expression-compiler

expression

fun with math expressions

Install

$ npm install expression-compiler

Usage

> var compile = require('expression');
undefined
> var var exprFn = compile('c*sin(2*t)+1');
undefined
> exprFn({c: 0.5, sin: Math.sin, t: Math.PI});
0.9999999999999999

Parsing

New AST node design:

{
  id: 0,
  type: 'ASTNode',
  node: 'expr',
  template: '#',
  children: [],
  options: {}
}

• id must be unique
• type must be a valid node type
• options contains different properties depending on the node type

AST Node Types

expr

options:

{}

func

options:

{
  key: 'funcName'
}

Infix functions should be normal function nodes. Here are some examples for + with 2 or 3 operands:

{
  id: 0,
  type: 'ASTNode',
  node: 'func',
  template: '# + # + #',
  children: [someNode, anotherNode, andAnother],
  options: {
    key: 'sum'
  }
}

Normal functions can take multiple arguments

{
  id: 0,
  type: 'ASTNode',
  node: 'func',
  template: 'min(#, #)',
  children: [someNode, anotherNode],
  options: {
    key: 'min'
  }
}

name

options:

{
  key: 'varName'
}

literal

options:

{
  value: 1
}