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2e51086fda
'isAssociativeWith(a,b)' to check if a is associative with b. Example: '+' is associative with '-' because (a+b)-c=a+(b-c)
74 lines
2.6 KiB
JavaScript
74 lines
2.6 KiB
JavaScript
var assert = require('assert');
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var operators = require('../../lib/expression/operators');
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var OperatorNode = require('../../lib/expression/node/OperatorNode');
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var AssignmentNode = require('../../lib/expression/node/AssignmentNode');
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var ConstantNode = require('../../lib/expression/node/ConstantNode');
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var Node = require('../../lib/expression/node/Node');
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describe('operators', function () {
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it('should return the precedence of a node', function () {
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var a = new ConstantNode(1);
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var b = new ConstantNode(2);
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var n1 = new AssignmentNode('a', a);
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var n2 = new OperatorNode('or', 'or', [a, b]);
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assert.equal(operators.getPrecedence(n1), 0);
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assert.equal(operators.getPrecedence(n2), 2);
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});
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it('should return null if precedence is not defined for a node', function () {
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var n = new Node();
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assert.equal(operators.getPrecedence(n), null);
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});
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it('should return the associativity of a node', function () {
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var a = new ConstantNode(1);
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var n1 = new OperatorNode('+', 'add', [a, a]);
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var n2 = new OperatorNode('^', 'pow', [a, a]);
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var n3 = new OperatorNode('-', 'unaryMinus', [a]);
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var n4 = new OperatorNode('!', 'factorial', [a]);
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assert.equal(operators.getAssociativity(n1), 'left');
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assert.equal(operators.getAssociativity(n2), 'right');
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assert.equal(operators.getAssociativity(n3), 'right');
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assert.equal(operators.getAssociativity(n4), 'left');
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});
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it('should return null if associativity is not defined for a node', function () {
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var a = new ConstantNode(1);
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var n1 = new Node();
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var n2 = new AssignmentNode('a', a);
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assert.equal(operators.getAssociativity(n1), null);
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assert.equal(operators.getAssociativity(n2), null);
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});
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it('should return if a Node is associative with another Node', function () {
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var a = new ConstantNode(1);
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var n1 = new OperatorNode('+', 'add', [a, a]);
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var n2 = new OperatorNode('-', 'subtract', [a, a]);
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assert.equal(operators.isAssociativeWith(n1, n1), true);
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assert.equal(operators.isAssociativeWith(n1, n2), true);
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assert.equal(operators.isAssociativeWith(n2, n2), false);
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assert.equal(operators.isAssociativeWith(n2, n1), false);
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});
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it('should return null if the associativity between two Nodes is not defined', function () {
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var a = new ConstantNode(1);
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var n1 = new Node();
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var n2 = new AssignmentNode('a', a);
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assert.equal(operators.isAssociativeWith(n1, n1), null);
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assert.equal(operators.isAssociativeWith(n1, n2), null);
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assert.equal(operators.isAssociativeWith(n2, n2), null);
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assert.equal(operators.isAssociativeWith(n2, n1), null);
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});
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});
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