jstangroome

#requires -version 2.0
[CmdletBinding()]
param (
    [parameter(Mandatory=$true)]
    [ValidateScript({ Test-Path -Path $_ -PathType Leaf })]
    [string]
    $Path
)

$ErrorActionPreference = 'Stop'

chambart

type zero = unit
type 'a succ = unit -> 'a

type 'a nat =
  | Zero : zero nat
  | Succ : 'a nat -> 'a succ nat

module type T = sig
  type t
  val v : t nat

JSuder-xx

/** 
 * _Explicitly declare modifications_ to an existing object type via a fluent interface which yields a mapping function 
 * from the original data type to the type derived from the modification commands. 
 * 
 * The value over authoring a simple mapping function directly
 * * harder to make a mistake due to the explicit nature
 * * easier to read.
 * 
 * This is _not_ production quality code but rather a _proof of concept_ gist for applying conditional/mapped
 * types to mapper generation. A real-world usage might involve also generating the type-guard function

JSuder-xx

/**
 * When implementing the evaluation of a tree of expressions, an environment/context/memory representation is typically passed as an
 * argument (or injected into the constructor of the interpreter class for OO realizations of the pattern) in order to give the 
 * expressions access to a memory store. 
 * 
 * The *Type* of the memory does not normally relate to any specific constructed expression ex. the memory may be implemented as an
 *  _arbitrary_ dictionary of key/value pairs. As such, there is no way to know if a type or instance of a dictionary of values can
 *  satisfy the needs to a specific constructed expression.
 * 
 * For example, the following expression reads a number named 'x' from the environment and therefore the expression _requires_ an x of type number

JSuder-xx

/**
 * Imagine a Fluent Builder where some subset of the fluent methods are valid to call
 * * after one or more fluent methods have been called
 * * before one or more fluent methods have been called
 * * limited number of times.
 * 
 * There is no way to enforce such constraints in statically typed languages such as C++, C# or Java when using a single builder
 * class/interface. Developers would need to author many interfaces to represent the different shapes and would likely need to 
 * author many versions of the builder itself (proxies with a specific signature delegating to an underlying source builder). 
 * 

JSuder-xx

/** Micro Api for building type predicates */
module TypePredicateApi {
    export type TypePredicate<refined> = (val: any) => val is refined;
    export type TypeOfTypePredicate<refiner> = refiner extends TypePredicate<infer refined> ? refined : never;
    export type TypePredicateMap = { [propertyName: string]: TypePredicate<any> }
    export type ObjectFromTypePredicateMap<map extends { [propertyName: string]: TypePredicate<any> }> = {
        [propertyName in keyof map]: TypeOfTypePredicate<map[propertyName]>;
    }

    /** Create a predicate which tests for an object. */