wl

commit 2e90a3297e09e10cc66d6ccf62c772d891aae409
parent 2ecf1c5b82c89185f2ac2970eac5b178090be322
Author: tomas <tomas@logand.com>
Date:   Sun, 18 Oct 2009 00:02:46 +0200

~ reader

Diffstat:
M
wl.java
 | 
9
+++++++--

1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/wl.java b/wl.java
@@ -189,6 +189,7 @@ class wl implements Runnable {
     // reader
     final static Any Lp = mkObj(null);
     final static Any Rp = mkObj(null);
+    final static Any Tld = mkObj(null);
 
     final Any Qte = mkIsym("quote", NIL);
     final Any Dot = mkIsym(".", NIL);
@@ -296,6 +297,7 @@ class wl implements Runnable {
             case '"': xchar(); Z = text(); break;
             case '\'': xchar(); Z = mkCons(Qte, read1(false)); break;
             case '`': xchar(); Z = eval(read1(false)); break;
+            case '~': if(Top) Z = symbol(); else {xchar(); Z = Tld;} break;
             default: Z = symbol();
             }
         }
@@ -306,12 +308,15 @@ class wl implements Runnable {
         Any Z = A;
         Any X;
         boolean D = false;
+        boolean E = false;
         while(null != (X = read1(false)) && Rp != X) {
-            if(Dot != X) {
+            if(Dot != X && Tld != X) {
+                if(E) {X = eval(X); E = false;}
                 Z.cdr(D ? X : mkCons(X, NIL));
                 if(Z.cdr().isCons()) Z = Z.cdr();
             }
-            D = Dot == X;
+            D = Dot == X || Tld == X;
+            E = Tld == X;
         }
         if(null == X) err("Reader underflow");
         if(D) Z.cdr(A.cdr());