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Parse Error On Input If Haskell

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Do I need to do this? It's arguably allowed to have tab stops at 4,12,20,etc. It might help a little bit if you better explained what you are trying to do, or what you expect to be happening with the code you wrote. Not the answer you're looking for? have a peek here

Download Haskell Try Haskell in your browser Community Guidelines Other community locations: #haskell IRC channel Planet Haskell blog aggregator Follow Haskell on Twitter Haskell mailing lists NYC Haskell Meetup videos Professional more hot questions question feed lang-hs about us tour help blog chat data legal privacy policy work here advertising info mobile contact us feedback Technology Life / Arts Culture / Recreation Not the answer you're looking for? permalinkembedsaveparentgive gold[–]dave4420 6 points7 points8 points 2 years ago(3 children)GHC uses standard eight character wide tab stops. http://stackoverflow.com/questions/23463132/haskell-parse-error-on-input-if

Parse Error On Input Haskell

x = b? ghci> let (x:xs) = [1,2,3,4] ghci> x 1 ghci> xs [2,3,4] The way that you are using (x:xs) in your code hints that you do not yet have a firm grasp comment:7 Changed 13 months ago by thomie Differential Rev(s) set to Phab:D1309 Status changed from new to patch comment:8 Changed 13 months ago by simonmar Worth double-checking to see whether the GHC 7.0.1 and later). 1.2 If / Then / Else if-then statements must always include an 'else' portion.

You won't be able to vote or comment. 567Beginner - Parse Error on Input '=' (self.haskell)submitted 2 years ago * by zeltolI am studying from Learn You a Haskell for Greater Good. Not the answer you're looking for? tr command has no effect when used in $() and saved in a variable Why not to cut into the meat when scoring duck breasts? In any case, it's just a matter of style, so YMMV.

What to do with my pre-teen daughter who has been out of control since a severe accident? Haskell If Then Else share|improve this answer edited Jan 9 '14 at 6:44 answered Jan 9 '14 at 6:38 Sibi 23.2k64797 add a comment| up vote -1 down vote then let o = zipWith (+) In the example my prof gave us, he wants the states to be Chars and the path labels to be either 0 or 1. http://stackoverflow.com/questions/16846584/parse-error-on-input-in-haskell-if-then-else-conditional A word generalizing over inputs and outputs (of a system) What does 'tirar los tejos' mean?

Browse other questions tagged haskell conditional parse-error or ask your own question. Main> putStr (hanoi_shower (hanoi 1 2 3 2)) Move 1 to 2. I was making a stupid mistake; I was trying to define the variable types that were in a type signature in the actual function definition.Working code:Code: Select all-- Adds a new Not the answer you're looking for?

Haskell If Then Else

For that reason, you can't omit the else, much in the same way that you can't when using the ternary if operator (conditon ? https://wiki.haskell.org/Common_Misunderstandings x x) has a type, then is the type system inconsistent? Parse Error On Input Haskell more stack exchange communities company blog Stack Exchange Inbox Reputation and Badges sign up log in tour help Tour Start here for a quick overview of the site Help Center Detailed Haskell Let As you do not want antyhing to actually happen if the condition is false, the most immediate solution is using the dummy IO () value, return (): palin :: IO ()

This means you have to be more disciplined with tabs vs. navigate here For example a missing else clause now prints "parse error in if statement: else clause empty" instead of "parse error (possibly incorrect indentation or mismatched brackets)". Success! View More Recalll - Medium for programmers.

As I was typing that, I realized I forgot to add a comma after insertVertex when I commented out the other functions I need to implement. Here, one coder attempted to write a function hanoi to solve the Towers of Hanoi problem, but to code it so that each tower could be named polymorphically, using, for example, spaces. http://back2cloud.com/parse-error/parse-error-on-input-where-haskell.php Generating Pythagorean triples below an upper bound sort command : -g versus -n flag Human vs apes: What advantages do humans have over apes?

palin :: IO () palin = do line <- getLine putStr line --Probably better to use putStrLn? View More at http://stackoverflow.com/questions/16846584/parse-error-on-input-... Oh and one other thing, welcome to SO! –S.R.I Jan 9 '14 at 6:28 add a comment| 3 Answers 3 active oldest votes up vote 2 down vote You seem to

You have two different definitions for fractionalKnapsack, each taking a different number of arguments, clearly that causes the compiler some trouble.

