On Thursday, 14 February 2013 at 20:01:37 UTC, Jacob Carlborg
wrote:
On 2013-02-14 13:42, Andrei Alexandrescu wrote:
I understand. Adding functions such as the negation of empty
becomes a
judgment call.
Phobos does have quite a few simple functions that could be
easily
achieved through expression composition (e.g. trim) or
statement
composition (e.g. enforce). So again it's all a matter of
judgment.
Walter and I don't consider the negation of empty as useful
enough to
receive a name.
How about this, I have another similar function that might be
useful in Phobos as well.
"isBlank" and "isPresent". "isPresent" is just the opposite of
"isBlank".
But "present" and "blank" aren't opposites in English.
"isNonBlank" or "isNotBlank" are opposites of "isBlank", but
"isPresent" would be the opposite of "isAbsent." It seems almost
meaningless in the context of a string predicate --- If I saw it
in code, I would guess it meant "not a null reference."
Similarly with "any" vs. "empty." I would think that "any" is
synonymous with "some" and therefore should be the opposite of
either "none" or "all" (leaning toward "all," given the
commonality of some/all predicates in other languages, and the
exists/forall concepts in predicate logic).
Regardless of their name, I would not like to see functions like
these in Phobos. It's already challenging enough to keep the
signature of the larger Phobos modules in one's head. Adding
functions like these just adds noise... expressions like
(!s.empty) are perfectly readable.
Graham
"isBlank" works like this:
* If it's a string - it's considered blank if it's empty or
only contains white space
* If you can call "empty" on it - return the result
* If it's a reference type and it's null - return true
* Otherwise return false
