@isl-lang/typechecker

Semantic analyzer for ISL - validates AST, resolves types, and builds symbol tables.

Installation

npm install @isl-lang/typechecker
# or
pnpm add @isl-lang/typechecker

Usage

import { parse } from '@isl-lang/parser';
import { typecheck, TypeChecker } from '@isl-lang/typechecker';

const ast = parse(`
  domain UserManagement {
    type User {
      id: uuid
      name: string
      email: email
    }

    intent CreateUser {
      input { name: string, email: email }
      output { user: User }
    }
  }
`);

// Quick validation
const result = typecheck(ast);

if (result.errors.length > 0) {
  result.errors.forEach(err => console.error(err.message));
} else {
  console.log('Type checking passed!');
  console.log('Symbol table:', result.symbolTable);
}

// Or use the TypeChecker class for more control
const checker = new TypeChecker();
const checked = checker.check(ast);

API

typecheck(ast: AST): TypeCheckResult

Perform type checking on an AST.

Returns:

• errors - Array of type errors found
• warnings - Array of type warnings
• symbolTable - Resolved symbol table
• typeMap - Map of nodes to their resolved types

TypeChecker

Class for incremental type checking with caching.

const checker = new TypeChecker();

// Check multiple files
checker.addFile('user.isl', userAst);
checker.addFile('order.isl', orderAst);

// Get all errors
const errors = checker.getAllErrors();

// Get type for a specific node
const type = checker.getType(node);

Features

• Type inference - Infers types for expressions
• Contract validation - Validates pre/postconditions
• Cross-reference resolution - Resolves type references across domains
• Import validation - Validates imports and exports
• Incremental checking - Efficient re-checking of modified files

Error Types

import { TypeError, TypeErrorCode } from '@isl-lang/typechecker';

// Error codes
TypeErrorCode.UNDEFINED_TYPE
TypeErrorCode.TYPE_MISMATCH
TypeErrorCode.DUPLICATE_DEFINITION
TypeErrorCode.INVALID_CONTRACT

Documentation

Full documentation: https://isl-lang.dev/docs/typechecker

Related Packages

• @isl-lang/parser - ISL parser
• @isl-lang/evaluator - Expression evaluator

License

MIT