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document this-syntax and #:auto-nested-attributes

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fixes #1185, #1350
This commit is contained in:
Ryan Culpepper 2016-07-29 16:33:34 -04:00
parent c56efb22a6
commit b7bd836f0f
1 changed files with 34 additions and 0 deletions
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34
pkgs/racket-doc/syntax/scribblings/parse/stxclasses.scrbl
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@ -27,6 +27,7 @@ structures can share syntax class definitions.
#:grammar
([stxclass-option
(code:line #:attributes (attr-arity-decl ...))
(code:line #:auto-nested-attributes)
(code:line #:description description-expr)
(code:line #:opaque)
(code:line #:commit)
@ -71,6 +72,20 @@ depths are not included, nor are nested attributes from
@tech{annotated pattern variables}.
}
@specsubform[#:auto-nested-attributes]{
@bold{Deprecated.} This option cannot be combined with @racket[#:attributes].
Declares the attributes of the syntax class as the set of all
@tech{pattern variables} and nested attributes from @tech{annotated
pattern variables} occurring in every variant of the syntax
class. Only syntax classes defined strictly before the enclosing
syntax class are used to compute the nested attributes; pattern
variables annotated with not-yet-defined syntax classes contribute no
nested attributes for export. Note that with this option, reordering
syntax-class definitions may change the attributes they export.
}
@specsubform[(code:line #:description description-expr)
#:contracts ([description-expr (or/c string? #f)])]{
@ -424,4 +439,23 @@ Returns the value associated with the @tech{attribute} named
error is raised.
}
@defidform[this-syntax]{
When used as an expression within a syntax-class definition or
@racket[syntax-parse] expression, evaluates to the syntax object or
@tech[#:doc '(lib "scribblings/reference/reference.scrbl")]{syntax
pair} being matched.
@examples[#:eval the-eval
(define-syntax-class one (pattern _ #:attr s this-syntax))
(syntax-parse #'(1 2 3) [(1 o:one _) (attribute o.s)])
(syntax-parse #'(1 2 3) [(1 . o:one) (attribute o.s)])
(define-splicing-syntax-class two (pattern (~seq _ _) #:attr s this-syntax))
(syntax-parse #'(1 2 3) [(t:two 3) (attribute t.s)])
(syntax-parse #'(1 2 3) [(1 t:two) (attribute t.s)])
]}
Raises an error when used as an expression outside of a syntax-class
definition or @racket[syntax-parse] expression.
@(close-eval the-eval)