Part1

Imports

import Json.Decode as D exposing (Decoder)
import Json.Decode.Pipeline as D
import Json.Encode as E exposing (Value)

Record

type alias User =
 { name : String
 , age : Int
 }

Decoder — All fields required

If any of the fields are missing or have invalid type, following decoder will fail.

userDecoder : Decoder User
userDecoder =
    D.succeed User
        |> D.required "name" D.string
        |> D.required "age" D.int

Success Example:

> D.decodeString userDecoder """{"name": "Jack", "age": 25 }"""
Ok { name = "Jack", age = 25 } : Result.Result String Repl.User

Failure Example: age field missing

> D.decodeString userDecoder """{"name": "Jack"}"""
Err "Expecting an object with a field named `age` but instead got: {\"name\":\"Jack\"}"
    : Result.Result String Repl.User

Decoder — Age optional

if age feild is missing, then following decoder will default its value to one specified. (3rd argument to D.optional function)

userDecoder : Decoder User
userDecoder =
    D.succeed User
        |> D.required "name" D.string
        |> D.optional "age" D.int 0

Success Example: age field missing

> D.decodeString userDecoder """{"name": "Jack"}"""
Ok { name = "Jack", age = 0 } : Result.Result String Repl.User

Success Example: age field present

> D.decodeString userDecoder """{"name": "Jack", "age": 25 }"""
Ok { name = "Jack", age = 25 } : Result.Result String Repl.User

CAUTION

If the optional field is present then it will be decoded using specified decoder, which may result in failure.

Failure Example: age field present, but not int compatable

> D.decodeString userDecoder """{"name": "Jack", "age": "25" }"""
Err "I ran into a `fail` decoder: I ran into the following problems:\n\nExpecting an Int but instead got: \"25\"\nExpecting null but instead got: \"25\""
    : Result.Result String Repl.User

Complete example

Elm: Decode fields that might be absent in JSON was originally published in The Functional Programmer on Medium, where people are continuing the conversation by highlighting and responding to this story.

In Elm, JSON encoding and decoding is quite easy as opposed to what people think. The main problem is lack of good examples. I have struggled a lot, and have found answers to almost all of my conscerns. Thanks to awesome Elm Community.

Following is what I intend to cover in this series

• Decode JSON objects to Elm Records (current article)
• Decode fields that might be absent in JSON
• Decode fields of type Maybe
• Decode simple Union Type
• Decode Single Constructor Union Type
• Decode Parameterised UnionType
• Decode any combination of above
• Encode any combination of above
• Strategies to deal with changing shape of types when our application grows
• Using Versions to maintain backward compatibility
• Strategies to handle decoding errors

Decoding JSON objects to Elm Records

We can send Javascript objects directly over ports. There is no need to JSON encode them. Once received we can use Json.Decode.decodeValue

port onSomeEvent : (D.Value -> msg) -> Sub msg

Let’s define type alias for SomeEvent

type alias SomeEvent =
    { name : String
    , age : Int
    }

Now let’s write a decoder for it

someEventDecoder = 
    D.succeed SomeEvent
        |> DP.required "name" D.string
        |> DP.required "age" D.int

As a convention, I rarely import any module directly. Using namespace prefix is prefered. So what is D and DP?

import Json.Encode as E
import Json.Decode as D
import Json.Decode.Pipeline as DP

Using the pipeline library allows to use the required function with |> operator.

Now to get the result of decoding we can simply write

decodeSomeEvent: D.Value -> Result String SomeEvent
decodeSomeEvent encoded = someEventDecoder |> D.decodeValue encoded

And we are done, well almost. Now it is up to us how to handle the failure case.

Until next time. Enjoy Elm!

P.S. With enough support and encouragement, I would like to write a tool that will automate this process completely.

I love Elm, and would like to help anyone who is stuck because of lack of tutorials or examples. Feel free to write to me.

How to Decode JSON in Elm Part 1 was originally published in The Functional Programmer on Medium, where people are continuing the conversation by highlighting and responding to this story.

• A list of Do’s and Dont’s.
• With judgements on what’s Right and Wrong.
• Filled with Zelots and Moderates alike.

Avoid religious debates!

• Just take the #GoodStuff
• Just Take It And Go

Programming Languages are Half-Part Religion was originally published in The Functional Programmer on Medium, where people are continuing the conversation by highlighting and responding to this story.

This beautiful poem hit home, and made me realize why I am afraid of any long-term relationship.

New Status: “Interested”

But only with someone who shares these beautiful thoughts:

All Credits to Demetra Demi Gregorakis and her following words

I’m Sorry I’m Not Always The Sun.

I’m sorry I’m not always the sun.

Don’t love me when I’m only the sun
love me when I burn you,
love me when my rays are too much for you to see,
love me when I can’t see my own worth.

I need you to love me when I’m the cloud,
when I’m the storm,
when I’m flooding my mind with worries and doubts,
i need you to take hold of me,
to wrap your arms around me,
to bring me back to this moment of you and I,
to calm me.

i need you to love me more than just a like on a photo
i need you more than just a ‘good morning’ and ‘good night’ text
i need to know that you are there at 3 am
when the world is quiet and my mind is awake,
that you take my secrets and hold them locked in your soul,
I need to know my words are safe in your hands,
that you hold my heart as one of the seven wonders of the world,
the finest treasure to ever have been discovered.

