more tolerant 'do'

gistfile1.hs

{-#LANGUAGE RebindableSyntax, RecordWildCards, CPP, OverloadedStrings #-}  

import Data.Monoid
import Prelude
import Control.Monad
import Data.String
import Text.Blaze.Html5 as H
import Text.Blaze.Html5.Attributes as A
import qualified Text.Blaze as B

data Person = Person {name :: String, age :: Int}

greet Person{..} = do 
  let (>>) = (<>)
  "Your name is "
  name
  " and your age is "
  show age


greet2 Person{..} =  do {"Your name is "; name; " and your age is "; show age}
  where (>>) = (<>)

#define monoid let (>>) = (<>) -- yeck
greet3 Person{..} = do monoid
                       "your name is " 
                       name
                       " and your age is "
                       show age
                       
-- here the point would be to dispense with the Monad instance
-- everyone whines about:
#define blaze let (>>) = (<>)
numbers n = do blaze 
               docTypeHtml $ do 
                     H.head $ do
                          H.title "Natural numbers"
                     body $ do
                          p "A list of natural numbers:"
                          ul $ foldMap (li . toHtml) [1 .. n] 
  

#define infix(x) let (>>) = (x)

aa n = do infix(+)
          13
          n
          3 * n
          foldr (*) 1 $ [1..n] ++ [5..6]

bb f g x = do infix($)
              f
              g
              x

mklist = do infix(:)
            sum [1..20]
            product [2..5]
            foldr (+) 0 [2..4]
            []