Scripts

hc compiles the file.

ghc -o $1 $1.hs

The file should be named A.hs, B.hs, C.hs, etc.

r runs the file on small input. (ex. r A) On the first (0th) attempt, omit the 2nd parameter. On subsequent attempts, add the number as the second argument. (ex. r A 1)

num=${2-"0"}
./$1 "$1-small-attempt$num.in"

rb runs the file on large input.

./$1 "$1-large.in"

Parsing

Basic types

• int
• integer
• str
• chr
• float
• double
• bool

Combinators

• emptyH = line >>: read a header, discard, and continue. (Ex. the header contains the number of test cases; a lot of the time we can safely discard.
• tupleS: take a tuple of parsers and make a parser for the tuple using spaces as the separator
• tupleL: take a tuple of parsers and make a parser for the tuple using lines as the separator
• listS: read list separated by spaces
• listL: read list separated by lines (Warning: this continues until end of file)
• readH :: (Int -> Int) -> Parser a -> Parser (Int, [a]): read a header containing an integer, and use it to determine how many times to run Parser a.
• readH_ :: (Int -> Int) -> Parser a -> Parser [a]: like readH, but don't bother outputting the integer.
• readN, readN_ are where you just use id for Int -> Int.
• readH' :: (a -> Int) -> Parser a -> Parser b -> Parser (a, [b]) is the more complicated version where you give a parser for the header, and extract a length from it.

Example (2015-2C):

To read

6
2
he loves to eat baguettes
il aime manger des baguettes
4
a b c d e
f g h i j
a b c i j
f g h d e
4
...

use

type Input = [[S]]
type Output = I

input :: String -> [Input]
input = justParse (emptyH $ listL $ readN_ $ listS str)