transformations: Relax the rules for transformation finalizing.

The trns_chain data structure has a barely useful concept called
"finalization".  In practice this is used to make sure that control
structures (e.g. DO IF) that are opened get closed (e.g. END IF).  There
are currently some restrictions on finalizing: namely, transformations
can't be added after a chain is finalized.  Since finalizers are barely
used, we can relax this restriction, which this commit does.  This will be
used in an upcoming commit where the ability to add a transformation to a
finalized change becomes useful for a corner case.

diff --git a/src/data/transformations.c b/src/data/transformations.c
index 8321cf5d4eba5ef2e9674bb6cd9ada6977311141..7f8672805f1983879934dff1fe0bbaf3996a7381 100644 (file)
--- a/src/data/transformations.c
+++ b/src/data/transformations.c
@@ -1,5 +1,5 @@
 /* PSPP - a program for statistical analysis.
-   Copyright (C) 1997-9, 2000, 2006, 2009, 2011 Free Software Foundation, Inc.
+   Copyright (C) 1997-9, 2000, 2006, 2009, 2011, 2013 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -59,26 +59,25 @@ trns_chain_create (void)
   return chain;
 }
 
-/* Finalizes all the transformations in CHAIN.
-   A chain is only finalized once; afterward, calling this
-   function is a no-op.
-   Finalizers may add transformations to CHAIN, but after
-   finalization the chain's contents are fixed, so that no more
-   transformations may be added afterward. */
+/* Finalizes all the un-finalized transformations in CHAIN.
+   Any given transformation is only finalized once. */
 void
 trns_chain_finalize (struct trns_chain *chain)
 {
-  if (!chain->finalized)
+  while (!chain->finalized)
     {
       size_t i;
 
+      chain->finalized = true;
       for (i = 0; i < chain->trns_cnt; i++)
         {
           struct transformation *trns = &chain->trns[i];
-          if (trns->finalize != NULL)
-            trns->finalize (trns->aux);
+          trns_finalize_func *finalize = trns->finalize;
+
+          trns->finalize = NULL;
+          if (finalize != NULL)
+            finalize (trns->aux);
         }
-      chain->finalized = true;
     }
 }
 
@@ -127,7 +126,7 @@ trns_chain_append (struct trns_chain *chain, trns_finalize_func *finalize,
 {
   struct transformation *trns;
 
-  assert (!chain->finalized);
+  chain->finalized = false;
 
   if (chain->trns_cnt == chain->trns_cap)
     chain->trns = x2nrealloc (chain->trns, &chain->trns_cap,