diff options
| -rw-r--r-- | guix/memoization.scm | 21 |
1 files changed, 10 insertions, 11 deletions
diff --git a/guix/memoization.scm b/guix/memoization.scm index d64f60fe9c..5cae283610 100644 --- a/guix/memoization.scm +++ b/guix/memoization.scm @@ -31,9 +31,6 @@ (define-syntax-rule (return/1 value) value) -(define %nothing ;nothingness - (list 'this 'is 'nothing)) - (define-syntax define-cache-procedure (syntax-rules () "Define a procedure NAME that implements a cache using HASH-REF and @@ -41,15 +38,17 @@ HASH-SET!. Use CALL to invoke the thunk and RETURN to return its value; CALL and RETURN are used to distinguish between multiple-value and single-value returns." ((_ name hash-ref hash-set! call return) - (define (name cache key thunk) - "Cache the result of THUNK under KEY in CACHE, or return the + (define name + (let ((%nothing '(this is nothing))) + (lambda (cache key thunk) + "Cache the result of THUNK under KEY in CACHE, or return the already-cached result." - (let ((results (hash-ref cache key %nothing))) - (if (eq? results %nothing) - (let ((results (call thunk))) - (hash-set! cache key results) - (return results)) - (return results))))) + (let ((results (hash-ref cache key %nothing))) + (if (eq? results %nothing) + (let ((results (call thunk))) + (hash-set! cache key results) + (return results)) + (return results))))))) ((_ name hash-ref hash-set!) (define-cache-procedure name hash-ref hash-set! call/mv return/mv)))) |