Re: backslashes within quotes
I agree that backslash string wrapping is obscure.
I do use it a lot, but I would not be sad to see it go.
The same is true for \a, \b, \f, \v, \EM, \DC1, etc.
We do need \, though.
On Tue, Oct 2, 2012 at 10:17 PM, Evan Laforge qdun...@gmail.com wrote:
The backslash string wrapping feature is a fairly obscure part of
haskell syntax, and some tools don't handle it properly (e.g. the
built in 'lex' function won't lex such strings properly). It's also
not as useful as e.g. python's triple quotes, because you have to
suffix and prefix every line with a backslash. As long as you are
have to add suffixes and prefixes (i.e. straight cut and paste no
longer works), you might as well write it out with (++). In other
words, as long as you're applying ('\\':) . (++\\) you might as well
apply (++ \++) . (++\). And it seems to me that string
literal ++ another string is an easy thing for a compiler to
optimize, ghc-core says ghc unsurprisingly has no trouble with it.
So it's probably not helpful for performance. IMO it's not very
useful for it's intended purpose (embedding multiline strings) because
of the \s everywhere. It doesn't seem very widely used, and it adds a
little bit of a hassle to parsing. And 'lex' doesn't support it.
Any interest in getting rid of it?
I would actually be in favor of triple quotes (yeah, I know it can be
done with quasi-quotes, but still...), but that's a different issue.
Also, it's hardly a big deal, but do we really need \a, \b, \f, and
\v? The one time I used one (it was \v) it was a typo and I would
have preferred the parse error, instead I got weird output that I
didn't notice for a long time. If I really want to, say, ring the
terminal bell or do a vertical tab or perhaps send a telegraph, I
would be using some library that handles terminal type stuff in a
higher level way. Similarly, the \EM, \DC1, etc. codes are probably
not pulling their weight. The '70s were 40 years ago! And there's
that weird \ thing. Surely cursor control library authors have
better ways to construct their magic codes.
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Re: backslashes within quotes
On Fri, Oct 5, 2012 at 8:01 AM, Lennart Augustsson lenn...@augustsson.net wrote: I agree that backslash string wrapping is obscure. I do use it a lot, but I would not be sad to see it go. On Fri, Oct 5, 2012 at 9:50 AM, Henrik Nilsson henrik.nils...@nottingham.ac.uk wrote: I find it quite neat, also use it a lot, and would be sad to see it go. It is also a good feature for automatic formatting of code to a specific width. But what about just replacing those \s with ++? It's true it's a few more characters, but is it really that much more work? I actually just used the \s recently, and being 3 characters shorter is a bit nicer, but not that much nicer. And it messed up my simplistic syntax highlighting. However, I did notice that given OverloadedStrings, 'hello there :: Text' does not get optimized to 'Text.pack hello there', but for all I know the complicated thing it emits is just as efficient. The same is true for \a, \b, \f, \v, \EM, \DC1, etc. We do need \, though. What is \ used for? I never knew it existed until I reread that bit of the report, and couldn't figure out what it was for. I'm assuming that only terminal manipulation stuff needs those things, and that you would generally not want to write it inline, but write something like 'ringyDingy I'm going to nag and bell at you!', and ringyDingy is just as happy to build the bell with Char.chr. I guess this is pretty much bike-sheddery so I'll leave it at this, but it seems like the darker corners should be subject to some spring cleaning every 10 years or so... ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
Re: backslashes within quotes
On Friday, 5 October 2012 at 15:34, Evan Laforge wrote: On Fri, Oct 5, 2012 at 9:50 AM, Henrik Nilsson henrik.nils...@nottingham.ac.uk (mailto:henrik.nils...@nottingham.ac.uk) wrote: The same is true for \a, \b, \f, \v, \EM, \DC1, etc. We do need \, though. What is \ used for? I never knew it existed until I reread that bit of the report, and couldn't figure out what it was for. There's a conflict between \SOA and \SO followed by A, which is resolved by making the latter \SO\A. -- brandon s allbery kf8nh sine nomine associates allber...@gmail.com ballb...@sinenomine.net unix/linux, openafs, kerberos, infrastructure http://sinenomine.net Sent with Sparrow (http://www.sparrowmailapp.com/?sig) ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
Re: backslashes within quotes
\xe\x1 is unambiguous. There are two things wrong with this solution: (1) It descends to another level of discourse--binary encoding of characters. (2) It does not actually eliminate the need for \. Consider the string \SOH1. It cannot be written \x11, or even \x011. Doug McIlroy ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
