From 959c8d2c8be5eaf64db0feebc2069f3e87d7bca6 Mon Sep 17 00:00:00 2001
From: ccremers <ccremers@4f7d145f-a0d4-0310-ae10-d96cc04433c1>
Date: Thu, 26 Aug 2004 12:36:01 +0000
Subject: [PATCH] - Added termlist_to_tuple function.

---
 src/termlist.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++
 src/termlist.h |  1 +
 2 files changed, 52 insertions(+)

diff --git a/src/termlist.c b/src/termlist.c
index ae4f4e9..7aa04d9 100644
--- a/src/termlist.c
+++ b/src/termlist.c
@@ -790,3 +790,54 @@ termlist_iterate (Termlist tl, int (*func) ())
     }
   return 1;
 }
+
+//! Create a tuple term from a termlist
+Term termlist_to_tuple (Termlist tl)
+{
+  int width;
+
+  width = termlistLength (tl);
+  if (width > 1)
+    {
+      // 2 parts
+      // Make two termlists for each side.
+      Term tresult;
+      Termlist tl1, tl2;
+      int split, i;
+
+      /**
+       * This can be done much more efficiently by cutting
+       * the list temporarily, and reconnecting it afterwards.
+       */
+      tl1 = NULL;
+      tl2 = NULL;
+      split = width / 2;
+      i = 0;
+      while (tl != NULL)
+	{
+	  if (i < split)
+	      tl1 = termlistAdd (tl1, tl->term);
+	  else
+	      tl2 = termlistAdd (tl2, tl->term);
+	  tl = tl->next;
+	  i++;
+	}
+      tresult = makeTermTuple (termlist_to_tuple (tl1), termlist_to_tuple (tl2));
+      termlistDelete (tl1);
+      termlistDelete (tl2);
+      return tresult;
+    }
+  else
+    {
+      if (tl == NULL)
+	{
+	  // W00t! Wtf?
+	  error ("termlist_to_tuple called (internally?) with NULL");
+	}
+      else
+	{
+	  // Single node, simple
+	  return termDuplicate(tl->term);
+	}
+    }
+}
diff --git a/src/termlist.h b/src/termlist.h
index a20e5c5..dc917a4 100644
--- a/src/termlist.h
+++ b/src/termlist.h
@@ -55,5 +55,6 @@ Term termFunction (Termlist fromlist, Termlist tolist, Term tx);
 Termlist termlistForward (Termlist tl);
 int termlistOrder (Termlist tl1, Termlist tl2);
 int termlist_iterate (Termlist tl, int (*func) ());
+Term termlist_to_tuple (Termlist tl);
 
 #endif