@hugov/math-code NPM

math-code

small and minimal math equation system parser

Example • Syntax • Workings • ToDo • License

Example

make(`
wage = L(45, 55, city, work)
rent = L(15, 25, city)
cost = L(15, 20, city, -work) //work less, spend more!

save = pow(wage - rent - cost, 1 + N(1,2)%)
`)() // => { wage, rent, cost, save }

Syntax

Syntax is the same as Javascript with the following exceptions:

Object properties (a[0], a.x) are not permitted
Variable names prototype, toString, constructor, valueOf, toLocaleString are not permitted
Variables are automatically declared. No variable declaration (var a)
Percent sign (%) is converted to /100
All Math functions (cos, log, ...) and values (PI, ...) are global, along with the following random function generators.
- Z() => random unit normal number
- N(low, high [, ...risk factors]) => random normal number, 50% of times between low and high
- L(low, high [, ...risk factors]) => random lognormal number, 50% of times between low and high
- W(low, high [, ...risk factors]) => t => random normal number sum
- R(low, high [, ...risk factors]) => t => random normal number product
Random number generators can have additional risk factor unit normal seeds for corrolated variables. For simplicity, the independent portion counts as one. For example, X = N(low, high, riskA, riskB) generates a random number from the unit normal seed z = ( Z() + riskA + riskB ) / 3

Workings

For the given input string:

  random = N(12, 34, a, b, c)

the following code gets compiled:

function(v) {
  this.a = this.Z()
  this.b = this.Z()
  this.c = this.Z()
  v.random = this[1]()
  return v
}.bind({Z: require('random-z'), N: require('grosso-modo').norm: , cos: Math.cos, //...and more
  0: N(12, 34),
  1: function() { return this[0]( this.Z() + this.a + this.b + this.c / 4 ) }
}, {v: 1})

ToDo

test negative correlation
? allow inline comments
? return to Math namespace to avoid blocking common variable names (max, min, ...)
? y = Init(1) | Init.y = 1 for run-once recursive
? allow prototype by using hasOwnProperty