Brief

This makes an array typed even in a length part.

Summary

we cannot assign an length 4 array to an lenth 3 array-arg with this.

let __a = WrapArray([0,1,2,3], V4)
let __b: TWrapArray<number, T3> = __a // <= error.

> error TS2322: Type 'TWrapArray<number, T4>' is not assignable to type 'TWrapArray<number, T3>'.

And values returned with inWrap- functions keeps a length info.

let __c : TWrapArray<number, T3> = inWrapRest(__a)
let __d : TWrapArray<number, T2> = inWrapRest(__a) // <= error.
let __e : TWrapArray<number, T5> = inWrapConj(__a, 4)
let __f = WrapArray([0,1,2,3], V4)
let __g : TWrapArray<number, TLesserUnion<T4>> = inWrapRest(__f)
__g = inWrapRest(__g)

> error TS2322: Type 'TWrapArray<number, T3>' is not assignable to type 'TWrapArray<number, T2>'.

The way of translating normal arrays by js is using of WrapArray/UnwrapArray.
This works as identity fn.

UnwrapArray(WrapArray([0,1,2,3],V4))

As above, TELesserUnion/TLesserUnion is used in the case we don't know the specific length but it should be the same or less than some number.

let __h: TWrapArray<number, TELesserUnion<T4>> = inWrapFilter((x:number)=> 2 > x , __a)
__h = WrapArray([4,5,6,7], V4)
__h = WrapArray([4,5,6,7,8], V5) // <= error.

> error TS2322: Type 'TWrapArray<number, T5>' is not assignable to type 'TWrapArray<number, Tzero | T1 | T2 | T3 | T4>'

Functions

Numbers

• Tzero, T1 ~ T10
• Vzero, V1 ~ V10
  They are predefined peano-numbers.
  The 1st are used in type level, passed into TWrapArray or type level culculate or something.
  The 2nd are values, passed into WrapArray's 2nd arg or so.

Util

• RtoV, VtoR
  They convert a real number to a peano and vice versa, useful for debug.

• Tadd, Tmin, Vmul

• Vadd, Vmin, Vmul
  All are two arg functions, culculating as +, -, *.
  Vmin's 2nd arg should be equal to or less than 1st, or it spits a type error.

• TLesserUnion

• TELesserUnion
  They get a type-level number, then return an union type, elements of which are equal to (with 2nd) or less than the number passed.

Functions

Those order of args and name are decided in reference to clojure fns.

(Array and Number written below are wrapped-array and peano-number implicitly.)

• inWrapGet: Array -> Number -> T
  Type error if 2nd is grater than a length of 1st.

• inWrapRest: Array -> Array
  This removes a head and dec a length.

• inWrapConj: Array -> T -> Array
  This pushes a value into a tail and inc a length.

• inWrapTake, inWrapDrop: Number -> Array -> Array
  It splits an array to two part at an index, 1st arg, then inWrapTake returns the left-part and inWrapDrop right-part.
  In js, it can be translated to slice(0,n) and slice(n,length).

They spits out a type error if an passed index is grater than a length of 2nd (the same as inWrapGet).

• inWrapConcat: Array -> Array -> Array
• inWrapFilter, inWrapRemove: (T -> boolean) -> Array -> Array

Author

https://github.com/taiyakihitotsu

License

3-clause BSD license