parser
export SIMPLE_FILE=/path/to/simple_file
export SIMPLE_REGEX=/path/to/simple_regex

ec.exe -batch -config simple_eiffel_parser.ecf -target simple_eiffel_parser_tests -c_compile
./EIFGENs/simple_eiffel_parser_tests/W_code/simple_eiffel_parser.exe

Use Cases

The primary consumer is simple_lsp, the Eiffel LSP server. The parser provides symbol information for go-to-definition, hover documentation, code completion, and document outline.

Roadmap

Feature	Status
Basic parsing	Complete
Contract extraction	Complete
Error recovery	Complete
Comment preservation	Complete
Generic parsing	Complete
ECF parsing	Planned
Type resolution	Planned

License

MIT License

Resources

• Simple Eiffel Organization
• simple_lsp
• Eiffel Language