[erlang-questions] atoms with newlines
Richard A. O'Keefe
Wed Feb 26 21:30:22 CET 2014
On 26/02/2014, at 10:56 PM, Valentin Micic wrote:
> If this is *really* necessary, wouldn't it be less confusing (or even more consistent) to consider:
> 1> 'foo' \
> 1> 'bar'.
> 3> 'foo
> includes a new line -- as already does.
No, and on two grounds.
First, backslash escapes are not a special notation
confined to Erlang. They are supported in a wide
variety of languages. Not just the "usual suspects"
in the C family. There's Python, for example. And
logic programming languages and functional languages too:
>>> print "a\
ab -- Python
val it : string = "ab" -- F# and O'CAML
?- X = 'a\
X = ab. -- Prolog and Mercury
So having backslash+newline *silently accepted* and
do *exactly the opposite of what people expect* cannot
be a good thing.
We already have two ways to get a newline into an Erlang
string or atom: a bare newline or a \n escape. We really
do NOT need a third, especially one that is basically an
It would be excusable to make backslash+newline an
always-reported syntax error. People would get a nasty
surprise, but at least they wouldn't silently get the
wrong value in their program. In fact I think that
*every* \<char> combination that is not explicitly
documented should be reported as a syntax error.
Second, it is currently the case that backslash has a
special meaning in Erlang *ONLY* inside quoted literals
(counting $\t as a quoted literal). Your "less confusing
(or even more consistent)" proposal introduces a new
thing that *looks* like an operator but *isn't* one.
It is difficult to see how that is less confusing than
following common practice or more consistent with anything.
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