Avoid blank line separating code and comments in Bird style?

[Richard Eisenberg]

I think the underlying problem here is that there is a difference between "literate" comments and "normal" comments.

In a bird-style literate Haskell file, this is what I'll call a literate comment:

~~~
A line with no marker at the beginning
~~~

A normal comment is in a line of Haskell code, put with a comment indicator:

~~~
> -- This is a "normal" comment
~~~

When GHC sees a bird-style literate Haskell file, it first strips out all lines that don't begin with >. Then, it starts doing its real work, including parsing Haddock comments. So, to use a Haddock comment in a literate Haskell file, you'd need to use the "normal" comment style:

~~~
> -- | Make a numbered widget
> mkWidget :: Int -> Widget
~~~

There is no way to use Haddock markup in a "literate" comment.

But, as Mateusz points out, there may be blank lines between the Haddock comment and the thing being described:

~~~
> -- | Get the number of a widget
>
> widgetNum :: Widget -> Int
~~~

I hope this clarifies things!
Richard


On Jan 14, 2015, at 2:42 AM, sidhu1f <sidhu1f at gmail.com> wrote:

> At Wed, 14 Jan 2015 12:31:54 +0530,
> Mateusz Kowalczyk wrote:
> 
>> I imagine you're suggesting that something like
> 
>> Literate comment
>>> someCode = undefined
> 
> This (literate comment followed by code with no intervening blank
> line) is exactly what I want (regret my explanation was unclear). But
> when I try it, GHC reports the error 'unlit: Program line next to
> comment'.
> 
>> is allowed ...
> 
> As you mention above behaviour is allowed, could you let me know how
> to enable it?
> 
> Regards
> Sidhu
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