The previous definition of define-simple-macro would fail (with
a very poor error message) if the user made a simple macro like:
(define-simple-macro (~or a b)
(let ([tmp a])
(if tmp tmp b)))
While the define-simple-macro form does allow syntax-parse patterns,
this should not be enabled for the initial head pattern, as described
in the define-simple-macro documentation.
The dance that syntax/parse performs to lazily load its implementation
rewrites uses of syntax/parse macros in such a way that their original
names were discarded, which shows up in error messages. By simply
invoking the underlying transformer directly in the proxy macro instead
of expanding to a rewritten use, users’ names can be preserved.
fixes#1909
Note: quasisyntax has a bug: #`(... (1 2 #,@(list 3) 4)).
Within an escape, no way to express splicing desugaring.
So add a private variant of ?@ that is interpreted even escaped.
Make datum->syntax explicit in guide rather than combined with
constructors like t-cons/x and t-dots (conditional).
This will make datum support easier, later.
For now, it makes it easier to do relocate correctly.
Also, make t-metafun, h-splice inlinable.
* byte-regexp? values should not be considered 3D syntax.
* hash? values are now allowed in serialized syntax properties with (template … #:properties (…))
* marshalling properties which were prefab structs called map on the result of struct->vector, changed it to struct->list as the struct "name" is always serializable.
This change permits EH patterns like (~once <nullable>), because the
match will happen at most once, so there is no danger of divergence.
Thanks to Alex Knauth for pointing out this special case.
Merge to release branch.
In (~and p1 p2), a failure in p2 now always dominates a failure in p1.
Consequently, if a pattern succeeds, its failures don't matter.
Add {pat,hpat,action}:ord wrappers, ord prframes. Apply ordering to
main pattern and side clauses. Add better progress analysis to
eliminate order wrapping.
This is a partial solution to the ~and problem, only for side clauses.
In (~and p1 p2 p3), one often wants errors in p2 to take precedence over
errors in p1, and likewise for p3 over p2. One solution is ~commit, but
that prevents backtracking. Another is ~post, but then two ~post wrappers
are needed around p3. Also, it doesn't make sense to compare progress of
the third #:with clause from stxclass A to the second #:with clause of
stxclass B and say third beats second.
So, generalize 'post to (post group index); post frames are comparable to
each other only if group is the same, then compared by index. (Post still
beats CAR and CDR.) Each set of side clauses shares a group.
For simplicity of code generation for now, use gensyms to identify groups.
The symbol is used as the "who" field in the error message.
Also fix lazy-require of runtime-report.rkt in residual.rkt; don't
load until syntax-parse actually needs to produce an error report.
(Previously was loaded to create handler whenever syntax-parse code ran.)
