chrisdone

Typing Haskell in Haskell

MARK P. JONES

Pacific Software Research Center

Department of Computer Science and Engineering

Oregon Graduate Institute of Science and Technology

andrejbauer

A bijection between numbers and pairs of numbers

Every once in a while I am faced with someone who denies that the rational numbers (or fractions, or pairs of integers) can be put into a bijective correspondence with natural numbers. To deal with the situation, I coded up the bijection. So now I can just say: "Really? Interesting. Please provide a pair of numbers (i,j) which is not enumerated by f, as defined in my gist." I am still waiting for a valid counter-example.

Anyhow, here is a demo of f and g at work. I am using the Python version, but a Haskell variant is included as well.

The 100-th pair is:

>>> f(100)

(10, 4)

mxswd

{-# LANGUAGE DataKinds, TemplateHaskell, TypeFamilies, QuasiQuotes #-}
import TICTACTOE

game :: ([tq| x o x
              o o x
              ☐ ☐ x |])
game = (?)

simonmichael

[alias]
  l    = log -10 --pretty=tformat:'%C(yellow)%ad %Cred%h%C(bold blue)%d%Creset %s' --date=short
  l2   = log -10 --pretty=tformat:'%C(yellow)%ad %Cred%h%C(bold blue)%d%Creset %s %Cgreen(%an)%Creset' --date=short
  l3   = log -10 --pretty=tformat:'%Cred%h%C(bold blue)%d%Creset %s %C(yellow)%cr %Cgreen%an%Creset' --date=relative
  l4   = log -10 --pretty=tformat:'%Cred%h %C(yellow)%ad %Cgreen%an%C(bold blue)%d %Creset%s' --date=short
  lg   = log -10 --graph --pretty=tformat:'%C(yellow)%ad %Cred%h%C(bold blue)%d%Creset %s' --date=short
  lg2  = log -10 --graph --pretty=tformat:'%C(yellow)%ad %Cred%h%C(bold blue)%d%Creset %s %Cgreen(%an)%Creset' --date=short
  lg3  = log -10 --graph --pretty=tformat:'%Cred%h%C(bold blue)%d%Creset %s %C(yellow)%cr %Cgreen%an%Creset' --date=relative
  lg4  = log -10 --graph --pretty=tformat:'%Cred%h %C(yellow)%ad %Cgreen%an%C(bold blue)%d %Creset%s' --date=short
  s    = status -sb

hdgarrood

{-# LANGUAGE OverloadedStrings #-}

import Control.Monad (forM_)
import Data.Text.Lazy (Text)
import qualified Data.Text.Lazy as T
import qualified Data.Text.Lazy.Encoding as T
import qualified Data.ByteString as BS
import qualified Data.ByteString.Lazy as BSL
import qualified Blaze.ByteString.Builder as B

mzero

#!/bin/sh

inPreprocessorMode () {
    hasE=0
    hasU=0
    hasT=0
    for arg in "$@"
    do
        if [ 'x-E' = "x$arg" ];             then hasE=1; fi
        if [ 'x-undef' = "x$arg" ];         then hasU=1; fi

cartazio

PSA :

just use GHC for OSX https://ghcformacosx.github.io

the rest of these directions are preserved for historical purposes

TLDR version, if you have homebrew

xcode-select --install ; brew tap homebrew/versions ;   brew tap homebrew/dupes \

kolen

singpolyma

-- | Simple in-process key/value cache
--
-- Of course, for really simple stuff you could probably use unsafeInterleaveIO
module Cache (Cache, newCache, fromCache) where

import Control.Monad (void)

-- Could also use STM instead
import Control.Concurrent (forkIO, Chan, newChan, readChan, writeChan, MVar, newEmptyMVar, putMVar, takeMVar)

MasseR

{-# Language GeneralizedNewtypeDeriving #-}
{-# Language OverloadedStrings #-}
import Data.Monoid
import Text.Blaze.Html.Renderer.Text
import qualified Text.Blaze.Html5 as H
import qualified Text.Blaze.Html5.Attributes as A
import Text.Blaze.Html ((!), Html)
import Control.Monad.Writer
import Control.Monad.Identity