On 2020-11-16 08:54, Glenn Linderman wrote:
On 11/15/2020 11:18 PM, Stephen J. Turnbull wrote:
Jim J. Jewett writes:
> What advantage can there be in re-using syntax to mean something
> opposite to what it normally does?
In math, it allows us to write "solve c = f(x) for x". That doesn't
mean "bind c to the value f(x)", it means exactly the opposite. No
problem here, I suppose. So
match p:
case Point(x=a, y=b):
is a way of saying "solve p = Point(x=a, y=b) for a and b".
I understand your distaste for this syntax, but I see no problem
in principle. It's a problem of programmer habits and the evident
inconsistency with forms like "case Point(x=1, y=2)". This is
especially true when a or b is already bound.
Indeed. Mathematics never came up with separate symbols for equality and
assignment. Neither did early programming languages. That was a source
of confusion for many programmers.
[snip]
Fortran (1954) used '=' for assignment and '.EQ.' for equality.
Algol (1958) used ':=' for assignment and '=' for equality.
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