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-rw-r--r--libguile/ports.c5
-rw-r--r--module/ice-9/boot-9.scm33
-rw-r--r--module/srfi/srfi-39.scm101
-rw-r--r--test-suite/tests/parameters.test61
4 files changed, 106 insertions, 94 deletions
diff --git a/libguile/ports.c b/libguile/ports.c
index 677b2789a..a6311003a 100644
--- a/libguile/ports.c
+++ b/libguile/ports.c
@@ -2582,6 +2582,11 @@ scm_init_ports ()
(scm_from_int ((int) SCM_FAILED_CONVERSION_QUESTION_MARK)));
scm_conversion_strategy_init = 1;
+ /* These bindings are used when boot-9 turns `current-input-port' et
+ al into parameters. They are then removed from the guile module. */
+ scm_c_define ("%current-input-port-fluid", cur_inport_fluid);
+ scm_c_define ("%current-output-port-fluid", cur_outport_fluid);
+ scm_c_define ("%current-error-port-fluid", cur_errport_fluid);
}
/*
diff --git a/module/ice-9/boot-9.scm b/module/ice-9/boot-9.scm
index d5ba67a6d..03dad9b0d 100644
--- a/module/ice-9/boot-9.scm
+++ b/module/ice-9/boot-9.scm
@@ -2915,6 +2915,36 @@ module '(ice-9 q) '(make-q q-length))}."
;;;
+;;; Current ports as parameters.
+;;;
+
+(let ((fluid->parameter
+ (lambda (fluid conv)
+ (make-struct <parameter> 0
+ (case-lambda
+ (() (fluid-ref fluid))
+ ((x) (let ((prev (fluid-ref fluid)))
+ (fluid-set! fluid (conv x))
+ prev)))
+ fluid conv))))
+ (define-syntax-rule (port-parameterize! binding fluid predicate msg)
+ (begin
+ (set! binding (fluid->parameter (module-ref (current-module) 'fluid)
+ (lambda (x)
+ (if (predicate x) x
+ (error msg x)))))
+ (module-remove! (current-module) 'fluid)))
+
+ (port-parameterize! current-input-port %current-input-port-fluid
+ input-port? "expected an input port")
+ (port-parameterize! current-output-port %current-output-port-fluid
+ output-port? "expected an output port")
+ (port-parameterize! current-error-port %current-error-port-fluid
+ output-port? "expected an output port"))
+
+
+
+;;;
;;; Warnings.
;;;
@@ -3657,8 +3687,9 @@ module '(ice-9 q) '(make-q q-length))}."
srfi-4 ;; homogenous numeric vectors
srfi-6 ;; open-input-string etc, in the guile core
srfi-13 ;; string library
- srfi-23 ;; `error` procedure
srfi-14 ;; character sets
+ srfi-23 ;; `error` procedure
+ srfi-39 ;; parameterize
srfi-55 ;; require-extension
srfi-61 ;; general cond clause
))
diff --git a/module/srfi/srfi-39.scm b/module/srfi/srfi-39.scm
index d1c46d028..0d540633d 100644
--- a/module/srfi/srfi-39.scm
+++ b/module/srfi/srfi-39.scm
@@ -35,104 +35,19 @@
;;; Code:
(define-module (srfi srfi-39)
- #:use-module (srfi srfi-16)
-
- #:export (make-parameter)
- #:export-syntax (parameterize)
-
;; helper procedure not in srfi-39.
#:export (with-parameters*)
- #:replace (current-input-port current-output-port current-error-port))
-
-;; Make 'srfi-39 available as a feature identifiere to `cond-expand'.
-;;
-(cond-expand-provide (current-module) '(srfi-39))
-
-(define make-parameter
- (case-lambda
- ((val) (make-parameter/helper val (lambda (x) x)))
- ((val conv) (make-parameter/helper val conv))))
-
-(define get-fluid-tag (lambda () 'get-fluid)) ;; arbitrary unique (as per eq?) value
-(define get-conv-tag (lambda () 'get-conv)) ;; arbitrary unique (as per eq?) value
-
-(define (make-parameter/helper val conv)
- (let ((fluid (make-fluid (conv val))))
- (case-lambda
- (()
- (fluid-ref fluid))
- ((new-value)
- (cond
- ((eq? new-value get-fluid-tag) fluid)
- ((eq? new-value get-conv-tag) conv)
- (else (fluid-set! fluid (conv new-value))))))))
-
-(define-syntax-rule (parameterize ((?param ?value) ...) ?body ...)
- (with-parameters* (list ?param ...)
- (list ?value ...)
- (lambda () ?body ...)))
