unstable/syntax: renamed syntax-local-values/{catch -> record}, changed uses

also added comments to some unstable/syntax functions

collects/redex/private/term.rkt

@@ -54,7 +54,7 @@
       [(metafunc-name arg ...)
        (and (identifier? (syntax metafunc-name))
             (term-fn? (syntax-local-value (syntax metafunc-name) (λ () #f))))
-       (rewrite-application (term-fn-get-id (syntax-local-value/catch (syntax metafunc-name) (λ (x) #t)))
+       (rewrite-application (term-fn-get-id (syntax-local-value/record (syntax metafunc-name) (λ (x) #t)))
                             (syntax/loc stx (arg ...))
                             depth)]
       [f
@@ -64,7 +64,7 @@
       [x
        (and (identifier? (syntax x))
             (term-id? (syntax-local-value (syntax x) (λ () #f))))
-       (let ([id (syntax-local-value/catch (syntax x) (λ (x) #t))])
+       (let ([id (syntax-local-value/record (syntax x) (λ (x) #t))])
          (values (datum->syntax (term-id-id id) (syntax-e (term-id-id id)) (syntax x))
                  (term-id-depth id)))]
       [(unquote x)

collects/syntax/private/stxparse/rep-data.rkt

@@ -260,7 +260,7 @@ DeclEntry =
   (define config (stxclass-lookup-config))
   (if (eq? config 'no)
       (make-dummy-stxclass id)
-      (cond [(syntax-local-value/catch id stxclass?) => values]
+      (cond [(syntax-local-value/record id stxclass?) => values]
             [(eq? config 'try)
              (make-dummy-stxclass id)]
             [else (wrong-syntax id "not defined as syntax class")])))

collects/syntax/private/stxparse/rep.rkt

@@ -1054,7 +1054,7 @@
 ;; check-literal-set-entry : stx stx -> (listof (list id id ct-phase^2))
 (define (check-literal-set-entry stx ctx)
   (define (elaborate litset-id lctx phase)
-    (let ([litset (syntax-local-value/catch litset-id literalset?)])
+    (let ([litset (syntax-local-value/record litset-id literalset?)])
       (unless litset
         (raise-syntax-error #f "expected identifier defined as a literal-set"
                             ctx litset-id))
@@ -1093,7 +1093,7 @@
 ;; returns (cons Conventions (listof syntax))
 (define (check-conventions stx ctx)
   (define (elaborate conventions-id args)
-    (let ([cs (syntax-local-value/catch conventions-id conventions?)])
+    (let ([cs (syntax-local-value/record conventions-id conventions?)])
       (unless cs
         (raise-syntax-error #f "expected identifier defined as a conventions"
                             ctx conventions-id))

collects/unstable/scribblings/syntax.scrbl

@@ -146,7 +146,7 @@ Generates a list of @racket[n] fresh identifiers.
 
 @;{----}
 
-@defparam[current-caught-disappeared-uses ids
+@defparam[current-recorded-disappeared-uses ids
           (or/c (listof identifier?) false/c)]{
 
 Parameter for tracking disappeared uses. Tracking is ``enabled'' when
@@ -165,33 +165,22 @@ object.
 
 }
 
-@defform[(with-catching-disappeared-uses body-expr)]{
-
-Evaluates the @racket[body-expr], catching identifiers looked up using
-@racket[syntax-local-value/catch]. Returns two values: the result of
-@racket[body-expr] and the list of caught identifiers.
-
-}
-
-@defproc[(syntax-local-value/catch [id identifier?] [predicate (-> any/c boolean?)])
+@defproc[(syntax-local-value/record [id identifier?] [predicate (-> any/c boolean?)])
          any/c]{
 
 Looks up @racket[id] in the syntactic environment (as
 @racket[syntax-local-value]). If the lookup succeeds and returns a
 value satisfying the predicate, the value is returned and @racket[id]
-is recorded (``caught'') as a disappeared use. If the lookup fails or
-if the value does not satisfy the predicate, @racket[#f] is returned
-and the identifier is not recorded as a disappeared use.
-
-If not used within the extent of a @racket[with-disappeared-uses] form
-or similar, has no effect.
+is recorded as a disappeared use. If the lookup fails or if the value
+does not satisfy the predicate, @racket[#f] is returned and the
+identifier is not recorded as a disappeared use.
 
 }
 
 @defproc[(record-disappeared-uses [ids (listof identifier?)])
          void?]{
 
-Add @racket[ids] to the current disappeared uses.
+Add @racket[ids] to @racket[(current-recorded-disappeared-uses)].
 
 If not used within the extent of a @racket[with-disappeared-uses] form
 or similar, has no effect.
@@ -408,7 +397,12 @@ object referring to one identifier into a syntax object referring to another.
 
 }
 
-@defproc[(head-expand [stx syntax?] [stop-list (listof identifier?)]) syntax?]{
+@defproc[(head-expand [stx syntax?]
+                      [stop-list (listof identifier?) null]
+                      [intdef-ctx (or/c internal-definitions-context?
+                                        (non-empty-listof internal-definitions-context?)
+                                        #f)])
+         syntax?]{
 
 This function performs head expansion on @scheme[stx].  In other words, it uses
 @scheme[local-expand] to expand @scheme[stx] until its head identifier is a core
@@ -416,7 +410,7 @@ form (a member of @scheme[(kernel-form-identifier-list)]) or a member of
 @scheme[stop-list], or until it can not be expanded further (e.g. due to error).
 
