vb6semantic 0.1.0

Semantic analysis and symbol table construction for VB6 code
Documentation

vb6semantic

Semantic analysis and symbol table construction for Visual Basic 6 code.

Overview

vb6semantic provides semantic analysis capabilities for VB6 code parsed by vb6parse. It builds symbol tables, performs type checking, resolves names, and validates semantic correctness of VB6 code.

The output of semantic analysis is used by:

  • aspen - for calling out to compile, check, document, and test vb6 code.
  • vb6compile - Before lowering to IR and compilation
  • vb6convert - For conversion analysis and validation
  • vb6interpret - for runtime scope and validation.

Features

  • Symbol Tables: Build comprehensive symbol tables for VB6 projects
  • Scope Management: Hierarchical scope management (global, class, procedure, block)
  • Name Resolution: Resolve symbol references with proper scoping rules
  • Type Checking: Validate type compatibility and assignments
  • Visibility Rules: Enforce Public/Private/Friend visibility rules
  • Error Reporting: Detailed semantic error messages with source locations

Architecture

Core Components

  1. Symbol Table (symbols.rs)

    • Manages symbols across scopes
    • Handles symbol definitions and lookups
    • Tracks symbol metadata

  2. Scope Manager (scope.rs)

    • Hierarchical scope management
    • Parent-child scope relationships
    • Name resolution with scope walking

  3. Type System (types.rs)

    • Type information representation
    • Type compatibility checking
    • Type promotion rules

  4. Semantic Analyzer (analyzer.rs)

    • Main entry point for analysis
    • Coordinates symbol table building
    • Collects errors and warnings

  5. Name Resolver (resolution.rs)

    • Resolves symbol references
    • Handles qualified names
    • Checks accessibility

Symbol Kinds

The following symbol kinds are supported:

  • Variable: Module/local variables
  • Constant: Constant declarations
  • SubProcedure: Sub procedures
  • Function: Functions
  • PropertyGet/Let/Set: Property accessors
  • Class: Class definitions
  • Module: Module files
  • Form: Form files
  • Control: Form controls
  • Enum: Enumeration types
  • EnumMember: Enumeration values
  • UserType: User-defined types
  • TypeMember: Type fields
  • Parameter: Procedure parameters
  • Label: GoTo labels

Scope Hierarchy

Global Scope (Module/Form)
  ├─ Class Scope
  │   ├─ Property Scope
  │   │   └─ Block Scope
  │   └─ Procedure Scope
  │       └─ Block Scope
  └─ Procedure Scope
      └─ Block Scope

Type System

Supported VB6 types:

Primitive Types:

  • Integer, Long, Byte
  • Single, Double, Currency
  • String, Boolean, Date

Complex Types:

  • Variant (universal type)
  • Object (generic object)
  • Class (specific class)
  • UserType (custom type)
  • Enum (enumeration)

Special Types:

  • Nothing, Empty, Null
  • Sub, Function

Type Rules:

  • Variant is compatible with all types
  • Numeric promotions (Byte → Integer → Long → Single → Double)
  • Object-Class relationships

Integration with vb6parse

vb6parse is responsible for loading source files, parsing these source files into the corresponding file types (ProjectFile, ModuleFile, ClassFile, FormFile, etc) and then vb6semantic is responsible for doing semantic analysis on these files.

Module Overview

In addition to the core components listed above, vb6semantic includes:

  • query — Query infrastructure for analyzing projects
  • references — Reference registry and resolvers for manifest/static references

Use Cases

IDE Support

  • Code completion (symbol suggestions)
  • Go to definition
  • Find references
  • Rename refactoring
  • Type information on hover

Static Analysis

  • Find unused variables
  • Detect undefined symbols
  • Check type safety
  • Validate visibility rules
  • Detect dead code

Code Transformation

  • Provide symbol information for converters
  • Enable semantic-aware refactoring
  • Support automated migration

Documentation Generation

  • Extract symbol information
  • Generate API documentation
  • Create cross-references

Implementation Status

✅ Completed

  • Core type system
  • Symbol representation
  • Scope management framework
  • Basic error types
  • Type compatibility checking
  • Reference registry and resolvers
  • Query infrastructure

🚧 In Progress

  • Full VB6 project analysis
  • Complete name resolution across all scope types

📋 Planned

  • Advanced type inference
  • Cross-reference tracking

Examples

Examples are demonstrated through the vb6semantic lib.rs doctests.

Testing

# Run tests
cargo test -p vb6semantic

# Run with output
cargo test -p vb6semantic -- --nocapture

# Test specific module
cargo test -p vb6semantic --lib symbols

Documentation

Contributing

Contributions welcome! Areas that need work:

  • Complete implementation of analysis passes
  • Additional type checking rules
  • Performance improvements
  • More comprehensive tests
  • Better error messages

License

MIT License - see LICENSE for details.

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