excel-formula-ast

Abstract syntax tree for excel formulas.

Install

npm install excel-formula-ast -S

or

yarn add excel-formula-ast

Usage

const {tokenize} = require('excel-formula-tokenizer');
const {buildTree, visit} = require('excel-formula-ast');

const formula = 'SUM(1, 2)';
const tokens = tokenize(formula);

// build tree
const tree = buildTree(tokens);

// create visitor for parts of tree you're interested in
const visitor = {
  enterFunction(functionNode) {
    console.log(`function is ${functionNode.name}`);
  },
  enterNumber(numberNode) {
    console.log(`number is ${numberNode.value}`)
  }
};

// send visitor through tree
visit(tree, visitor);

// prints:
// function is SUM
// number is 1
// number is 2

API

const {buildTree, visit} = require('excel-formula-ast');

buildTree(tokens)

Build expression tree from tokens.

• tokens: Array of objects - Tokens from excel-formula-tokenizer (github | npm)

Returns: ast node

visit(tree, visitor)

Send a visitor through the tree nodes.

• tree: ast node
• visitor: object

visitor

Visitor is an object with any of these function properties:

{
  enterCell(node) {},
  exitCell(node) {},

  enterCellRange(node) {},
  exitCellRange(node) {},

  enterFunction(node) {},
  exitFunction(node) {},

  enterNumber(node) {},
  exitNumber(node) {},

  enterText(node) {},
  exitText(node) {},

  enterLogical(node) {},
  exitLogical(node) {},

  enterBinaryExpression(node) {},
  exitBinaryExpression(node) {},

  enterUnaryExpression(node) {},
  exitUnaryExpression(node) {}
}

For any node type Foo

• enterFoo() is called when the visitor gets to a Foo node.
• exitFoo() is called when the visitor has visited all of the Foo's child nodes (if any) and is leaving the Foo.

Node Types

cell

Passed to visitor methods: enterCell, exitCell

Properties:

• type: string - 'cell'
• key: string - Excel cell number. Example: 'A1'
• refType: string - 'relative' | 'mixed' | 'absolute'

cell range

Passed to visitor methods: enterCellRange, exitCellRange

Properties:

• type: string - 'cell-range'
• left: cell node
• right: cell node

function

Passed to visitor methods: enterFunction, exitFunction

Properties:

• type: string - 'function'
• name: string - function name
• arguments: Array of node

number

Passed to visitor methods: enterNumber, exitNumber

Properties:

• type: string - 'number'
• value: number

text

Passed to visitor methods: enterText, exitText

Properties:

• type: string - 'text'
• value: string

logical

Passed to visitor methods enterLogical, exitLogical

Properties:

• type: string - 'logical'
• value: boolean

binary expression

Passed to visitor methods: enterBinaryExpression, exitBinaryExpression

Properties:

• type: string - binary-expression
• operator: string
• left: node
• right: node

unary expression

Passed to visitor methods: enterUnaryExpression, exitUnaryExpression

Properties:

• type: string - 'unary-expression'
• operator: string
• operand: node

License

MIT