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Java/clang/flowing/Primitive.java

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+/*   
+Primitive.java
+ *    
+ *    Copyright (c) 2000, Ted Nelson and Tuomas Lukka
+ *
+ *    You may use and distribute under the terms of either the GNU Lesser
+ *    General Public License, either version 2 of the license or,
+ *    at your choice, any later version. Alternatively, you may use and
+ *    distribute under the terms of the XPL.
+ *
+ *    See the LICENSE.lgpl and LICENSE.xpl files for the specific terms of 
+ *    the licenses.
+ *
+ *    This software is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the README
+ *    file for more details.
+ *
+ */
+/*
+ * Written by Benjamin Fallenstein
+ */
+package org.gzigzag.flowing;
+import org.gzigzag.*;
+
+/** An Flowing Clang primitive.
+ */
+
+public abstract class Primitive {
+String rcsid = "$Id: Primitive.java,v 1.3 2000/10/13 13:52:24 bfallenstein Exp $";
+
+    // In subclasses, override one of the following two:
+    protected Data execute(Data params) { return null; }
+    public Data execute(Data params, ZZSpace space) {
+	return execute(params);
+    }
+
+    static public void count(Data pars, int n) { 
+	if(n != pars.len()) miscount();
+    }
+    static public void miscount() { throw new ZZError("Wrong parameter count"); }
+
+    /** Read a direction or step count from a parameter array.
+     * If the pos is out of the bounds of the array, +1 is assumed, so that
+     * the dir can optionally be left out.
+     * <p>
+     * (This, obviously, is just a convenience function.)
+     */
+    static int readsteps(Data pars, int pos) {
+	if(pos < pars.len()) {
+	    String stepstr = pars.s(pos);
+	    if(stepstr.equals("+"))
+		return 1;
+	    else if(stepstr.equals("-"))
+		return -1;
+	    else
+		return pars.i(pos);
+	} else {
+	    return 1;
+	}
+    }
+}
+
+