adding extremely crude jython and clojure expression evaluation

git-svn-id: http://google-refine.googlecode.com/svn/trunk@276 7d457c2a-affb-35e4-300a-418c747d4874

src/main/java/com/metaweb/gridworks/expr/JythonEvaluable.java

@@ -0,0 +1,56 @@
+package com.metaweb.gridworks.expr;
+
+import java.util.Enumeration;
+import java.util.Properties;
+
+import org.python.core.PyException;
+import org.python.core.PyString;
+import org.python.util.PythonInterpreter;
+
+public class JythonEvaluable implements Evaluable {
+
+	private String _code;
+	private static final String _functionName = "temp";
+    private static PythonInterpreter _engine = new PythonInterpreter();
+
+
+    public JythonEvaluable(String s) {
+    	// indent and create a function out of the code
+    	String[] lines = s.split("\r\n|\r|\n");
+    	StringBuilder function = new StringBuilder();
+    	function.append("def " + _functionName + "():");
+    	for (int i = 0; i < lines.length; i++) {
+    		function.append("\n    " + lines[i]);    		
+    	}
+    	_code = function.toString();
+    }
+    
+	public Object evaluate(Properties bindings) {
+		try {
+			for (Enumeration<Object> e = bindings.keys() ; e.hasMoreElements() ;) {
+				Object k = e.nextElement();
+				Object v = bindings.get(k);
+				if (v instanceof HasFields) {
+					_engine.set((String)k, new JythonHasFieldsWrapper((HasFields) v, bindings));
+				} else {
+					_engine.set((String) k, v);
+				}
+			}
+			_engine.exec(_code);
+			
+			Object result = _engine.eval(_functionName + "()");
+
+			// unwrap the underlying Java objects
+			if (result instanceof JythonObjectWrapper) {
+		        result = ((JythonObjectWrapper) result)._obj;
+			} else if (result instanceof JythonHasFieldsWrapper) {
+	            result = ((JythonHasFieldsWrapper) result)._obj;
+			}
+			
+			return result;
+		} catch (PyException e) {
+			return new EvalError(e.toString());
+		}
+	}
+
+}

src/main/java/com/metaweb/gridworks/expr/JythonHasFieldsWrapper.java

@@ -0,0 +1,36 @@
+package com.metaweb.gridworks.expr;
+
+import java.util.Properties;
+
+import org.python.core.PyObject;
+import org.python.core.PyString;
+
+
+public class JythonHasFieldsWrapper extends PyObject {
+	public HasFields  _obj;
+	private Properties _bindings;
+	
+	public JythonHasFieldsWrapper(HasFields obj, Properties bindings) {
+		_obj = obj;
+		_bindings = bindings;
+	}
+	
+	public PyObject __finditem__(PyObject key) {
+		String k = (String) key.__tojava__(String.class);
+		Object v = _obj.getField(k, _bindings);
+		if (v != null) {
+			if (v instanceof HasFields)	{
+				return new JythonHasFieldsWrapper((HasFields) v, _bindings);
+			} else if (v instanceof String) {
+				return new PyString((String) v);
+			} else if (v instanceof PyObject) {
+				return (PyObject) v;
+			} else {
+				return new JythonObjectWrapper(v);
+			} 
+		} else {
+			return null;
+		}
+	}
+		
+}

src/main/java/com/metaweb/gridworks/expr/JythonObjectWrapper.java

@@ -0,0 +1,15 @@
+package com.metaweb.gridworks.expr;
+
+import org.python.core.PyObject;
+
+public class JythonObjectWrapper extends PyObject {
+	public Object  _obj;
+	
+	public JythonObjectWrapper(Object obj) {
+		_obj = obj;
+	}
+	
+	public String toString() {
+		return _obj.getClass().getSimpleName();
+	}
+}

src/main/java/com/metaweb/gridworks/expr/MetaParser.java

@@ -1,5 +1,10 @@
 package com.metaweb.gridworks.expr;
 
+import java.io.StringReader;
+import java.util.Properties;
+
+import clojure.lang.IFn;
+
 import com.metaweb.gridworks.gel.Parser;
 
 abstract public class MetaParser {
@@ -29,19 +34,17 @@ abstract public class MetaParser {
     }
     
     static protected Evaluable parseJython(String s) throws ParsingException {
-        return null;
+        return new JythonEvaluable(s);
     }
     
     static protected Evaluable parseClojure(String s) throws ParsingException {
-        
-        /*
         try {
             IFn fn = (IFn) clojure.lang.Compiler.load(new StringReader(
-                    "(fn [value row cells] " + s + ")"
+                "(fn [value cell cells row rowIndex] " + s + ")"
             ));
             
             return new Evaluable() {
-                final private IFn _fn;
+                private IFn _fn;
                 
                 public Evaluable init(IFn fn) {
                     _fn = fn;
@@ -51,9 +54,11 @@ abstract public class MetaParser {
                 public Object evaluate(Properties bindings) {
                     try {
                         return _fn.invoke(
-                            bindings.get("value"), 
+                            bindings.get("value"),
-                            bindings.get("row"), 
+                            bindings.get("cell"),
-                            bindings.get("cells")
+                            bindings.get("cells"),
+                            bindings.get("row"),
+                            bindings.get("rowIndex")
                         );
                     } catch (Exception e) {
                         return new EvalError(e.getMessage());
@@ -61,9 +66,7 @@ abstract public class MetaParser {
                 }
             }.init(fn);
         } catch (Exception e) {
-            return new ParsingException(e);
+            throw new ParsingException(e.getMessage());
         }
-        */
-        return null;
     }
 }