js-slang
Version:
Javascript-based implementations of Source, written in Typescript
97 lines • 4.18 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.defineVariable = exports.currentEnvironment = exports.declareIdentifier = exports.handleRuntimeError = exports.getDeclaredNames = exports.isAllowedLiterals = exports.isNumber = exports.isNegNumber = exports.isPositiveNumber = exports.isInfinity = exports.isImportedFunction = exports.isBuiltinFunction = exports.prettyPrintError = void 0;
const errors = require("../errors/errors");
const builtin = require("./lib");
function prettyPrintError(error) {
return `Line ${error.location.start.line}: ${error.explain()}`;
}
exports.prettyPrintError = prettyPrintError;
function isBuiltinFunction(node) {
return (node.type === 'Identifier' &&
// predeclared, except for evaluateMath
((typeof builtin[node.name] === 'function' && node.name !== 'evaluateMath') ||
// one of the math functions
Object.getOwnPropertyNames(Math)
.filter(name => typeof Math[name] === 'function')
.map(name => 'math_' + name)
.includes(node.name)));
}
exports.isBuiltinFunction = isBuiltinFunction;
function isImportedFunction(node, context) {
return (node.type === 'Identifier' &&
Object.keys(context.runtime.environments[0].head).includes(node.name));
}
exports.isImportedFunction = isImportedFunction;
function isInfinity(node) {
return node.type === 'Identifier' && node.name === 'Infinity';
}
exports.isInfinity = isInfinity;
function isPositiveNumber(node) {
return node.type === 'Literal' && typeof node.value === 'number';
}
exports.isPositiveNumber = isPositiveNumber;
function isNegNumber(node) {
return (node.type === 'UnaryExpression' &&
node.operator === '-' &&
(isInfinity(node.argument) || isPositiveNumber(node.argument)));
}
exports.isNegNumber = isNegNumber;
function isNumber(node) {
return isPositiveNumber(node) || isNegNumber(node);
}
exports.isNumber = isNumber;
function isAllowedLiterals(node) {
return node.type === 'Identifier' && ['NaN', 'Infinity', 'undefined'].includes(node.name);
}
exports.isAllowedLiterals = isAllowedLiterals;
function getDeclaredNames(node) {
const declaredNames = new Set();
for (const stmt of node.body) {
// if stmt is assignment or functionDeclaration
// add stmt into a set of identifiers
// return that set
if (stmt.type === 'VariableDeclaration') {
stmt.declarations
.map(decn => decn.id)
.map(id => id.name)
.forEach(name => declaredNames.add(name));
}
else if (stmt.type === 'FunctionDeclaration' && stmt.id) {
declaredNames.add(stmt.id.name);
}
}
return declaredNames;
}
exports.getDeclaredNames = getDeclaredNames;
const handleRuntimeError = (context, error) => {
context.errors.push(error);
throw error;
};
exports.handleRuntimeError = handleRuntimeError;
const DECLARED_BUT_NOT_YET_ASSIGNED = Symbol('Used to implement hoisting');
function declareIdentifier(context, name, node, environment) {
if (environment.head.hasOwnProperty(name)) {
const descriptors = Object.getOwnPropertyDescriptors(environment.head);
return (0, exports.handleRuntimeError)(context, new errors.VariableRedeclaration(node, name, descriptors[name].writable));
}
environment.head[name] = DECLARED_BUT_NOT_YET_ASSIGNED;
return environment;
}
exports.declareIdentifier = declareIdentifier;
const currentEnvironment = (context) => context.runtime.environments[0];
exports.currentEnvironment = currentEnvironment;
function defineVariable(context, name, value, constant = false, node) {
const environment = (0, exports.currentEnvironment)(context);
if (environment.head[name] !== DECLARED_BUT_NOT_YET_ASSIGNED) {
return (0, exports.handleRuntimeError)(context, new errors.VariableRedeclaration(node, name, !constant));
}
Object.defineProperty(environment.head, name, {
value,
writable: !constant,
enumerable: true
});
return environment;
}
exports.defineVariable = defineVariable;
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