Demo

Simple calculation

const c = {
  a: 10,
  b: 20
}
const p = new Processor(c)
let r:any = null

r = p.run(`
  a+b;
  _r/7;
  .2;
`)
console.log(Object.keys(r), (r._r as Big).toNumber())

Processor supports + - * / as mathematical operators. _r is the intermediate result during the calculation process. Special operator . means round function Result r from Processor.run is the whole context Result r._r is the calculation result and its type is Big.

Special operator :

r = p.run(`
a-b;
:tmp;
tmp*6;
`)
console.log(Object.keys(r), (r._r as Big).toNumber(), (r.tmp as Big).toNumber())

Special operator : means create a new field in the context and save the intermediate result into this new field. The following calculation can use this new field.

Special operators \\

r = p.run(`
a-b;
\\abs;
`)
console.log(Object.keys(r), (r._r as Big).toNumber())

Special operator \\ means executing a Big function and using the intermediate result as the input parameter

Special operators !

const pf1 = new Processor(c, {
  demo1: (a:number, b:number) => {
    // return a Big instance will update the context._r
    // else the context._r will keep unchanged
    return Big(a + b)
  }
})
r = pf1.run(`
!demo1,a,b;
`)
console.log(Object.keys(r), (r._r as Big).toNumber())

Processor constructor accepts the 2nd input parameter as extension. You may provide your own extension functions here. Special operator ! means executing a Big function and using specified context fields as input parameters

const pf2 = new Processor(c, {
  demo2: (c:ContextType) => {
    console.log(c)
    // return a Big instance will update the context._r
    // else the context._r will keep unchanged
    return Big(c.a || 0).times(c.b || 0)
  }
})
r = pf2.run(`
!demo2;
`)
console.log(Object.keys(r), (r._r as Big).toNumber())

If no context fields specified, the whole context will be pass into the extension function as input parameter