Rearrange the configure scripts so that it will be possible to build
RacketCS from a source distribution and have it installed in the right
place. Also, when building Racket3m just to bootstrap RacketCS, don't
install Racket3m.
Retains a strong link to a place-channel write end when there's at
least one waiting thread. This is symmetic to keeping a strong link to
the read end when the place-channel queue is non-empty. The change
repairs a problem building documentation with places in `racocs
setup`.
There no longer seems to be any path that uses the 0-arity option for
a read result from a custom input-port that is a function for a
"special" result. Probably, that path got lost when I added a `source`
optional argument to `read-char-or-special`. If so, that effect of the
change wasn't intentional, but let's just be happy that a
simplification is in place.
Refines 2ef8d60cc6 to avoid characterizing the failure as a `(-> any)`
contract on `hash-ref`, since `hash-ref` doesn't enforce that contract
in general. Go back to an `exn:fail:contract:arity` error, but keep
the specialization of the error message to clarify that it's from
`hash-ref`. Also, bring RacketCS into sync.
If I have understood the behavior of ```app``` correctly, the documentation needs to be clarified. Currently it implies that match expects a single result, and one could reasonably infer that the matcher will require that single result to satisfy all ```_pat```s given. The error message resulting from a reasonable-but-wrong pattern like ```(app string->number (? number?) x)``` is inscrutable, so a doc fix is important here.
I have also added an example that illustrates the use case that led me to submit this PR.
Although a `directory-exists?` check is useful for providing better
error messages, it's fundentally a race condition, since an external
process can always remove a directory between the check and a use of
the directory. Because of that limitation of `directory-exists?`, we
normally avoid making it part of a contract. This commit adjust
937aa3cdb1 to follow that convention while preserving the helpful
check and documentation improvements.
