Use new macro DRAIN-RESULT-LIST to simplify redundant code

s-expressionists · Jul 27, 2024 · 67c5018 · 67c5018
1 parent fe61a7c
commit 67c5018
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Showing 3 changed files with 13 additions and 13 deletions.
diff --git a/code/analyzer.lisp b/code/analyzer.lisp
@@ -56,10 +56,7 @@
   (let ((cache (cache analyzer)))
     (macrolet ((skip (reader popper)
                  `(progn
-                    (loop for maybe-wad = (,reader cache)
-                          while (and (not (null maybe-wad))
-                                     (position< (first maybe-wad) analyzer))
-                          do (,popper cache))
+                    (drain-result-list analyzer cache ,reader ,popper)
                     (,reader cache))))
       (let ((residue (skip residue pop-from-residue)))
         (cond ((null residue)

diff --git a/code/cache.lisp b/code/cache.lisp
@@ -201,6 +201,15 @@
 (defun push-to-residue (cache wad)
   (push wad (residue cache)))
 
+(defmacro drain-result-list (analyzer cache reader popper)
+  `(loop :for remaining = (,reader ,cache)
+         :while (and (not (null remaining))
+                     (position< (first remaining) ,analyzer))
+         ;; Detach before popping because detaching may traverse the
+         ;; ancestors of the wad and popping may sever the parent
+         ;; link.
+         :do (,popper ,cache)))
+
 (defun finish-scavenge (cache)
   ;; Move entire worklist to residue
   (loop until (null (worklist cache))

diff --git a/code/read.lisp b/code/read.lisp
@@ -127,12 +127,6 @@
           ;; the cache residue and cache suffix that are now before
           ;; the current stream position.
           unless (eq kind :whitespace)
-            do (macrolet ((clear (reader popper)
-                            `(loop :for remaining = (,reader cache)
-                                   :while (and (not (null remaining))
-                                               (position< (first remaining)
-                                                          analyzer))
-                                   :do (,popper cache))))
-                 (clear residue pop-from-residue)
-                 (when (null (residue cache))
-                   (clear suffix pop-from-suffix))))))
+            do (drain-result-list analyzer cache residue pop-from-residue)
+               (when (null (residue cache))
+                 (drain-result-list analyzer cache suffix pop-from-suffix)))))