simple_eiffel_parser - Eiffel Source Code Parser

Overview

simple_eiffel_parser is a recursive descent parser that extracts structural information from Eiffel source code. It's designed for IDE tooling, code analysis, and documentation generation - not compilation.

Built as a dependency for simple_lsp, this parser provides the symbol extraction needed for hover documentation, go-to-definition, code completion, and document outline features.

What It Extracts

Class Declarations

Deferred, expanded, frozen classes with header comments.

Feature Signatures

Arguments, return types, and export status for all features.

Contracts

Preconditions (require) and postconditions (ensure) as text.

Inheritance

Parent classes with rename, redefine, undefine, and select clauses.

Local Variables

Local variable declarations with types and line numbers.

Error Recovery

Continues parsing after errors, returns partial results.

API Design

simple_eiffel_parser follows Design by Contract principles:

parse_file

parse_file (a_path: STRING): EIFFEL_AST

Parse an Eiffel source file and return the abstract syntax tree.

Contracts

require: a_path /= Void and then not a_path.is_empty

ensure: Result /= Void

parse_string

parse_string (a_source: STRING): EIFFEL_AST

Parse Eiffel source code from a string.

Contracts

require: a_source /= Void

ensure: Result /= Void

Architecture

The parser consists of 11 classes totaling 2,327 lines of Eiffel code:

Class	Lines	Purpose
SIMPLE_EIFFEL_PARSER	107	Facade class
EIFFEL_PARSER	871	Recursive descent parser
EIFFEL_LEXER	436	Tokenizer
EIFFEL_TOKEN	160	Token definitions
EIFFEL_CLASS_NODE	155	Class representation
EIFFEL_FEATURE_NODE	265	Feature representation
EIFFEL_PARENT_NODE	88	Inheritance representation
EIFFEL_AST	64	AST container
EIFFEL_ARGUMENT_NODE	47	Argument representation
EIFFEL_LOCAL_NODE	47	Local variable representation
EIFFEL_PARSE_ERROR	87	Error representation

Building from Source

Prerequisites

EiffelStudio 25.02+
simple_file library
simple_regex library

Build Commands

# Set environment variables
export SIMPLE_EIFFEL_PARSER=/path/to/simple_eiffel_parser
export SIMPLE_FILE=/path/to/simple_file
export SIMPLE_REGEX=/path/to/simple_regex

# Compile and run tests
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