CODEWITHSUNDEEP
haskellindentation
Andreas Sjöström
Andreas Sjöström

Reputation: 43

Haskell, possible indentation error that I can't get rid of

I have a problem and cannot find out what it is. I have reindented again over and over, but cannot find the solution. Is there something else this can be dependent on?

Code:

type Triple = (Prime, Quot, Gen)

correctness :: Triple -> Bool
correctness (p,q,g) = prime && pLength && qLength && divisor && orderq
           where prime   = probablyPrime n 5
                 qLength = q < 2^1024
                 pLength = p < 2^160
                 divisor = (p-1 `mod` q) == 0
                 orderq  = (g^q mod p == 1) && (g > 1)

Error Message (line 94 corresponds to "correctness :: Triple -> Bool"):

crypt.hs:94:0: parse error (possibly incorrect indentation)

EDIT: I solved the problem. The problem was a syntax error in an above function. I had otherwise m_ify m*2 instead of otherwise = m_ify m*2

Upvotes: 1

Views: 1351

Answers (3)

luqui
luqui

Reputation: 60513

Worksforme, jumps right into the type errors.

Is line 92 the 

type Triple = (Prime, Quot, Gen)

line, or did you move that from somewhere else? Sometimes errors can show up with a line number later than where they actually occur. I would check for mismatched parentheses above line 92 (probably nearby).

And on some occasions an invisible unicode character seems to sneak into my code. Retyping has occasionally worked.

Upvotes: 1

Travis Brown
Travis Brown

Reputation: 139058

You might just need to add backticks around the mod in the final line. This wouldn't cause the indentation error you report, but the following compiles for me:

n = undefined
probablyPrime = undefined
type Prime = Int
type Quot = Int
type Gen = Int

type Triple = (Prime, Quot, Gen)

correctness :: Triple -> Bool
correctness (p,q,g) = prime && pLength && qLength && divisor && orderq
           where prime   = probablyPrime n 5
                 qLength = q < 2^1024
                 pLength = p < 2^160
                 divisor = (p-1 `mod` q) == 0
                 orderq  = (g^q `mod` p == 1) && (g > 1)

The only change here (apart from the first five lines) is in the last line.

Upvotes: 1

0xAX
0xAX

Reputation: 21837

Try:

type Triple = (Prime, Quot, Gen)

correctness :: Triple -> Bool
correctness (p,q,g) = prime && pLength && qLength && divisor && orderq
           where 
              prime   = probablyPrime n 5
              qLength = q < 2^1024
              pLength = p < 2^160
              divisor = (p-1 `mod` q) == 0
              orderq  = (g^q mod p == 1) && (g > 1)

Read - http://www.haskell.org/onlinereport/syntax-iso.html - 9.3 Layout

Upvotes: 0

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