excel-formula-ast

Abstract syntax tree for excel formulas.

Install

npm install excel-formula-ast -S

or

yarn add excel-formula-ast

Usage

``js
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

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

$3

Build expression tree from tokens.

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

Returns: ast node

$3

Send a visitor through the tree nodes.

- tree: ast node
- visitor: object

#### visitor

Visitor is an object with any of these function properties:

`js
{
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

$3

Passed to visitor methods: enterCell, exitCell

Properties:

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

$3

Passed to visitor methods: enterCellRange, exitCellRange

Properties:

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

$3

Passed to visitor methods: enterFunction, exitFunction

Properties:

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

$3

Passed to visitor methods: enterNumber, exitNumber

Properties:

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

$3

Passed to visitor methods: enterText, exitText

Properties:

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

$3

Passed to visitor methods enterLogical, exitLogical

Properties:

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

$3

Passed to visitor methods: enterBinaryExpression, exitBinaryExpression

Properties:

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

$3

Passed to visitor methods: enterUnaryExpression, exitUnaryExpression

Properties:

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

License

MIT