The `#%module-begin' of `racket/base' and `scheme/base' now introduces
a suitable `configure-runtime' submodule, instead of using the
`module->language-info' path.
A submodule is a lot easier to work with, as illustrated by the
removal of the `racket/private/lang' and `scheme/private/lang'
languages.
Also, add `#%printing-module-begin', which is the old `#%module-begin'
(i.e., the one that doesn't introduce a `configure-runtime' submodule).
Support for break clauses complicates expansion to `for/fold/derived';
a new `syntax/for-body' library provides a helper for macros that need
to split a `for'-style body into a prefix part and wrappable part.
The new parameter (and supporting environment variables and
command-line flags) can bytecode lookup to a tree other than
where a source file resides, so that sources and generated
compiled files can be kept separate. It also supports storing
bytecode files in a version-specific location (either with
the source or elsewhere).
Paths are left as paths, instead of trying to convert them to strings
or byte strings. Submodule path elements should be unquoted -- in the
same form as a `submod' form. All extra parts are submodule path elements,
never module paths or ".".
Caveats:
- keyword function definitions do not define static
bindings, thus limiting optimization opportunities
- can't use `define:`, `lambda:`, etc with keywords
- error messages sometimes expose the implementation
- the optimizer skips most of the generated code for
keyword functions definitions (user-level code is
optimized)
The preserved path is exposed by a new `module-path-index-submodule'
function, and `module-path-index-join' now accepts an optional
submodule path.
Also, fixed a problem with `collapse-module-path-index' when
a module path indx is built on a resolved module path that
is a submodule path.
In addition to the main repair, `collapse-module-path[-index]' is
correctly documented to allow '(quote <sym>) rel-to paths.
Finally, `collapse-module-path-index' changed to use a symbolic
resolved module path that appears as the base of a module path
index, rather than falling back to the given rel-to path. It's
possble that the old beavior was intentional, but it wasn't tested,
and it seems more likely to have been a bug.
Closes PR 12724
This library is used by Redex, which wants a `syntax'-like template
language, but for datum values instead of syntax objects. Using
`datum-case' and `datum' generates much less code. Redex uses
only a small part of the general functionality, so adding
`syntax/datum' could be overkill. It's implemented by generalizing
the `syntax-case' and `syntax' pattern matching and template
constructing code, though; it's not a lot of extra code, and it's
easiest to generalize completely. We may find other uses for
datum templates, too.
