marcmartino

const fibUntil = (prevSum: number, prevNums = [0,1]): number => {
    const nextNum = prevNums[0] + prevNums[1]

    return nextNum >= 4_000_000
        ? prevSum
        : fibUntil(
            prevSum + (nextNum % 2 === 0 ? nextNum : 0), 
            [prevNums[1], nextNum]
        )
}

marcmartino

Less Contrived Pattern Matching Example II

Another example of a nice use of pattern matching I came upon while practicing basic hs- pattern match over a tuple of two booleans that you're creating ad hoc. This is great because it avoids the nesting of ifs/ternaries and is more clear what's going on.

getClassification :: Int -> Int -> Classification
getClassification target aliquotSum =
  case (target > aliquotSum, target < aliquotSum) of
    (True, _) -> Deficient
 (_, True) -&gt; Abundant

marcmartino

import { TypeOf, Type, InputOf, OutputOf } from "io-ts"
import { matchW } from "fp-ts/Either"
import { reduce } from "fp-ts/Array"
import { flow } from "fp-ts/function"
import { ReactNode, PropsWithoutRef } from "react"
import { Form as FinalForm, FormProps as FinalFormProps } from "react-final-form"
export { FORM_ERROR } from "final-form"

export interface FormProps<C extends Type<TypeOf<C>, OutputOf<C>, InputOf<C>>>
  extends Omit<PropsWithoutRef<JSX.IntrinsicElements["form"]>, "onSubmit"> {

marcmartino

An Adventure in Optimizing Functional Code Speed

Continuing through my learning/exploration of elm I was tasked with coming up with a function for determining if a given list is an equal, sublist, superlist, or unrelated to another.

My initial solution looked like this

type ListComparison
    = Equal
    | Superlist
    | Sublist
    | Unequal

marcmartino

Less Contrived Pattern Matching Example

Working my way through beginner elm exercises I needed to write a function to remove leading zeros from a list and it turned out to be a great illustration of how nice pattern matching can be.

in js the solution would be something like

const removeLeadingZeros = (xs) => 
          xs[0] === 0 
 ? removeLeadingZeros(xs.slice(1)) 

marcmartino

Imperative v Functional

Many times introduction to functional material tends to focus on really facile aspects of functional programming like "Use map or reduce instead of a for loop". To me this doesn't do justice to what a beginner functional approach really should be.

A good example to display how different the two approaches can be would be a simple range function

Imperative

function  range(start, end, step = 1) {
  let  numBetween = [];
 const rangeStep = start < end ? Math.abs(step) : Math.abs(step) * -1;

marcmartino

/*
Copyright 2012 Jun Wako <[email protected]>

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of

marcmartino

  // Available variables:
  // - Machine
  // - interpret
  // - assign
  // - send
  // - sendParent
  // - spawn
  // - raise
  // - actions

marcmartino

let prod = false;

const getVizPromiseInput = () => {
  return document.getElementById("serviceInput").value;
};
const clearVizPromiseInput = () => {
  document.getElementById("serviceInput").value = "";
};
const disableViz = () => {

marcmartino

const setSpeechNodeContext = (lang, text) =>
  assign({
    speechText: text,
    speechLanguage: lang,
  });

const setListenNodeContext = (lang, conditions) =>
  assign({
    listenConditions: conditions,