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-rw-r--r--doc/api/utils.texi11
-rw-r--r--sly/utils.scm21
2 files changed, 30 insertions, 2 deletions
diff --git a/doc/api/utils.texi b/doc/api/utils.texi
index 308daee..4858010 100644
--- a/doc/api/utils.texi
+++ b/doc/api/utils.texi
@@ -72,7 +72,7 @@ an object within the guardian is GC'd. Reaping is ensured to happen
from the same thread that is running the game loop.
@end deffn
-@deffn memoize @var{proc}
+@deffn {Scheme Procedure} memoize @var{proc}
Return a memoizing version of @code{proc}.
@end deffn
@@ -108,3 +108,12 @@ Like @code{chain*} but for a single argument.
@end example
@end deffn
+
+@deffn {Scheme Procedure} list->vlist* @var{lst}
+Convert @code{lst} and all sub-lists within to vlists.
+@end deffn
+
+@deffn {Scheme Procedure} list->vlist* @var{lst} @var{index} [@dots{}]
+Return the element at index @code{index @dots{}} in the nested vlist
+structure @code{vlist}.
+@end deffn
diff --git a/sly/utils.scm b/sly/utils.scm
index 7256ab6..0e38fe4 100644
--- a/sly/utils.scm
+++ b/sly/utils.scm
@@ -23,6 +23,8 @@
;;; Code:
(define-module (sly utils)
+ #:use-module (ice-9 match)
+ #:use-module (ice-9 vlist)
#:use-module (srfi srfi-1)
#:use-module (rnrs arithmetic bitwise)
#:use-module (sly agenda)
@@ -30,7 +32,8 @@
memoize
forever
trampoline
- chain* chain))
+ chain* chain
+ list->vlist* vlist-ref*))
(define-syntax-rule (define-guardian name reaper)
"Define a new guardian called NAME and call REAPER when an object
@@ -78,3 +81,19 @@ same thread that is running the game loop."
(define-syntax-rule (chain arg (proc ...) . rest)
(chain* (list arg) (proc ...) . rest))
+
+(define (list->vlist* lst)
+ "Convert LST and all sub-lists within to vlists."
+ (list->vlist
+ (map (match-lambda
+ ((sub-lst ...)
+ (list->vlist* sub-lst))
+ (obj obj))
+ lst)))
+
+(define (vlist-ref* vlist index . rest)
+ "Return the element at index INDEX ... in the nested vlist structure
+VLIST."
+ (if (null? rest)
+ (vlist-ref vlist index)
+ (apply vlist-ref* (vlist-ref vlist index) rest)))