Peter Kourzanov <[email protected]> writes: >> > * matching numbers: we need to use (=) to match them, not equal? >> > (or eqv? and eq?) >> >> Do we? :) >> > > Typing. A good example: 42+0.0 should match both 42.0 and 42.
Note that (R6RS) syntax-case is defined to use equal? for literal
pattern data:
* P is a pattern datum (any nonlist, nonvector, nonsymbol datum) and F is
equal to P in the sense of the equal? procedure.
which reduces to `=' for two exact or two inexact values, but #f
otherwise. R6RS also notes that `=' is not required to be reliable for
inexact numbers.
The Wright pattern-matching library uses equal? for literal pattern
data, as well, as do the Racket, Chicken, and match.scm implementations.
This has the advantage of providing a single rule for literal data.
What is the use case for special-casing numbers?
--
Jim Wise
[email protected]
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