Rules for takeWhile and dropWhile

[Bodigrim]

Closes #176.

[sjakobi]

LGTM.

While reviewing this, I was looking for example incantations of break[Byte] and span[Byte], but couldn't find any in the documentation. Does this sound worth fixing/tracking?

[Bodigrim]

@sjakobi do you mean bytestring documentation?

bytestring/Data/ByteString.hs

Lines 879 to 884 in 14db3e4

	{-# RULES
	"ByteString specialise break (x ==)" forall x.
	break (x `eqWord8`) = breakByte x
	"ByteString specialise break (== x)" forall x.
	break (`eqWord8` x) = breakByte x
	#-}

bytestring/Data/ByteString.hs

Lines 942 to 947 in 14db3e4

	{-# RULES
	"ByteString specialise span (x ==)" forall x.
	span (x `eqWord8`) = spanByte x
	"ByteString specialise span (== x)" forall x.
	span (`eqWord8` x) = spanByte x
	#-}

[sjakobi]

@sjakobi do you mean bytestring documentation?

Yeah. I realized too late that I could simply look at base's documentation of break and span for [].

[Bodigrim]

OK, I decided to grab an opportunity to improve documentation for this functions as well.

[vdukhovni]

Some nits in the docs

[Bodigrim]

@vdukhovni sorry, I'm not a native speaker, but what is wrong with "a {part/suffix/prefix} of xs, elements of which bla-bla-bla"?

[vdukhovni]

@vdukhovni sorry, I'm not a native speaker, but what is wrong with "a {part/suffix/prefix} of xs, elements of which bla-bla-bla"?

As an inserted clause, "elements of which satisfy ...", to me sounds closer to the kind of language one might find in legal contracts, than in day-to-day English... It might be best in the positive case to write:

a {part/suffix/prefix} of xs, whose elements all bla-bla-bla,

and in the negative case

a {part/suffix/prefix} of xs, none of whose elements bla-bla-bla

With the only possibly confusing case being with "break" which returns both parts, and so then adds ", and the rest ...", with some confusion about what the "and ..." is associated with.

That's part of the reason I wanted to eliminated the inserted clause and go with " a ... of xs all/none of whose elements ..., and the rest ...".

What do you think?

[Bodigrim]

@vdukhovni how is it looking now?

[vdukhovni]

@vdukhovni how is it looking now?

Better. Thanks.