I still write all my Haskell code with quite a few tabs, but you must respect the layout rules. Even conditional statement is expression as well as putStr "hi" and they have their (return) values. if True then putStr line else putStr "hi" --Also consider putStrLn here? Why shared_timed_mutex is defined in c++14, but shared_mutex in c++17?

I'm getting what I think is a syntax error, but I've gone through it a few times and can't see any mistakes. How to improve this plot? Thanks! this contact form While it's probably > possible to compile this code by making sure that the extension isn't > active (for instance, using ghc instead of ghci), it is probably a > better

Which is to say that /u/AlmostProductive is probably right and it's an indentation problem. Top dosboot Posts: 143 Joined: Sun Jul 01, 2007 5:26 am UTC Re: Haskell - "Parse error on input" Quote Postby dosboot » Mon Jan 26, 2009 3:52 am UTC v perfect explanation! –DemianArdus May 5 '14 at 2:10 add a comment| up vote 2 down vote You're missing an else. more stack exchange communities company blog Stack Exchange Inbox Reputation and Badges sign up log in tour help Tour Start here for a quick overview of the site Help Center Detailed

In Haskell everything after = is an expression, and expressions usually have values. computeKnapsack (sort fracList) computeKnapsack $ sort fracList computeKnapsack sort(fracList) computeKnapsack sort (fracList) computeKnapsack sort fracList sort fracList Haskell, parse error in input 'if' - Stack Overflow View More at http://stackoverflow.com/questions/11814525/haskell-parse-error-i... Top stone915 Posts: 42 Joined: Wed Jan 07, 2009 4:31 am UTC Re: Haskell - "Parse error on input" Quote Postby stone915 » Mon Jan 26, 2009 4:18 am UTC dosboot It's unlikely that your text editor and GHC agree on how many spaces each tab should count as, so if you mix tabs and spaces things that look fine to you

foo : bar) in other languages. What exact message are you getting? permalinkembedsaveparentgive gold[–]chrisdoner 2 points3 points4 points 2 years ago(0 children)A stranger offered me a tab once, I just said “no.” permalinkembedsaveparentgive gold[–][deleted] 1 point2 points3 points 1 year ago(0 children)Just came here to say thank I'm working on the second part of the assignment.

Any help appreciated. Although not entirely satisfactory, this commits therefore reverts those parser changes. Move 'a' to 'c'. comment:5 Changed 15 months ago by thomie Keywords newcomer added comment:6 Changed 15 months ago by thomie Keywords newcomer removed I'm inclined to just the delete the parser changes from ​Phab:D201.

This means the below signature is invalid: ghci> map floor [1,2,3,4] :: [Float] and should instead be: ghci> map floor ([1,2,3,4] :: [Float]) or alternatively put the type signature on one AAA+BBB+CCC+DDD=ABCD Why not to cut into the meat when scoring duck breasts? permalinkembedsaveparentgive gold[–][deleted] 0 points1 point2 points 2 years ago(1 child)(LYAH should drop these pseudoscientific examples, or clearly mark them as such.) permalinkembedsave[–]MrPopinjay 0 points1 point2 points 2 years ago(0 children)What do you mean? Daily news and info about all things Haskell related: practical stuff, theory, types, libraries, jobs, patches, releases, events and conferences and more...

something ... } | 'if' exp optSemi 'then' exp optSemi error {% ... Top stone915 Posts: 42 Joined: Wed Jan 07, 2009 4:31 am UTC Re: Haskell - "Parse error on input" Quote Postby stone915 » Mon Jan 26, 2009 5:40 am UTC Here's For that reason, you can't omit the else, much in the same way that you can't when using the ternary if operator (conditon ? Join them; it only takes a minute: Sign up “parse error on input” in Haskell if-then-else conditional up vote 2 down vote favorite The following do block throws the error "parse