[armedbear-devel] More on proposed change to jar:file semantics
evenson at panix.com
Sat Jan 9 22:01:44 UTC 2010
I've managed to go pretty far down the road to implementing "jar:"
references "correctly" into ABCL so some closing notes for the night:
Alan Ruttenberg noted in private communication that [the javadoc for
java.net.URLConnection] has a pretty decent "specification" of what I
am trying to do, with the caveat that I am only implementing the "jar:"
for URIs in the "file:" schema. This suggests that we should look to
making PATHNAME more generic in supporting schemas like "http:". This
would all presumably thunk down to the support in java.net.URL, and only
be practically used for the "file" and "http" schemas. We might have a
problem with pathnames in that their namestrings could never start with
"file:" or "http:", but maybe we would be willing to sacrifice strict CL
compatibility here for a more natural fit. After all, we currently have
that for files that are called "jar:file:baz.jar!/foo". My hunch is
that there will be always be corner-cases in the pathname back and forth
to namestring interface that will always exist which is inherent in the
ANSI CL specification in that in leaves the actual semantics of DEVICE,
HOST, etc. up to implementations.
The documentation for JarURLConnection indicates that a URI that
references the JAR itself must always end in "!/" like
This makes my previous insistence that (pathname-device
#p"jar:file:baz.jar!/foo") return "baz" instead of "jar:file:baz.jar" a
little less necessary, so I will revisit this decision, especially in
light of the need for recursive jar file references.
The recursive entries arrise if I am going to implement the TRUENAME
stuff correctly (which will make the current LOAD code a lot less
hairy). Consider a JAR archive called "baz.jar". It contains an ABCL
packed FASL known as "bar.abcl" (i.e. "bar.abcl" is itself a JAR
containing "bar._", "bar-1.cls", "bar-2.cls", etc.). To reference the
first FASL stored in "jar:file:bar.abcl!/bar-1.cls", I propose use the
Seems to logically check out in my head, but if others spot an error
please chime in.
And the current implementation fails with
anyways as this is the part that started failing with the recent
"A screaming comes across the sky. It has happened before, but there
is nothing to compare to it now."
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