env: isVariable()

This function is used to determine if an object is of Variable class. It is used internally by unify().

isVariable() is defined in env and can be accessed like that:

import {isVariable} from 'deep6/env.js';

The current implementation:

const isVariable = x => x instanceof Variable;

Example of use:

import {isVariable, variable} from 'deep6/env.js';

const x = variable();

isVariable(x); // true
isVariable(1); // false