On 5/31/11 1:34 AM, Stewart Gordon wrote:
On 29/05/2011 14:03, bearophile wrote:
Stewart Gordon:
There are places where the spec fails to make a clear distinction
between illegal code and
incorrect code that the compiler may reject if it's smart enough.
In D there are pure functions, so I think it's not too much hard for
it to tell apart
when the contents of an assert() are pure or not.
My opinion is that the D compiler has to enforce purity inside
assert(), to avoid bugs.
Only if purity rules are relaxed. AIUI, one of the restrictions at the
moment is that in a pure function only immutable data can be accessed.
As long as this restriction remains in place, adding the restriction of
purity to asserts would erode their usefulness.
Stewart.
Nope, since the new, relaxed purity rules (originally proposed by Don,
IIRC) were implemented in DMD 2.050, this is no longer the case. »Weakly
pure« functions take mutable parameters and can access them (this also
applies to the hidden this reference), while »strongly pure« functions
only operate on immutable values. There is no syntactic distinction
between them, both are annotated by the »pure« keyword, it just depends
on the parameter types.
David
