WJH wongjiahau

Lambdas using Let Notation

Introduction

As we all know, let expression is actually just a syntactic sugar for immediately invoked lambda expression (IILA). Actually not entirely correct, as pointed out in this comment.

For example, in Haskell:

let x = a in b

is the same as

	// Note: the following grammar has not yet included Unary Tree
	Ibx {
	Exp
	= BinaryExp

	BinaryExp
	= BinaryExp PriExp PriExp -- BinaryExp
	\| PriExp

	PriExp

	"use strict";

	Object.defineProperty(exports, "__esModule", {
	value: true
	});
	exports.execute = execute;
	exports.executeSync = executeSync;
	exports.assertValidExecutionArguments = assertValidExecutionArguments;
	exports.buildExecutionContext = buildExecutionContext;
	exports.collectFields = collectFields;

	export const modus_ponens
	// Proposition
	// Given: A => B and A
	// We can conclude: B
	: <A, B>(f: (a: A) => B, a: A) => B
	= <A, B>(f: (a: A) => B, a: A) => f(a)

	// Note, in intuitionistic logic, ~A (a.k.a NOT A), is represented as A => never
	export const modus_tollens
	// Proposition:

	import * as _0 from 'https://deno.land/x/a0/mod.ts'
	import * as _1 from 'https://deno.land/x/cmd/mod.ts'
	import * as _2 from 'https://deno.land/x/adka_server/mod.ts'
	import * as _3 from 'https://deno.land/x/actdb/mod.ts'
	import * as _4 from 'https://deno.land/x/airtable/mod.ts'
	import * as _5 from 'https://deno.land/x/adka/mod.ts'
	import * as _6 from 'https://deno.land/x/abc/mod.ts'
	import * as _7 from 'https://deno.land/x/amqp/mod.ts'
	import * as _8 from 'https://deno.land/x/alosaur/mod.ts'
	import * as _9 from 'https://deno.land/x/ascii_table/mod.ts'

	/*
	Funcords is a feature that combine functions and records.

	If you think about it, record is actually a dependently typed function,
	where the output type depends on the input type.

	For example,

	r = {'x': 1, 'y': 'yo'}

	// Record type
	{}: `{}

	// construction
	{x = {}}: `{x: `{}}

	// destruction
	{x: `{}} = {x = {}}

	// abstraction