[R6RS] inconsistent naming of arithmetic predicates
Anton van Straaten
anton at appsolutions.com
Thu Jun 29 15:54:57 EDT 2006
> I would like to rename the SRFI 77 predicates
> by adopting one of these two rules:
> 1. No question mark is added for predicates
> corresponding to =, <, or >.
Is that intended to include >= and <= ? If not, I think it should.
> 2. If the predicate contains any letters at
> all, then it ends with a question mark.
> These two rules would give us these options:
> 1. =
> 2. =
> I prefer the first. The second would be more
> consistent with the rule that gave us char=?,
> string=?, char-ci=?, and string-ci=?.
I vote for rule 1. My order of preference is 1, 1, 1. I have four
reasons for this:
1. The predicate seems implicit in =, <. >, <=. and >=. The question
mark isn't necessary.
2. The convention in rule 1 is already used by the generic arithmetic
comparison operator names. A question mark would be inconsistent with
that convention, at least for predicates which apply to numeric types.
3. For identifiers which already end in punctuation, adding a question
mark adds noise, visually, without adding information.
4. For identifiers which already end in punctuation, the question mark
makes them slightly more difficult to type (on a QWERTY keyboard, at least).
As a counterpoint to point 2 above, the rule 1 convention is
inconsistent with the string and char predicates, and a few others.
However, that inconsistency already exists with the generic arithmetic
We could eliminate the inconsistency entirely by removing the question
mark from all such predicates: 20 R5RS string and char predicates, plus
the three new predicates free-identifier=?, bound-identifier=?, and
bytes=?. The old R5RS names could be moved into the compatibility library.
Otherwise, the choice is between being consistent across names which
apply to numeric values, or being consistent across names which contain
alphabetic characters. Consistency based on the semantics of the
operation seems more important than consistency based on a superficial
property of their names.
Finally, there's a possible benefit in having a strict rule that all
predicate names end in a question mark. It makes them slightly easier
to type in the "x x -> boolean" sense. But all Rule 1 does is add to
the number of suffixes which can signify a predicate. This a minor issue.
OK, I painted the shed. Did I miss any spots?
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