(zilch nix path): support content-addressed paths with references

core/src/nix/path.sld

@@ -3,13 +3,14 @@
 ;; These helpers all use the `%store-dir` parameter as base store directory.
 (define-library (zilch nix path)
   (import
-    (scheme base)
+    (scheme base) (srfi 152)
     (zilch lib hash) (zilch nix hash))
 
   (export
     %store-dir
     impure-placeholder make-upstream-output-placeholder make-placeholder
-    make-store-path-from-parts make-text-path make-fixed-output-path make-output-path)
+    make-store-path-from-parts make-text-path make-fixed-output-path make-output-path
+    make-fixed-output-with-references)
 
   (begin
     ;; The path to the store dir, as a parameter.
@@ -61,4 +62,9 @@
           (sha256
             (string->utf8
                (string-append "fixed:out:" (if recursive "r:" "") hash-algo ":" (hex hash-value) ":")))
-          name)))))
+          name)))
+
+    (define (make-fixed-output-with-references hash-value name references self-references)
+      (make-store-path-from-parts
+        (string-join (append (cons "source" references) (if self-references '("self") '())) ":")
+        "sha256" hash-value name))))