[Haskell] Re: Use of tab characters in indentation-sensitive code
ronan at ninebynine.org
Mon Jan 26 03:53:08 EST 2004
I support the idea that somthing should be done. I would like to suggest
that the compiler references an environment variable to determine how many
spaces a tab represents. I realise that this would cause the same code to
run on some systems and fail on others, but it would allow a developer to
set up a comfortable working system without tab characters ruining the
logic of a program.
On Sat, 24 Jan 2004 18:29:46 +0100, Wolfgang Thaller
<wolfgang.thaller at gmx.net> wrote:
> Graham Klyne wrote:
>> I think that compilers should issue a warning when indentation that
>> determines the scope of a construct is found to contain tab characters.
> I'd say, when it "is found to contain a mixture of tab and space
> I have successfully written a lot of Haskell code that uses tabs
> *exclusively* - in that case, the meaning of the program *doesn't*
> depend on how the tab characters are interpreted.
> IMHO, there should only be warnings about tabs when their size makes a
> difference to the meaning of the program, as shown in the examples below:
> <spaces>x = 1
> <TAB--->y = 1 -- warning
> <TAB--->x = 1 -- OK
> <TAB--->y = 2 -- OK
> <spaces>z = 3 -- warning
> a = let x = 1
> y = 2 -- OK
> in ...
> b = let x = 1
> <TAB--->y = 2 -- warning
> in ...
> There are many editors that automatically mix tabs and spaces in
> indentation (and I don't like that - what's it good for?), but some
> people will certainly want to continue to use them, so I'm not sure if
> adding warnings like these would be acceptable to them.
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