created mirror

Java/clang/thales/SyntaxForm.java

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+/*   
+SyntaxForm.java
+ *    
+ *    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 Antti-Juhani Kaijanaho.
+ */
+
+package org.gzigzag.clang.thales;
+
+import org.gzigzag.*;
+import java.lang.reflect.*;
+
+/** Syntax form.  Subclasses must have at least two constructors: one
+    taking a ZZCell as an argument (the cell must be used to deduce
+    existing runtime state) and another taking two ZZCells as
+    arguments (the first cell must be used for parsing the expression,
+    the other cell must be understood to mean the cell that should be
+    updated to point to the result of the expression).  */
+public abstract class SyntaxForm implements Refcounted {
+    
+    static protected ZZCell newRT(ZZSpace space, Class cl) {
+        String name = cl.getName();
+        name = name.substring(name.lastIndexOf(".")+1);
+        ZZCell home = space.getHomecell();
+        ZZCell namec = home.findText(DimensionNames.syntaxformlist, 1, name);
+        if (namec == null) {
+            namec = home.N(DimensionNames.syntaxformlist, 1);
+            namec.setText(name);
+        }
+        return namec.zzclone();
+    }
+
+    static public SyntaxForm rt_instantiate(ZZCell c, Evaluator etor) {
+        ZZCell sfc = c.h("d.clone");
+
+        if (sfc == null) throw new ZZError("no d.clone headcell");
+
+        if (sfc.h(DimensionNames.syntaxformlist) != sfc.getHomecell()) {
+            throw new ZZError("not in syntax form list");
+        }
+        
+        Object o;
+
+        try {
+            Class cl = Class.forName("org.gzigzag.clang.thales.syntaxform"
+                                     + name);
+            Class cellcl = Class.forName("org.gzigzag.ZZCell");
+            Constructor ctor = cl.getConstructor(new Class[] { cellcl });
+            o = ctor.newInstance(new Object[] { c } );
+        } catch (ClassNotFoundException e) {
+            throw new ZZError("syntax form not found (" + e + ")");
+        } catch (InstantiationException e) {
+            throw new ZZError("problems instantiating syntax form: " + e);
+        } catch (IllegalAccessException e) {
+            throw new ZZError("" + e);
+        }
+        
+        if (!(o instanceof SyntaxForm)) throw new InvalidException();
+
+        SyntaxForm rv = (SyntaxForm) o;
+
+        rv.etor = etor;
+
+        return rv;
+    }
+
+    static public SyntaxForm code_instantiate(ZZCell code, ZZCell rv, 
+                                              Evaluator etor) {
+        ZZCell sfc = code.h(DimensionNames.syntaxform);
+
+        if (sfc == null) throw new ZZError("invalid syntax form");
+
+        Object o;
+
+        try {
+            Class cl = Class.forName("org.gzigzag.clang.thales.syntaxform"
+                                     + sfc);
+            Class cellcl = Class.forName("org.gzigzag.ZZCell");
+            Constructor ctor = cl.getConstructor(new Class[] { cellcl, cellcl });
+            o = ctor.newInstance(new Object[] { c, rv } );
+        } catch (ClassNotFoundException e) {
+            throw new ZZError("syntax form not found (" + e + ")");
+        } catch (InstantiationException e) {
+            throw new ZZError("problems instantiating syntax form: " + e);
+        } catch (IllegalAccessException e) {
+            throw new ZZError("" + e);
+        }
+        
+        if (!(o instanceof SyntaxForm)) throw new InvalidException();
+
+        SyntaxForm rv = (SyntaxForm)o;
+        rv.etor = etor;
+        return rv;
+    }
+
+    private ZZCell base;
+    private Evaluator etor = null;
+
+    /** Construct oneself using an existing syntax form runtime
+        cell. */
+    protected SyntaxForm(ZZCell c) {
+        base = c;
+    }
+
+    /** Construct oneself using a new syntax form runtime cell. */
+    protected SyntaxForm(ZZSpace s) {
+        this(SyntaxForm.newRT(s, this.getClass()));
+    }
+
+    protected SyntaxForm code_instantiate(ZZCell code, ZZCell rv) {
+        SyntaxForm.code_instantiate(code, rv, etor);
+    }
+
+    protected final ZZCell getBaseCell() { return base; }
+    protected final void requestEval(SyntaxForm sf) { etor.request(sf); }
+    protected final void finishEval() { etor.finishEval(this); }
+    protected final void setCurrentEnvironment(Environment e) {
+        etor.setCurrentEnvironment(e);
+    }
+    protected final Environment getCurrentEnvironment() {
+        return etor.getCurrentEnvironment();
+    }
+
+    public abstract void evalIteration();
+
+    /** Delete the runtime representation unconditionally.  */
+    protected abstract void delete();
+
+    private int getReferenceCount() {
+        String text = cell.getText();
+        if (text.equals("")) {
+            setReferenceCount(0);
+            return getReferenceCount();
+        }
+        return Integer.parseInt(text);
+    }
+
+    private void setReferenceCount(int rc) {
+        cell.setText("" + rc);
+    }
+
+    public final void registerReference() {
+        setReferenceCount(getReferenceCount() + 1);
+    }
+
+    public final void unregisterReference() {
+        setReferenceCount(getReferenceCount() - 1);
+        if (getReferenceCount() < 1) {
+            delete();
+            cell.delete();
+        }
+    }
+
+}