Add New Haskell Cheat Sheet #3711

haltode · 2016-10-23T12:55:08Z

Type of Change

Description of new Instant Answer, or changes

New cheat sheet for the Haskell language including basic features (data types, operations, comparators, IO, enumerations, lists, tuples, functions, control flow).

Related Issues and Discussions

People to notify

IA Page: https://duck.co/ia/view/haskell_cheat_sheet

daxtheduck · 2016-10-23T12:55:09Z

@napnac Thanks for the pull request! Unfortunately, we're only accepting contributions and improvements to a limited portion of the search space.

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If this is related to the Programming Mission, it will be reviewed by staff and the community as soon as possible!

daxtheduck · 2016-10-23T12:55:10Z

Haskell Cheat Sheet

Description: When you search for "haskell cheat sheet," you should get a cheat sheet about the Haskell Language.

Example Query: Haskell Cheat Sheet

Tab Name: Cheat Sheet

Source:

These are the important fields from the IA page. Please check these for errors or missing information and update the IA page

This is an automated message which will be updated as changes are made to the IA page

GuiltyDolphin · 2016-10-23T13:02:27Z

share/goodie/cheat_sheets/json/haskell.json

+            },
+            {
+                "key": "1.42",
+                "val": "Floating Point"


Float (or Double, or other Fractional).

GuiltyDolphin · 2016-10-23T13:02:44Z

share/goodie/cheat_sheets/json/haskell.json

+            },
+            {
+               "key": "'a'",
+               "val": "Character"


GuiltyDolphin · 2016-10-23T13:02:57Z

share/goodie/cheat_sheets/json/haskell.json

+            },
+            {
+               "key": "True",
+               "val": "Boolean"


GuiltyDolphin · 2016-10-23T13:03:17Z

share/goodie/cheat_sheets/json/haskell.json

+            },
+            {
+               "key": "[1, 2, 3]",
+               "val": "List"


GuiltyDolphin · 2016-10-23T13:03:38Z

share/goodie/cheat_sheets/json/haskell.json

+            },
+            {
+               "key": "(1, 4.2)",
+               "val": "Tuple"


(Int, Float)

GuiltyDolphin · 2016-10-23T13:07:54Z

@napnac I think you should approach this cheat sheet from a different point of view; instead of mentioning specific use-cases for some of the basic functions, I think it would be more helpful to cover the basic, common AlgDTs and their uses, along with some of the typeclasses.

haltode · 2016-10-23T13:12:47Z

@GuiltyDolphin Absolutely! But this cheat sheet right now is the bare minimum since there was none for Haskell. We can totally add more things to it in the future :)

GuiltyDolphin · 2016-10-23T14:44:35Z

share/goodie/cheat_sheets/json/haskell.json

+               "val": "(Int, Float)"
+            }
+        ],
+        "Basic Operations": [


I think it would be more useful to mention the Fractional, Integral, and Num type classes; operators in the arithmetical sense are pretty easy to figure out.

GuiltyDolphin · 2016-10-23T14:45:14Z

share/goodie/cheat_sheets/json/haskell.json

+               "val": "Integer division"
+            }
+        ],
+        "Comparators": [


As above, but with Ord and Eq.

GuiltyDolphin · 2016-10-23T14:45:58Z

share/goodie/cheat_sheets/json/haskell.json

+              "val": "Prints the string \"Hello!\""
+           },
+           {
+              "key": "input <- getLine",


Just use getLine, this makes no sense without the notion of 'do' notation.

GuiltyDolphin · 2016-10-23T14:47:50Z

share/goodie/cheat_sheets/json/haskell.json

+        ],
+        "Enumerations": [
+            {
+               "key": "[1 .. 5]",


We can probably just mention the syntaxes of [start..], [start,next..stop], and [start..stop].

GuiltyDolphin · 2016-10-23T14:48:10Z

share/goodie/cheat_sheets/json/haskell.json

+               "val": "Infinite list of integers greater than or equal to 1"
+            }
+        ],
+        "Lists": [


I think we should mention list comprehensions.

GuiltyDolphin · 2016-10-23T14:48:37Z

share/goodie/cheat_sheets/json/haskell.json

+        ],
+        "Functions": [
+           {
+              "key": "func params",


f x y ...

