symtable.js

An imperative symbol table library in Javascript

Installation

Requires ES6.

npm install symtable.js

Usage

var Symtable = require('symtable.js');

var globalIds = new Map();
globalIds.set('window', 1);
globalIds.set('document', 2);

// Initialize a new symbol table with a map of symbols in the global scope.
var S = new Symtable(globalIds);

// Start a new nested scope
S.enterScope();

// Add a symbol to the table
S.add('a', '3');
S.add('b', 4);

// Find the value of a Symbol
S.find('a'); // 3
S.find('k'); // null

// Check the current scope for a given symbol
S.checkScope('a'); // true
S.checkScope('window'); // false. Since this exists in the global scope and the current scope.

// Exit the current scope
S.exitScope();

API

• enterScope() - Start a new nested scope.

• add(x, y) - Add a new symbol x with associated data y.

• find(x) - Finds current x in the whole symbol table using the most closely nested rule. Returns null otherwise.

• checkScope(x) - Returns true if x is defined in the current scope.

• exitScope() - Exit the current scope