* Working evaluator.

* Mutually recursive attribute sets.
* Print evaluator efficiency statistics.

src/fix-ng/fix-expr.cc

@@ -31,3 +31,96 @@ ATerm bottomupRewrite(TermFun & f, ATerm e)
 
     return e;
 }
+
+
+void queryAllAttrs(Expr e, Attrs & attrs)
+{
+    ATermList bnds;
+    if (!ATmatch(e, "Attrs([<list>])", &bnds))
+        throw badTerm("expected attribute set", e);
+
+    while (!ATisEmpty(bnds)) {
+        char * s;
+        Expr e;
+        if (!ATmatch(ATgetFirst(bnds), "Bind(<str>, <term>)", &s, &e))
+            abort(); /* can't happen */
+        attrs[s] = e;
+        bnds = ATgetNext(bnds);
+    }
+}
+
+
+Expr queryAttr(Expr e, const string & name)
+{
+    Attrs attrs;
+    queryAllAttrs(e, attrs);
+    Attrs::iterator i = attrs.find(name);
+    return i == attrs.end() ? 0 : i->second;
+}
+
+
+Expr makeAttrs(const Attrs & attrs)
+{
+    ATermList bnds = ATempty;
+    for (Attrs::const_iterator i = attrs.begin(); i != attrs.end(); i++)
+        bnds = ATinsert(bnds, 
+            ATmake("Bind(<str>, <term>)", i->first.c_str(), i->second));
+    return ATmake("Attrs(<term>)", ATreverse(bnds));
+}
+
+
+ATerm substitute(Subs & subs, ATerm e)
+{
+    char * s;
+
+    if (ATmatch(e, "Var(<str>)", &s)) {
+        Subs::iterator i = subs.find(s);
+        if (i == subs.end())
+            return e;
+        else
+            return i->second;
+    }
+
+    /* In case of a function, filter out all variables bound by this
+       function. */
+    ATermList formals;
+    ATerm body;
+    if (ATmatch(e, "Function([<list>], <term>)", &formals, &body)) {
+        Subs subs2(subs);
+        ATermList fs = formals;
+        while (!ATisEmpty(fs)) {
+            if (!ATmatch(ATgetFirst(fs), "<str>", &s)) abort();
+            subs2.erase(s);
+            fs = ATgetNext(fs);
+        }
+        return ATmake("Function(<term>, <term>)", formals,
+            substitute(subs2, body));
+    }
+
+    /* !!! Rec(...) */
+
+    if (ATgetType(e) == AT_APPL) {
+        AFun fun = ATgetAFun(e);
+        int arity = ATgetArity(fun);
+        ATermList args = ATempty;
+
+        for (int i = arity - 1; i >= 0; i--)
+            args = ATinsert(args, substitute(subs, ATgetArgument(e, i)));
+        
+        return (ATerm) ATmakeApplList(fun, args);
+    }
+
+    if (ATgetType(e) == AT_LIST) {
+        ATermList in = (ATermList) e;
+        ATermList out = ATempty;
+
+        while (!ATisEmpty(in)) {
+            out = ATinsert(out, substitute(subs, ATgetFirst(in)));
+            in = ATgetNext(in);
+        }
+
+        return (ATerm) ATreverse(out);
+    }
+
+    return e;
+}