GuiltyDolphin · 2016-10-23T14:49:09Z

share/goodie/cheat_sheets/json/haskell.json

+        ],
+        "Control Flow": [
+            {
+               "key": "str = if a < b then \"yes!\" else \"no\"",


Just use if cond then x else y.

haltode · 2016-10-23T15:22:21Z

Thanks for all feedbacks @GuiltyDolphin ! For your first two changes, should I add them in addition of what I already wrote or should I replace it ?

GuiltyDolphin · 2016-10-25T10:26:20Z

@napnac I think replacement would be better, but you could provide a (small) example of usage.

haltode · 2016-10-27T09:58:34Z

@GuiltyDolphin I only redid the 'Basic Operations' part because I didn't exactly know what you expected. I'm waiting for you feedbacks to start on the 'Comparators' part ;)

GuiltyDolphin · 2016-10-27T18:39:56Z

share/goodie/cheat_sheets/json/haskell.json

+         },
+         {
+            "key": "Num Int",
+            "val": "Num's instance for integer"


Remove this.

GuiltyDolphin · 2016-10-27T18:40:38Z

share/goodie/cheat_sheets/json/haskell.json

+         },
+         {
+            "key": "(+) :: Num a => a -> a -> a",
+            "val": "Example of a basic operation"


Numeric addition.

GuiltyDolphin · 2016-10-27T18:40:49Z

share/goodie/cheat_sheets/json/haskell.json

+         },
+         {
+            "key": "4.2 :: Fractional a => a",
+            "val": "Example of Fractional class"


Remove this.

GuiltyDolphin · 2016-10-27T18:40:53Z

share/goodie/cheat_sheets/json/haskell.json

+         },
+         {
+            "key": "2 :: Num a => a",
+            "val": "Example of Num class"


Remove this.

GuiltyDolphin · 2016-10-27T18:41:31Z

share/goodie/cheat_sheets/json/haskell.json

+         },
+         {
+            "key": "[start..]",
+            "val": "Infinite list"


Not always infinite (in fact, will usually be finite). It depends on the Enum implementation for the DT.

Sure, but how should I call it/describe it otherwise?

Just say that it iterates from 'start' to the maximum bound (if any).

GuiltyDolphin · 2016-10-27T18:41:46Z

share/goodie/cheat_sheets/json/haskell.json

+            "val": "Adds the letter A to the head of the list"
+         },
+         {
+            "key": "[x + y | x <- [1,2], y <- [1..5]]",


Show guards.

I don't understand what I need to add here.

Guards restrict which values pass through the (monadic) comprehension. For example [x | x <- [1..10], x > 7] would be equivalent to [8, 9, 10].

GuiltyDolphin · 2016-10-27T18:42:07Z

share/goodie/cheat_sheets/json/haskell.json

+      ],
+      "Tuples": [
+         {
+            "key": "fst (True, 'A')",


Use the name and type.

Again, I don't understand what you want me to replace. (Boolean, Char)?

fst : (a, b) -> a.

GuiltyDolphin · 2016-10-27T18:42:14Z

share/goodie/cheat_sheets/json/haskell.json

+            "val": "Accesses the first element of a tuple (only works on pair)"
+         },
+         {
+            "key": "snd (True, 'A')",


GuiltyDolphin · 2016-10-27T18:42:44Z

share/goodie/cheat_sheets/json/haskell.json

+         },
+         {
+            "key": "(\\x y -> x + y) 2 3",
+            "val": "Anonymous function that adds two variables (here we use the numbers 2 and 3 as an example)"


Don't need to say the bit in parens.

daxtheduck · 2016-10-28T08:53:14Z

Automated screenshot from beta.duckduckgo.com

Mobile screenshot

haltode · 2016-10-29T11:00:50Z

Thanks for the help @GuiltyDolphin ! I added another example of list comprehension with guards instead of overloading the first one, tell me if the rest is fine. ;)

daxtheduck · 2016-10-29T11:06:39Z

Automated screenshot from beta.duckduckgo.com

Mobile screenshot

moollaza · 2016-11-09T16:58:01Z

@napnac thanks for the awesome work.

