On Tuesday, 7 March 2017 at 15:34:54 UTC, ketmar wrote:
Jack Stouffer wrote:
On Tuesday, 7 March 2017 at 15:05:45 UTC, ketmar wrote:
only for primitive types, sadly.
void main () {
Object a, b;
a == b;
}
oops. no more error messages. yes, i know that this invokes
`opEquals()`, and `opEquals()` can have side-effects. but
what are the chances of writing such code *intentionally*?
Hmm, I guess the compiler can (and should) output an error
message if it knows that opEquals is `pure`.
https://issues.dlang.org/show_bug.cgi?id=17245
yet Object's `opEquals()` is not pure (and it cannot be, to
allow non-pure overloads). still, the code i've written has no
sense.
I'm curious. Where does it make sense for opEquals to be
non-pure? Likewise opCmp, etc.
Maybe we want to support weird DSLs, where operators are reused
with very different semantics? For example, the pyparsing parser
generator allows you to write a grammar like [0] this:
exp << Group(lparen + op + (number | exp) + (number | exp) +
rparen)
[0]
http://pyparsing.wikispaces.com/file/view/pycalc.py/480674428/pycalc.py
