varreli

module ParseFull where
import Control.Applicative
import Data.Char

newtype Parser a = P (String -> [(a,String)])  

parse :: Parser a -> String -> [(a,String)]
parse (P p) inp = p inp

item :: Parser Char 

varreli

module ShowExpression where

data Op = Add | Sub | Mul | Div 

instance Show Op where
  show Add = "+"
  show Sub = "-"
  show Mul = "*"
  show Div = "/"

varreli

import Debug.Trace

subs :: [a] -> [[a]]
subs []     = [[]]
subs (x:xs) = yss ++ map (x:) yss
  where yss = subs xs

interleave :: a -> [a] -> [[a]]
interleave x []     = [[x]]
interleave x (y:ys) = (x:y:ys) : map (y:) (interleave x ys)

varreli

module ShowExpression where

data Op = Add | Sub | Mul | Div 

instance Show Op where
  show Add = "+"
  show Sub = "-"
  show Mul = "*"
  show Div = "/"

varreli

import ShowExpression


subs :: [a] -> [[a]]
subs []     = [[]]
subs (x:xs) = yss ++ map (x:) yss
  where yss = subs xs

interleave :: a -> [a] -> [[a]]
interleave x []     = [[x]]

varreli

split :: [a] -> [([a], [a])]
split []     = []
split [_]    = []
split (x:xs) = ([x], xs) : [(x:ls, rs) | (ls, rs) <- split xs]

-- auxillary function combine in exprs:

combine :: Expr -> Expr -> [Expr]
combine l r = [App o l r | o <- ops]

varreli

~/haskell/hutton]
 $ ls
001_math             28_and_all.hs      59_chapt7.hs
002_notes            29_recurse.hs      59_chapt7i.hs
01_qsort.hs          30_merge.hs        60_redefines.hs
02_last.hs           31_mergeSample.hs  61_iterate.hs
03_init.hs           32_mSort.hs        62_parity.hs
04_abs.hs            33_core.hs         63_parity2.hs
05_twice.hs          34_core.hs         64_altMap.hs
06_patMatch.hs       35_basicMap.hs     65_luhn.hs

varreli

λ > :l 75_taut.hs 
[1 of 1] Compiling Main             ( 75_taut.hs, interpreted )

75_taut.hs:2:1: error:
    Failed to load interface for ‘Propositions’
    Use -v to see a list of the files searched for.
Failed, modules loaded: none.
 λ > 

varreli

I'm running $ stack build primality now , and getting the same very slow process that I got for $ stack new primality:

~/haskell $ stack new primality
Downloading template "new-template" to create project "primality" in primality/ ...

The following parameters were needed by the template but not provided: 
author-email, author-name, category, copyright, github-username
You can provide them in /home/john/.stack/config.yaml, like this:
templates:
  params:

varreli

~ $ sudo apt-get install vim
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Suggested packages:
  vim-doc vim-scripts
The following NEW packages will be installed:
  vim
0 upgraded, 1 newly installed, 0 to remove and 316 not upgraded.
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