@GuiltyDolphin the changes are now live on Beta: https://beta.duckduckgo.com/?q=Haskell+Cheat+Sheet&ia=cheatsheet

Any more updated needed? If not please merge!

daxtheduck · 2016-11-09T17:05:24Z

Automated screenshot from [beta.duckduckgo.com](https://beta.duckduckgo.com/?q=Haskell Cheat Sheet)

Mobile screenshot

daxtheduck · 2016-11-17T17:10:24Z

Automated screenshot from [beta.duckduckgo.com](https://beta.duckduckgo.com/?q=Haskell Cheat Sheet)

Mobile screenshot

pjhampton · 2017-03-06T18:34:37Z

ping @GuiltyDolphin. Is this good to merge?

kirkins · 2017-07-10T00:37:05Z

For code LGTM but I can't view it on beta even though it's active.

https://beta.duckduckgo.com/?q=Haskell+cheat+sheet

It seems like the software IA is triggered instead. Also tried aliases + "cheat sheet" and it didn't trigger.

mintsoft · 2017-08-15T22:20:24Z

There must be something funky going on with Beta here, I can't get this cheatsheet to show either

Has been addressed

mintsoft · 2017-08-23T22:07:14Z

Looks fine on duckpan, thanks @napnac

Added Haskell cheat sheet

13ede39

Fixed JSON syntax

61568eb

GuiltyDolphin suggested changes Oct 23, 2016

View reviewed changes

Required changes

2f3ff25

GuiltyDolphin suggested changes Oct 23, 2016

View reviewed changes

New changes requested

5d8cd63

moollaza mentioned this pull request Oct 26, 2016

New US State Capitals Cheat Sheet #3522

Closed

8 tasks

moollaza added New Instant Answer Programming Mission CheatSheet and removed Programming Mission labels Oct 26, 2016

daxtheduck deployed to beta.duckduckgo.com October 27, 2016 09:56 Active

Redid 'Basic Operations' section according to requested changes

3e3b4a7

Fixed indentation

5cf7615

daxtheduck deployed to beta.duckduckgo.com October 27, 2016 10:04 Active

tagawa added Programming Mission Topic: Haskell labels Oct 27, 2016

GuiltyDolphin previously requested changes Oct 27, 2016

View reviewed changes

daxtheduck deployed to beta.duckduckgo.com October 28, 2016 08:45 Active

Requested changes

c627022

daxtheduck deployed to beta.duckduckgo.com October 29, 2016 10:59 Active

Requested changes

961feea

moollaza added the Skill: JSON label Nov 9, 2016

moollaza changed the title ~~New cheat sheet : Haskell~~ New Haskell Cheat Sheet Nov 9, 2016

daxtheduck deployed to beta.duckduckgo.com November 9, 2016 16:46 Active

moollaza removed the Skill: JSON label Nov 9, 2016

moollaza assigned GuiltyDolphin Nov 9, 2016

moollaza changed the title ~~New Haskell Cheat Sheet~~ Add New Haskell Cheat Sheet Nov 9, 2016

daxtheduck deployed to beta.duckduckgo.com November 9, 2016 16:58 Active

sahildua2305 approved these changes Nov 9, 2016

View reviewed changes

tagawa added the Status: Needs Community Review label Nov 17, 2016

daxtheduck deployed to beta.duckduckgo.com November 17, 2016 17:03 Active

daxtheduck deployed to beta.duckduckgo.com December 20, 2016 14:08 Active

moollaza added the Priority: Low label Apr 20, 2017

mintsoft merged commit 9a58227 into duckduckgo:master Aug 23, 2017

Add New Haskell Cheat Sheet #3711

Add New Haskell Cheat Sheet #3711

Conversation

haltode commented Oct 23, 2016 • edited by jdorweiler

Type of Change

Description of new Instant Answer, or changes

Related Issues and Discussions

People to notify

daxtheduck commented Oct 23, 2016

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GuiltyDolphin commented Oct 23, 2016

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haltode commented Oct 23, 2016

GuiltyDolphin commented Oct 25, 2016

haltode commented Oct 27, 2016

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daxtheduck commented Oct 28, 2016

haltode commented Oct 29, 2016

daxtheduck commented Oct 29, 2016

moollaza commented Nov 9, 2016

daxtheduck commented Nov 9, 2016

daxtheduck commented Nov 17, 2016

pjhampton commented Mar 6, 2017

kirkins commented Jul 10, 2017 • edited

mintsoft commented Aug 15, 2017

mintsoft commented Aug 23, 2017

haltode commented Oct 23, 2016 •

edited by jdorweiler

daxtheduck commented Oct 23, 2016 •

edited

kirkins commented Jul 10, 2017 •

edited