Implemented a meta parser that looks for a language prefix and picks the right parser.

git-svn-id: http://google-refine.googlecode.com/svn/trunk@159 7d457c2a-affb-35e4-300a-418c747d4874

src/main/java/com/metaweb/gridworks/browsing/facets/ListFacet.java

@@ -14,7 +14,7 @@ import com.metaweb.gridworks.browsing.FilteredRows;
 import com.metaweb.gridworks.browsing.filters.ExpressionEqualRowFilter;
 import com.metaweb.gridworks.browsing.filters.RowFilter;
 import com.metaweb.gridworks.expr.Evaluable;
-import com.metaweb.gridworks.gel.Parser;
+import com.metaweb.gridworks.expr.MetaParser;
 import com.metaweb.gridworks.model.Project;
 
 public class ListFacet implements Facet {
@@ -74,7 +74,7 @@ public class ListFacet implements Facet {
 		_columnName = o.getString("columnName");
 		_cellIndex = project.columnModel.getColumnByName(_columnName).getCellIndex();
 		
-		_eval = new Parser(_expression).getExpression();
+		_eval = MetaParser.parse(_expression);
 		_selection.clear();
 		
 		JSONArray a = o.getJSONArray("selection");

src/main/java/com/metaweb/gridworks/browsing/facets/RangeFacet.java

@@ -10,7 +10,7 @@ import com.metaweb.gridworks.browsing.FilteredRows;
 import com.metaweb.gridworks.browsing.filters.ExpressionNumberComparisonRowFilter;
 import com.metaweb.gridworks.browsing.filters.RowFilter;
 import com.metaweb.gridworks.expr.Evaluable;
-import com.metaweb.gridworks.gel.Parser;
+import com.metaweb.gridworks.expr.MetaParser;
 import com.metaweb.gridworks.model.Column;
 import com.metaweb.gridworks.model.Project;
 
@@ -80,7 +80,7 @@ public class RangeFacet implements Facet {
 		_columnName = o.getString("columnName");
 		_cellIndex = project.columnModel.getColumnByName(_columnName).getCellIndex();
 		
-		_eval = new Parser(_expression).getExpression();
+		_eval = MetaParser.parse(_expression);
 		
 		_mode = o.getString("mode");
 		if ("min".equals(_mode)) {

src/main/java/com/metaweb/gridworks/commands/util/PreviewExpressionCommand.java

@@ -16,8 +16,8 @@ import com.metaweb.gridworks.expr.EvalError;
 import com.metaweb.gridworks.expr.Evaluable;
 import com.metaweb.gridworks.expr.ExpressionUtils;
 import com.metaweb.gridworks.expr.HasFields;
+import com.metaweb.gridworks.expr.MetaParser;
 import com.metaweb.gridworks.expr.ParsingException;
-import com.metaweb.gridworks.gel.Parser;
 import com.metaweb.gridworks.model.Cell;
 import com.metaweb.gridworks.model.Project;
 import com.metaweb.gridworks.model.Row;
@@ -50,7 +50,7 @@ public class PreviewExpressionCommand extends Command {
 			writer.object();
 			
 			try {
-				Evaluable eval = new Parser(expression).getExpression();
+				Evaluable eval = MetaParser.parse(expression);
 				
 				writer.key("code"); writer.value("ok");
 				writer.key("results"); writer.array();

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

@@ -0,0 +1,69 @@
+package com.metaweb.gridworks.expr;
+
+import com.metaweb.gridworks.gel.Parser;
+
+abstract public class MetaParser {
+    static public Evaluable parse(String s) throws ParsingException {
+        String language = "gel";
+        
+        int colon = s.indexOf(':');
+        if (colon >= 0) {
+            language = s.substring(0, colon);
+        }
+        
+        if ("jython".equalsIgnoreCase(language)) {
+            return parseJython(s.substring(colon + 1));
+        } else if ("clojure".equalsIgnoreCase(language)) {
+            return parseClojure(s.substring(colon + 1));
+        } else if ("gel".equalsIgnoreCase(language)) {
+            return parseGEL(s.substring(colon + 1));
+        } else {
+            return parseGEL(s);
+        }
+    }
+    
+    static protected Evaluable parseGEL(String s) throws ParsingException {
+        Parser parser = new Parser(s);
+        
+        return parser.getExpression();
+    }
+    
+    static protected Evaluable parseJython(String s) throws ParsingException {
+        return null;
+    }
+    
+    static protected Evaluable parseClojure(String s) throws ParsingException {
+        
+        /*
+        try {
+            IFn fn = (IFn) clojure.lang.Compiler.load(new StringReader(
+                    "(fn [value row cells] " + s + ")"
+            ));
+            
+            return new Evaluable() {
+                final private IFn _fn;
+                
+                public Evaluable init(IFn fn) {
+                    _fn = fn;
+                    return this;
+                }
+                
+                public Object evaluate(Properties bindings) {
+                    try {
+                        return _fn.invoke(
+                            bindings.get("value"), 
+                            bindings.get("row"), 
+                            bindings.get("cells")
+                        );
+                    } catch (Exception e) {
+                        return new EvalError(e.getMessage());
+                    }
+                }
+            }.init(fn);
+        } catch (Exception e) {
+            return new ParsingException(e);
+        }
+        */
+        return null;
+    }
+}

src/main/java/com/metaweb/gridworks/operations/ColumnAdditionOperation.java

@@ -13,7 +13,7 @@ import com.metaweb.gridworks.browsing.FilteredRows;
 import com.metaweb.gridworks.browsing.RowVisitor;
 import com.metaweb.gridworks.expr.Evaluable;
 import com.metaweb.gridworks.expr.ExpressionUtils;
-import com.metaweb.gridworks.gel.Parser;
+import com.metaweb.gridworks.expr.MetaParser;
 import com.metaweb.gridworks.history.Change;
 import com.metaweb.gridworks.history.HistoryEntry;
 import com.metaweb.gridworks.model.AbstractOperation;
@@ -113,7 +113,7 @@ public class ColumnAdditionOperation extends EngineDependentOperation {
 	protected RowVisitor createRowVisitor(Project project, List<CellAtRow> cellsAtRows) throws Exception {
 		Column column = project.columnModel.getColumnByName(_baseColumnName);
 		
-		Evaluable eval = new Parser(_expression).getExpression();
+		Evaluable eval = MetaParser.parse(_expression);
         Properties bindings = ExpressionUtils.createBindings(project);
         
 		return new RowVisitor() {

src/main/java/com/metaweb/gridworks/operations/TextTransformOperation.java

@@ -10,7 +10,7 @@ import org.json.JSONWriter;
 import com.metaweb.gridworks.browsing.RowVisitor;
 import com.metaweb.gridworks.expr.Evaluable;
 import com.metaweb.gridworks.expr.ExpressionUtils;
-import com.metaweb.gridworks.gel.Parser;
+import com.metaweb.gridworks.expr.MetaParser;
 import com.metaweb.gridworks.model.AbstractOperation;
 import com.metaweb.gridworks.model.Cell;
 import com.metaweb.gridworks.model.Column;
@@ -64,7 +64,7 @@ public class TextTransformOperation extends EngineDependentMassCellOperation {
 	protected RowVisitor createRowVisitor(Project project, List<CellChange> cellChanges) throws Exception {
 		Column column = project.columnModel.getColumnByName(_columnName);
 		
-		Evaluable eval = new Parser(_expression).getExpression();
+		Evaluable eval = MetaParser.parse(_expression);
         Properties bindings = ExpressionUtils.createBindings(project);
         
 		return new RowVisitor() {