suzanne.soy/racket
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Avoid tech collision.

Browse Source 
Closes #1484.
This commit is contained in:
Vincent St-Amour 2016-10-09 10:54:53 -05:00
parent e340719e5e
commit 241d87c011
1 changed files with 16 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
pkgs/racket-doc/scribblings/reference/stx-props.scrbl
View File

@ -5,10 +5,11 @@
Every syntax object has an associated @deftech{syntax property} list, Every syntax object has an associated @deftech{syntax property} list,
which can be queried or extended with which can be queried or extended with
@racket[syntax-property]. A property is set as @tech{preserved} or not; @racket[syntax-property]. A property is set as
a preserved property is maintained for a syntax object in a compiled form that is @deftech[#:key "stx-prop-preserved"]{preserved} or not; a preserved property is
marshaled to a byte string or @filepath{.zo} file, and other properties maintained for a syntax object in a compiled form that is marshaled to a byte
are discarded when marshaling. string or @filepath{.zo} file, and other properties are discarded when
marshaling.
In @racket[read-syntax], the reader attaches a preserved @racket['paren-shape] In @racket[read-syntax], the reader attaches a preserved @racket['paren-shape]
property to any pair or vector syntax object generated from parsing a property to any pair or vector syntax object generated from parsing a
@ -24,7 +25,8 @@ are merged by the syntax expander: each property in the original and
not present in the result is copied to the result, and the values of not present in the result is copied to the result, and the values of
properties present in both are combined with @racket[cons] (result properties present in both are combined with @racket[cons] (result
value first, original value second) and the @racket[cons]ed value is value first, original value second) and the @racket[cons]ed value is
@tech{preserved} if either of the values were preserved. @tech[#:key "stx-prop-preserved"]{preserved} if either of the values were
preserved.
Before performing the merge, however, the syntax expander Before performing the merge, however, the syntax expander
automatically adds a property to the original syntax object using the automatically adds a property to the original syntax object using the
@ -39,7 +41,8 @@ list of identifiers. However, a transformer might return
syntax that has already been expanded, in which case an syntax that has already been expanded, in which case an
@racket['origin] list can contain other lists after a merge. The @racket['origin] list can contain other lists after a merge. The
@racket[syntax-track-origin] procedure implements this tracking. @racket[syntax-track-origin] procedure implements this tracking.
The @racket['origin] property is added as non-@tech{preserved}. The @racket['origin] property is added as
non-@tech[#:key "stx-prop-preserved"]{preserved}.
Besides @racket['origin] tracking for general macro expansion, Besides @racket['origin] tracking for general macro expansion,
Racket adds properties to expanded syntax (often using Racket adds properties to expanded syntax (often using
@ -116,10 +119,10 @@ information on properties and byte codes.
The three- or four-argument form extends @racket[stx] by associating The three- or four-argument form extends @racket[stx] by associating
an arbitrary property value @racket[v] with the key @racket[key]; the an arbitrary property value @racket[v] with the key @racket[key]; the
result is a new syntax object with the association (while @racket[stx] result is a new syntax object with the association (while @racket[stx]
itself is unchanged). The property is added as @tech{preserved} if itself is unchanged). The property is added as
@racket[preserved?] is true, in which case @racket[key] must be an @tech[#:key "stx-prop-preserved"]{preserved} if @racket[preserved?] is true, in
@tech{interned} symbol, and @racket[v] should be a value as described which case @racket[key] must be an @tech{interned} symbol, and @racket[v]
below that can be saved in marshaled bytecode. should be a value as described below that can be saved in marshaled bytecode.
The two-argument form returns an arbitrary property value associated The two-argument form returns an arbitrary property value associated
to @racket[stx] with the key @racket[key], or @racket[#f] if no value to @racket[stx] with the key @racket[key], or @racket[#f] if no value
@ -157,8 +160,9 @@ attempt to marshal the owning syntax object to bytecode form.
@defproc[(syntax-property-preserved? [stx syntax?] [key (and/c symbol? symbol-interned?)]) @defproc[(syntax-property-preserved? [stx syntax?] [key (and/c symbol? symbol-interned?)])
boolean?]{ boolean?]{
Returns @racket[#t] if @racket[stx] has a @tech{preserved} property Returns @racket[#t] if @racket[stx] has a
value for @racket[key], @racket[#f] otherwise. @tech[#:key "stx-prop-preserved"]{preserved} property value for @racket[key],
@racket[#f] otherwise.
@history[#:added "6.4.0.14"]} @history[#:added "6.4.0.14"]}