I need to know that you aren’t temporary,
I know you can’t promise that,
but,
In this world of instant gratification,
I need to know you believe in working at us
I need to believe that you aren’t a ghost
I need you to be my lighthouse
when I’m lost at sea,

don’t leave me shipwrecked.

but if you must leave, leave me wearing a life vest, leave me on shore, leave me with honesty, leave me with my sanity.

i need you to understand me, because i don’t understand me,

i need you to accept me.

i need you to love all parts of me
because no, I’m not always the sun,
and sometimes you’ll need to radiate for me,

I’m sorry I’m not always the sun,

but I can promise when you are the cloud — I will alway shine for you.

I promise I’m worth the storm.

The Not So Impossible Target

It has been proved that it can be done. Somewhere around 1940’s some guy proposed using functions as basis for mathematics and computation, and this theory also ended up being Turing Complete.

But WHY!

I was inspired by the Ruby Version of this fun little experiment by Tom Stuart. And it seems like a fun exercise. And I have another hidden agenda :D

So, lets define todays target.

Define

• Write a traditional solution to FizzBuzz in javascript.
• Write a test.
• Push to GitHub
• Try to make small changes such that our test doesn’t break.
• Try to Remove at least 2 language features by EOD.
• Blog at EOD.

Phew!

Here we go, the entire FizzBuzz program just using functions. Also uploaded to GitHub.

#Experiment 3: Can I solve FizzBuzz using ONLY JS functions, and ABSOLUTELY nothing else was originally published in The Functional Programmer on Medium, where people are continuing the conversation by highlighting and responding to this story.

Scroll for “EOD update”

But

It is already 3pm, and I don’t want to set up myself for failure. So, let’s reduce the requirement.

Define

• Setup Haskell environment.
• Setup Haskell web/javascript development environment.
• Learn about Haskell html/JS libraries.
• Create a static HTML page, that displays current time in HH:MM:SS format.
• Export to GitHub.
• Blog

Next

• We shall migrate the Timer Chrome Extension
• But that’s not our today’s target. :D

EOD Results

• Installed Haskell Platform (~300Mb)
• Setup project using Haskell to JavaScript as reference (GHCJS).
• stack setup takes long time.
• Ran into some dependency resolution errors. Unsuccessfully spent time fixing them.
• So, decided to run exact copy of code from Haskell to JavaScript
• Ended the day while stack setup was running.
• No success, still getting bunch of errors :(
• Pushed to GitHub haskell-timer-chrome-ext with the errors.

Notes

• We can try compiling Haskell to JS by using Haste compiler instead of GHCJS.
• Or use Purescript, which is very similar to haskell.
• Or just stick to writing functional code in JS itself, using Ramda The Ultimate :D
• But that will be for “#Experiment Day 3 “

#Experiment Day 2: Javascript To Haskell was originally published in The Functional Programmer on Medium, where people are continuing the conversation by highlighting and responding to this story.

The Concern

I have been working on multiple projects since last few weeks. Daily making decent progress. But recently, I feel dissatisfied by end of the day.

The Epiphany

Yesterday, I had an epiphany. “Can I define, code and ship, a minimal chrome extension, before end of the day? Let's see :D”

The Definition

• Recurring timer beeps every 25m.
• Click to activate or press ctrl+shift+9.
• Icon colour shows status.

And voila! Here is the brand new Chrome Extension uniquely named Timer. It took around 4hrs to get it done.

The Conclusion

There is none. But then I had another epiphany.

• “What if I define, ship and blog about work, on daily basis?”
• “It should lead to sweet satisfaction at the end of the day”

Let the experiment begin!

Define, Ship and Blog Daily was originally published in The Functional Programmer on Medium, where people are continuing the conversation by highlighting and responding to this story.

How to quickly select any text

• double/triple click on first/last word,
• don’t lift the mouse
• Now just drag.

You no longer have to click at the precise start of the word to begin selection, Kaboom!

Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now,

How to select text within links. Muahahaha!

• hold ctrl+alt key, while dragging with single/double/triple click.
• some browsers will open tab in background, small price to pay.

Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now, Try it now,

How to select long text without the painfully slow “drag-scroll”

• Click at the start/end of text you want to select
• Then just scroll till end position is in view
• Now shift click at the end.

Go on! try it now on this page.

Like, share, recommend. Make me happy!

Hearthstone Deck Tracker - Deck and stats tracking for Hearthstone

Tip #1 Install “Hearthstone Deck Tracker” was originally published in Hearthstone Adventures on Medium, where people are continuing the conversation by highlighting and responding to this story.

But you take away that which you gave for free, Fuck You for that.

Personally, I was more than happy with an old notekeeping, windows only software called. “Keynote” (Not to be confused with Mac OSX’s presentation/slides app of the same name.)

But it was windows only, so no sync, no multi device usage. :(

I have tried google docs, google keep, simplenote, they all suck in one way or another. Evernote was horrible too, but least so compared to alternatives.

One has to use “Keynote” in order to appreciate it. And only then one can realize why all the other note taking apps suck. (Special wink to Kalpesh Bhai)

So readers, if you have any other recommendation do let me know. Right now I am contemplating re-re-re-starting my simpleoutliner project.

And If I do, I shall list in detail what features are crucial for a personal note taking application.

Meanwhile…

“Fuck You EverNote”