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Prefix, not postfix

This page is part of the web mail archives of SRFI 88 from before July 7th, 2015. The new archives for SRFI 88 contain all messages, not just those from before July 7th, 2015.

The SRFI specifies a new kind of datatype, the keyword. Any symbol
can be turned into a keyword by adding a colon to the end.

I think this is a bad idea.

Everywhere else in Scheme, I can recognize the kind of an object
by looking at the start of the name, never by looking at the end.
Postfix is only used as a convention to signify a mutating
operator or predicates. But in that case, the kind of object
doesn't change due to the postfix syntax - it's still an operator.

I don't think that the argument put forth in the SRFI, according
to which a postfix colon is used because that does not conflict
with R5RS, is a good reason to decrease consistency and

The only remaining argument I can think of in favor of the postfix
colon is that it's more natural to write "foo: bar" - but the same
way Scheme prefers to use prefix math operators for consistence
instead of using the "more natural" infix syntax, I think using
":foo bar" is more consistent with the rest of Scheme.

The ":foo" syntax has precedence in many Scheme implementations,
as stated in the SRFI itself. If we want to standardize on a
keyword datatype and syntax, we should make it consistent with
Scheme, and not just "compatible with R5RS".

Semi-long posting, short summary: If we do indeed have to
standardize keywords, please use prefix colons. :-)

        -- Jorgen

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