 It is equivalent to @scheme[(local-expand stx (syntax-local-context) (append
-stop-ids (kernel-form-identifier-list) #f))].
+stop-ids (kernel-form-identifier-list) intdef-ctx))].
 
 }
 

collects/unstable/syntax.rkt

@@ -17,10 +17,9 @@
          generate-temporary
          generate-n-temporaries
 
-         current-caught-disappeared-uses
-         with-catching-disappeared-uses
+         current-recorded-disappeared-uses
          with-disappeared-uses
-         syntax-local-value/catch
+         syntax-local-value/record
          record-disappeared-uses
 
          format-symbol
@@ -54,8 +53,8 @@
 
 ;; Unwrapping syntax
 
-;; unwrap-syntax : any #:stop-at (any -> boolean) -> any
-(define (unwrap-syntax stx #:stop-at [stop-at (lambda (x) #f)])
+;; unwrap-syntax : any #:stop (any -> boolean) -> any
+(define (unwrap-syntax stx #:stop [stop-at (lambda (x) #f)])
   (let loop ([x stx])
     (cond [(stop-at x) x]
           [(syntax? x) (loop (syntax-e x))]
@@ -70,6 +69,7 @@
 ;; Eli: Is there any difference between this (with the default) and
 ;;   `syntax->datum'?  If not, then maybe add the optional (or keyword) to
 ;;   there instead?
+;; Ryan: syntax->datum errors if its arg is not syntax.
 
 ;; Defining pattern variables
 
@@ -79,31 +79,28 @@
 
 ;; Statics and disappeared uses
 
-(define current-caught-disappeared-uses (make-parameter #f))
-
-(define-syntax-rule (with-catching-disappeared-uses . body)
-  (parameterize ((current-caught-disappeared-uses null))
-    (let ([result (let () . body)])
-      (values result (current-caught-disappeared-uses)))))
+(define current-recorded-disappeared-uses (make-parameter #f))
 
 (define-syntax-rule (with-disappeared-uses stx-expr)
   (let-values ([(stx disappeared-uses)
-                (with-catching-disappeared-uses stx-expr)])
+                (parameterize ((current-recorded-disappeared-uses null))
+                  (let ([result stx-expr])
+                    (values result (current-recorded-disappeared-uses))))])
     (syntax-property stx
                      'disappeared-use
                      (append (or (syntax-property stx 'disappeared-use) null)
                              disappeared-uses))))
 
-(define (syntax-local-value/catch id pred)
+(define (syntax-local-value/record id pred)
   (let ([value (syntax-local-value id (lambda () #f))])
     (and (pred value)
          (begin (record-disappeared-uses (list id))
                 value))))
 
 (define (record-disappeared-uses ids)
-  (let ([uses (current-caught-disappeared-uses)])
+  (let ([uses (current-recorded-disappeared-uses)])
     (when uses
-      (current-caught-disappeared-uses (append ids uses)))))
+      (current-recorded-disappeared-uses (append ids uses)))))
 
 ;; Generating temporaries
 
@@ -152,23 +149,6 @@
 ;;   single syntax among its inputs, and will use it for the context etc, or
 ;;   throw an error if there's more or less than 1.
 
-#|
-(define (id-append #:source [src #f]
-                   #:props [props #f]
-                   #:cert [cert #f]
-                   . args)
-  (define stxs (filter syntax? args))
-  (define lctx
-    (cond [(and (pair? stxs) (null? (cdr stxs)))
-           (car stxs)]
-          [(error 'id-append "expected exactly one identifier in arguments: ~e" args)]))
-  (define (convert x) (->atom x 'id-append))
-  (define sym (string->symbol (apply string-append (map convert args))))
-  (datum->syntax lctx sym src props cert))
-;; Eli: Yes, that looks nice (with the same comments as above on the keyword
-;;   args).  It makes more sense with the restriction on the format string.
-|#
-
 (define (restricted-format-string? fmt)
   (regexp-match? #rx"^(?:[^~]|~[aAn~%])*$" fmt))
 
@@ -205,6 +185,7 @@
                         extras)))
 ;; Eli: The `report-error-as' thing seems arbitrary to me.
 
+;; Applies the renaming of intdefs to stx.
 (define (internal-definition-context-apply intdefs stx)
   (let ([qastx (local-expand #`(quote #,stx) 'expression (list #'quote) intdefs)])
     (with-syntax ([(q astx) qastx]) #'astx)))
@@ -244,6 +225,7 @@
                   (define-syntax pvar
                     (make-syntax-mapping 'depth (quote-syntax valvar)))
                   ...)))]))
+;; Ryan: alternative name: define/syntax-pattern ??
 
 ;; auxiliary macro
 (define-syntax (pvar-value stx)
@@ -342,11 +324,12 @@
      "expected an identifier (alone or in application position); cannot redirect to ~a"
      (syntax-e id))]))
 
-(define (head-expand stx [stop-ids null])
+(define (head-expand stx [stop-ids null] [intdef-ctx #f])
   (local-expand stx
                 (syntax-local-context)
                 (append stop-ids (kernel-form-identifier-list))
-                #f))
+                intdef-ctx))
+;; Ryan: added intdef-ctx optional arg
 
 (define (quote-transformer datum)
   #`(quasiquote