[Haskell-cafe] On syntactic sugar

[Alfonso Acosta]

2008/5/12 Lauri Oksanen <lassoken at gmail.com>:
> Hi,
>
> I'm writing my first real Haskell program and I came up with the following
> code snippet.
>
> ---
> let x' = x \+ dist \* dir
>     nx' =  normal geometry
>     wi = (-1) \* dir
>     in do
>          (p, wo) <- brdfCosSampling reflector nx' wi
>         let color' = p \** color
>             q = min 1 (scalarContribution p)
>             in do
>                 sampler <- biasedCoinSampler q
>                          (radianceSampler surfaces x' wo (q \* color'))
>                         (terminalRadianceSampler surfaces x' nx' ((1-q) \*
> color'))
>                 sampler

Do-notation already offers what you want. Try this out:


 do let x' = x \+ dist \* dir
           nx' =  normal geometry
           wi = (-1) \* dir
      (p, wo) <- brdfCosSampling reflector nx' wi
      let color' = p \** color
           q = min 1 (scalarContribution p)
       sampler <- biasedCoinSampler q
                          (radianceSampler surfaces x' wo (q \* color'))
                         (terminalRadianceSampler surfaces x' nx'
((1-q) \* color'))
       sampler