+ #:re-export (make-parameter
+ parameterize
+ current-input-port current-output-port current-error-port))
-(define current-input-port
- (case-lambda
- (()
- ((@ (guile) current-input-port)))
- ((new-value)
- (set-current-input-port new-value))))
-
-(define current-output-port
- (case-lambda
- (()
- ((@ (guile) current-output-port)))
- ((new-value)
- (set-current-output-port new-value))))
-
-(define current-error-port
- (case-lambda
- (()
- ((@ (guile) current-error-port)))
- ((new-value)
- (set-current-error-port new-value))))
-
-(define port-list
- (list current-input-port current-output-port current-error-port))
-
-;; There are no fluids behind current-input-port etc, so those parameter
-;; objects are picked out of the list and handled separately with a
-;; dynamic-wind to swap their values to and from a location (the "value"
-;; variable in the swapper procedure "let").
-;;
-;; current-input-port etc are already per-dynamic-root, so this arrangement
-;; works the same as a fluid. Perhaps they could become fluids for ease of
-;; implementation here.
-;;
-;; Notice the use of a param local variable for the swapper procedure. It
-;; ensures any application changes to the PARAMS list won't affect the
-;; winding.
-;;
(define (with-parameters* params values thunk)
(let more ((params params)
(values values)
(fluids '()) ;; fluids from each of PARAMS
- (convs '()) ;; VALUES with conversion proc applied
- (swapper noop)) ;; wind/unwind procedure for ports handling
+ (convs '())) ;; VALUES with conversion proc applied
(if (null? params)
- (if (eq? noop swapper)
- (with-fluids* fluids convs thunk)
- (dynamic-wind
- swapper
- (lambda ()
- (with-fluids* fluids convs thunk))
- swapper))
- (if (memq (car params) port-list)
- (more (cdr params) (cdr values)
- fluids convs
- (let ((param (car params))
- (value (car values))
- (prev-swapper swapper))
- (lambda ()
- (set! value (param value))
- (prev-swapper))))
- (more (cdr params) (cdr values)
- (cons ((car params) get-fluid-tag) fluids)
- (cons (((car params) get-conv-tag) (car values)) convs)
- swapper)))))
+ (with-fluids* fluids convs thunk)
+ (more (cdr params) (cdr values)
+ (cons (parameter-fluid (car params)) fluids)
+ (cons ((parameter-converter (car params)) (car values)) convs)))))
diff --git a/test-suite/tests/parameters.test b/test-suite/tests/parameters.test
index 9d0a092ab..78b57c68d 100644
--- a/test-suite/tests/parameters.test
+++ b/test-suite/tests/parameters.test
@@ -67,3 +67,64 @@
(lambda ()
(parameterize ((inside? #t))
(raise 'some-exception)))))))))
+
+(let ()
+ (define (test-ports param new-port new-port-2)
+ (let ((old-port (param)))
+
+ (pass-if "new value"
+ (parameterize ((param new-port))
+ (eq? (param) new-port)))
+
+ (pass-if "set value"
+ (parameterize ((param old-port))
+ (param new-port)
+ (eq? (param) new-port)))
+
+ (pass-if "old restored"
+ (parameterize ((param new-port))
+ #f)
+ (eq? (param) old-port))
+
+ (pass-if "throw exit"
+ (catch 'bail
+ (lambda ()
+ (parameterize ((param new-port))
+ (throw 'bail)))
+ (lambda args #f))
+ (eq? (param) old-port))
+
+ (pass-if "call/cc re-enter"
+ (let ((cont #f)
+ (count 0)
+ (port #f)
+ (good #t))
+ (parameterize ((param new-port))
+ (call/cc (lambda (k) (set! cont k)))
+ (set! count (1+ count))
+ (set! port (param))
+ (if (= 1 count) (param new-port-2)))
+ (set! good (and good (eq? (param) old-port)))
+ (case count
+ ((1)
+ (set! good (and good (eq? port new-port)))
+ ;; re-entering should give new-port-2 left there last time
+ (cont))
+ ((2)
+ (set! good (and good (eq? port new-port-2)))))
+ good))
+
+ (pass-if "original unchanged"
+ (eq? (param) old-port))))
+
+ (with-test-prefix "current-input-port"
+ (test-ports current-input-port
+ (open-input-string "xyz") (open-input-string "xyz")))
+
+ (with-test-prefix "current-output-port"
+ (test-ports current-output-port
+ (open-output-string) (open-output-string)))
+
+ (with-test-prefix "current-error-port"
+ (test-ports current-error-port
+ (open-output-string) (open-output-string))))