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Parse Error On Input Where Haskell

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None of the tutorials mentioned ‘let' and I couldn't figure out what was happening. 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 Having reinstalled that, however, I still had the same problem. Any ideas on what could be producing this error messageCode: Select allFA.hs:21:0:
Occurs check: cannot construct the infinite type: a = b -> a
When generalising the Source

My job is to use the Digraph module to create a finite automaton. How to improve this plot? I've tried removing the if-then-else portion since my prof told us it was optional and using (graph Char Int) instead of graph as a parameter, but neither worked. I don't think I'm going to use too many of your modifications, partly because it involves code we haven't covered in class yet and partly because I'd rather turn in code you could try here

Haskell Parse Error Possibly Incorrect Indentation

Be Sociable, Share! Can an irreducible representation have a zero character? I haven't written that part yet, I'm waiting until I can get the function itself to work. What exact message are you getting?Code: Select allps2.hs:9:16: parse error on input `empty'
EDIT: I counted the lines, and line 16 isn't the definition of the empty function, it's this:Code: Select

Join them; it only takes a minute: Sign up Haskell parser error in where clause up vote 4 down vote favorite What is wrong with rs definition in first where section? The error message is [1 of 1] Compiling Main ( pelindrome.hs, interpreted ) pelindrome.hs:5:8: parse error on input `rs' syntax haskell share|improve this question edited Apr 24 '12 at 14:26 Riccardo share|improve this answer answered Jan 6 '09 at 18:17 Hynek -Pichi- Vychodil 19.7k33161 I thought (++) was defined as (++) = flip $ foldr (:) - that's how I Haskell Parse Error On Input Function So the edge ('a','b',1) means that when given the input 1, move from state 'a' to state 'b'.

Sound and Fury News & Articles Serious Business XKCD Meetups General Numberologics, Alchemy, Linguinomics, and other Academiology Mathematics Science Fictional Science Language/Linguistics Parse Error On Input =' Ghci Whenever I try to compile the code, I get this error message.Code: Select allps2.hs:4:16: parse error on input `insertVertex'
Can anyone tell me what this message means? I'm currently trying to write a function (stepDFA) that, when given an automaton, a state name, and an input symbol, will return the state reachable from the given state by using https://wiki.haskell.org/Common_Misunderstandings Top Berengal Superabacus Mystic of the First Rank Posts: 2707 Joined: Thu May 24, 2007 5:51 am UTC Location: Bergen, Norway Contact: Contact Berengal WLM Re: Haskell - "Parse error on

Output the Hebrew alphabet DDoS ignorant newbie question: Why not block originating IP addresses? Haskell Parse Error On Input Module In the example my prof gave us, he wants the states to be Chars and the path labels to be either 0 or 1. I have a couple of the functions written, but I'm encountering some difficulty writing the function to add a vertex with an empty adjacency list to the graph. What exact message are you getting?

Parse Error On Input =' Ghci

I was also trying it on two separate lines which works in .hs files but not in ghci. The following code gives the same error listed above. Haskell Parse Error Possibly Incorrect Indentation Erlang). Parse Error In Pattern Haskell are the integers modulo 4 a field?

I think you mean to add another argument to that, most likely "input". http://kiloubox.com/parse-error/parse-error-haskell.html I'm not a haskell guy). In the first case each step of the computation is evaluating something to the effect of False || 'rest' where 'rest' is a tail recursive call to foldl'. I was given a template with type declarations and function type signatures and was told to implement the functions. Haskell Parse Error On Input Let

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 4:58 am UTC Awesome, hacker module Main where main = let x = 1;   y = 2;   z = 3;   in putStrLn $ "X = " ++ show x ++ "nY = asked 7 years ago viewed 7218 times active 4 years ago Related 494Haskell: difference between . (dot) and $ (dollar sign)172What does the exclamation mark mean in a Haskell declaration?761Getting started have a peek here Try this in ghci Code: Select allPrelude> let ff = take 1000000 (repeat False)
Prelude> import Data.List

There was also a argument missing for the call to rev (an empty list): palindrome :: [a] -> [a] palindrome xs = con xs rs where con a b = rev Haskell Parse Error On Input If Any ideas on what's causing this, or an explanation as to what a parse error is? 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 5:24 am UTC Berengal

My previous version is way how to write it in non lazy functional or logical languages in tail call fashion (e.g.

It is weird rule. –Hynek -Pichi- Vychodil Jan 5 '09 at 11:52 Not weird: same syntactic level -> same indentation –Svante Jan 5 '09 at 12:04 you I'm working on the second part of the assignment. Mark Needham @crasshopper:disqus I'm not sure I understand what you mean. Parse Error On Input Arrow Anyway, have fun!

Why don't cameras offer more than 3 colour channels? (Or do they?) Digital Alarm Clock What's difference between these two sentences? 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 Why does a full moon seem uniformly bright from earth, shouldn't it be dimmer at the "border"? http://kiloubox.com/parse-error/parse-error-on-input-import-haskell.html Thanks a lot!

Basically, it will hold a directed graph, an initial value, and a list of possible final values. I did replace the concatenation with (:) for efficiency. Why do jet engines smoke? Found an article about the different types of folds if anyone else is interested.http://haskell.org/haskellwiki/Foldr_Foldl_Foldl' Top stone915 Posts: 42 Joined: Wed Jan 07, 2009 4:31 am UTC Re: Haskell - "Parse error

Select Only Printed Out Cells Why did they bring C3PO to Jabba's palace and other dangerous missions? Line 9, character 16 is the beginning of the declaration of empty in the module interface. Thanks!Code: Select all-- CS 8 Problem Set 2
-- FA.hs
-- Author: Matt Stone

module FA where

import Digraph

data Automaton a b = FA {graph :: Digraph module Main where main = let x = 1 y = 2 z = 3 in putStrLn $ "X = " ++ show x ++ "\nY = " ++ show y

Longest "De Bruijn phrase" in English Why would breathing pure oxygen be a bad idea? 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 4:24 am UTC You However, I do appreciate the recommendations. 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.

Re: Haskell - "Parse error on input" Quote Postby Qoppa » Mon Jan 26, 2009 5:36 am UTC line:character#, not the other way around. I think that's the right version. Fixed. Does the code terminate?

If I try this it seems ok: let addThree :: Int -> Int -> Int -> Int ; addThree x y z = x + y + z isomorphisms I was Thanks guys.Code: Select all-- CS 8 Problem Set 2
-- Author: Matt Stone

-- A module for creating and handling directed graphs

module Digraph (AdjList, Digraph, Edge,
Upper bounds for regulators of real quadratic fields Absolute value of polynomial Why don't browser DNS caches mitigate DDOS attacks on DNS providers? Thanks!Code: Select all-- A module for creating and handling directed graphs

module Digraph (AdjList, Digraph, Edge, v, e
insertVertex, insertEdge, makeDigraph, getAdj,

There's also a standard function for what you are trying to do.Made some changes:Code: Select all-- A module for creating and handling directed graphs

module Digraph where --my 2 cents: 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