[](https://travis-ci.org/cartazio/strict-identity)
#About
strict-identity package is meant to make writing nested strict let
expression heavy code a bit more pleasant, for all those High Performance
Haskell lib authors out there.
A simple example of the strict identity monad in action (and working wonderfully)
is the following bit fiddling code, which generates C competitive assembly
on both major GHC backends, -fasm and -fllvm
```haskell
(>>) = unsafeShiftR
(<<) = unsafeShiftL
outerShuffle64A :: Word -> Word
outerShuffle64A !x =
runStrictIdentity $! do
x <- return $! ((x .&. 0x00000000FFFF0000) << 16 )
.|. ((x>>16) .&. 0x00000000FFFF0000) .|. (x .&. 0xFFFF00000000FFFF)
x <- return $! ((x .&. 0x0000FF000000FF00 ) << 8 )
.|. (x >> 8) .&. 0x0000FF000000FF00 .|. (x .&. 0xFF0000FFFF0000FF)
x<- return $! (( x .&. 0x00F000F000F000F0 ) << 4 )
.|. (x >> 4) .&. 0x00F000F000F000F0 .|. (x .&. 0xF00FF00FF00FF00F )
x<- return $!((x .&. 0x0C0C0C0C0C0C0C0C )<< 2 )
.|. (x >> 2) .&. 0x0C0C0C0C0C0C0C0C .|.( x .&. 0xC3C3C3C3C3C3C3C3)
x<- return $! ( (x .&. 0x2222222222222222) << 1 )
.|. (x>> 1) .&. 0x2222222222222222 .|. (x .&. 0x9999999999999999)
return x
```