mathjs/lib/esm/expression/operators.js

// list of identifiers of nodes in order of their precedence
// also contains information about left/right associativity
// and which other operator the operator is associative with
// Example:
// addition is associative with addition and subtraction, because:
// (a+b)+c=a+(b+c)
// (a+b)-c=a+(b-c)
//
// postfix operators are left associative, prefix operators
// are right associative
//
// It's also possible to set the following properties:
// latexParens: if set to false, this node doesn't need to be enclosed
//              in parentheses when using LaTeX
// latexLeftParens: if set to false, this !OperatorNode's!
//                  left argument doesn't need to be enclosed
//                  in parentheses
// latexRightParens: the same for the right argument
import { hasOwnProperty } from '../utils/object.js';
export var properties = [{
  // assignment
  AssignmentNode: {},
  FunctionAssignmentNode: {}
}, {
  // conditional expression
  ConditionalNode: {
    latexLeftParens: false,
    latexRightParens: false,
    latexParens: false // conditionals don't need parentheses in LaTeX because
    // they are 2 dimensional

  }
}, {
  // logical or
  'OperatorNode:or': {
    associativity: 'left',
    associativeWith: []
  }
}, {
  // logical xor
  'OperatorNode:xor': {
    associativity: 'left',
    associativeWith: []
  }
}, {
  // logical and
  'OperatorNode:and': {
    associativity: 'left',
    associativeWith: []
  }
}, {
  // bitwise or
  'OperatorNode:bitOr': {
    associativity: 'left',
    associativeWith: []
  }
}, {
  // bitwise xor
  'OperatorNode:bitXor': {
    associativity: 'left',
    associativeWith: []
  }
}, {
  // bitwise and
  'OperatorNode:bitAnd': {
    associativity: 'left',
    associativeWith: []
  }
}, {
  // relational operators
  'OperatorNode:equal': {
    associativity: 'left',
    associativeWith: []
  },
  'OperatorNode:unequal': {
    associativity: 'left',
    associativeWith: []
  },
  'OperatorNode:smaller': {
    associativity: 'left',
    associativeWith: []
  },
  'OperatorNode:larger': {
    associativity: 'left',
    associativeWith: []
  },
  'OperatorNode:smallerEq': {
    associativity: 'left',
    associativeWith: []
  },
  'OperatorNode:largerEq': {
    associativity: 'left',
    associativeWith: []
  },
  RelationalNode: {
    associativity: 'left',
    associativeWith: []
  }
}, {
  // bitshift operators
  'OperatorNode:leftShift': {
    associativity: 'left',
    associativeWith: []
  },
  'OperatorNode:rightArithShift': {
    associativity: 'left',
    associativeWith: []
  },
  'OperatorNode:rightLogShift': {
    associativity: 'left',
    associativeWith: []
  }
}, {
  // unit conversion
  'OperatorNode:to': {
    associativity: 'left',
    associativeWith: []
  }
}, {
  // range
  RangeNode: {}
}, {
  // addition, subtraction
  'OperatorNode:add': {
    associativity: 'left',
    associativeWith: ['OperatorNode:add', 'OperatorNode:subtract']
  },
  'OperatorNode:subtract': {
    associativity: 'left',
    associativeWith: []
  }
}, {
  // multiply, divide, modulus
  'OperatorNode:multiply': {
    associativity: 'left',
    associativeWith: ['OperatorNode:multiply', 'OperatorNode:divide', 'Operator:dotMultiply', 'Operator:dotDivide']
  },
  'OperatorNode:divide': {
    associativity: 'left',
    associativeWith: [],
    latexLeftParens: false,
    latexRightParens: false,
    latexParens: false // fractions don't require parentheses because
    // they're 2 dimensional, so parens aren't needed
    // in LaTeX

