[erlang-questions] extend parser to allow single quotes in variable names (or: "let's confuse the text editors!")
Sun Oct 7 23:44:45 CEST 2012
On 8/10/2012, at 5:35 AM, Motiejus Jakštys wrote:
> In Haskell you can have variable names with single quotes. Imagine for a
> moment you are in a perfect world:
> oops() ->
> A = 1024,
> A' = math:log(A) / math:log(2),
> io:format("Wow! ~p~n", [A']).
> What would you think about this extension?
I would think it was pointless.
Spot the pattern?
Haskell (or at least GHC) allows primes inside identifiers too,
but nobody seems to take advantage of that.
Consider f'x 'y'. Want to read _that_ fast?
Consider f'x' y'. Want to tell them apart fast?
SML also allows primes inside and at the end of identifiers.
This is much less of a pain in SML because SML writes
character literals as #"x" rather than 'x'.
There is historically and in good typography a clearly visible
distinction between the apostrophe and the superscript I II III
IV V: (x' is x prime; x'' is x second; x''' is x third, and
the next one is x<sup><small>IV</small></sup>, x fourth, not
x''''). It's only the limitations of old typewriters and ASCII
that lead us to confuse them. Superscript Roman numerals in
Unicode identifiers, fine; using the apostrophe as the quote
character for atoms and also in identifiers, not fine.
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