  },
  'OperatorNode:dotMultiply': {
    associativity: 'left',
    associativeWith: ['OperatorNode:multiply', 'OperatorNode:divide', 'OperatorNode:dotMultiply', 'OperatorNode:doDivide']
  },
  'OperatorNode:dotDivide': {
    associativity: 'left',
    associativeWith: []
  },
  'OperatorNode:mod': {
    associativity: 'left',
    associativeWith: []
  }
}, {
  // unary prefix operators
  'OperatorNode:unaryPlus': {
    associativity: 'right'
  },
  'OperatorNode:unaryMinus': {
    associativity: 'right'
  },
  'OperatorNode:bitNot': {
    associativity: 'right'
  },
  'OperatorNode:not': {
    associativity: 'right'
  }
}, {
  // exponentiation
  'OperatorNode:pow': {
    associativity: 'right',
    associativeWith: [],
    latexRightParens: false // the exponent doesn't need parentheses in
    // LaTeX because it's 2 dimensional
    // (it's on top)

  },
  'OperatorNode:dotPow': {
    associativity: 'right',
    associativeWith: []
  }
}, {
  // factorial
  'OperatorNode:factorial': {
    associativity: 'left'
  }
}, {
  // matrix transpose
  'OperatorNode:transpose': {
    associativity: 'left'
  }
}];
/**
 * Get the precedence of a Node.
 * Higher number for higher precedence, starting with 0.
 * Returns null if the precedence is undefined.
 *
 * @param {Node} _node
 * @param {string} parenthesis
 * @return {number | null}
 */

export function getPrecedence(_node, parenthesis) {
  var node = _node;

  if (parenthesis !== 'keep') {
    // ParenthesisNodes are only ignored when not in 'keep' mode
    node = _node.getContent();
  }

  var identifier = node.getIdentifier();

  for (var i = 0; i < properties.length; i++) {
    if (identifier in properties[i]) {
      return i;
    }
  }

  return null;
}
/**
 * Get the associativity of an operator (left or right).
 * Returns a string containing 'left' or 'right' or null if
 * the associativity is not defined.
 *
 * @param {Node} _node
 * @param {string} parenthesis
 * @return {string|null}
 * @throws {Error}
 */

export function getAssociativity(_node, parenthesis) {
  var node = _node;

  if (parenthesis !== 'keep') {
    // ParenthesisNodes are only ignored when not in 'keep' mode
    node = _node.getContent();
  }

  var identifier = node.getIdentifier();
  var index = getPrecedence(node, parenthesis);

  if (index === null) {
    // node isn't in the list
    return null;
  }

  var property = properties[index][identifier];

  if (hasOwnProperty(property, 'associativity')) {
    if (property.associativity === 'left') {
      return 'left';
    }

    if (property.associativity === 'right') {
      return 'right';
    } // associativity is invalid


    throw Error('\'' + identifier + '\' has the invalid associativity \'' + property.associativity + '\'.');
  } // associativity is undefined


  return null;
}
/**
 * Check if an operator is associative with another operator.
 * Returns either true or false or null if not defined.
 *
 * @param {Node} nodeA
 * @param {Node} nodeB
 * @param {string} parenthesis
 * @return {boolean | null}
 */

export function isAssociativeWith(nodeA, nodeB, parenthesis) {
  // ParenthesisNodes are only ignored when not in 'keep' mode
  var a = parenthesis !== 'keep' ? nodeA.getContent() : nodeA;
  var b = parenthesis !== 'keep' ? nodeA.getContent() : nodeB;
  var identifierA = a.getIdentifier();
  var identifierB = b.getIdentifier();
  var index = getPrecedence(a, parenthesis);

  if (index === null) {
    // node isn't in the list
    return null;
  }

  var property = properties[index][identifierA];

  if (hasOwnProperty(property, 'associativeWith') && property.associativeWith instanceof Array) {
    for (var i = 0; i < property.associativeWith.length; i++) {
      if (property.associativeWith[i] === identifierB) {
        return true;
      }
    }

    return false;
  } // associativeWith is not defined


  return null;
}