introduced user variables: fixes #107

Author: wumpz

src/main/java/net/sf/jsqlparser/expression/ExpressionVisitor.java

@@ -150,4 +150,6 @@ public interface ExpressionVisitor {
     void visit(JsonExpression jsonExpr);
 
 	void visit(RegExpMySQLOperator regExpMySQLOperator);
+    
+    void visit(UserVariable var);
 }

src/main/java/net/sf/jsqlparser/expression/ExpressionVisitorAdapter.java

@@ -320,4 +320,9 @@ public void visit(WithinGroupExpression wgexpr) {
             element.getExpression().accept(this);
         }
     }
+
+    @Override
+    public void visit(UserVariable var) {
+        
+    }
 }

src/main/java/net/sf/jsqlparser/expression/UserVariable.java

@@ -0,0 +1,54 @@
+/*
+ * #%L
+ * JSQLParser library
+ * %%
+ * Copyright (C) 2004 - 2013 JSQLParser
+ * %%
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as 
+ * published by the Free Software Foundation, either version 2.1 of the 
+ * License, or (at your option) any later version.
+ * 
+ * This program 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
+ * GNU General Lesser Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Lesser Public 
+ * License along with this program.  If not, see
+ * <http://www.gnu.org/licenses/lgpl-2.1.html>.
+ * #L%
+ */
+package net.sf.jsqlparser.expression;
+
+/**
+ *
+ * @author aud
+ */
+public class UserVariable implements Expression {
+
+	private String name;
+
+	/**
+	 * The name of the parameter
+	 *
+	 * @return the name of the parameter
+	 */
+	public String getName() {
+		return name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+
+	@Override
+	public void accept(ExpressionVisitor expressionVisitor) {
+		expressionVisitor.visit(this);
+	}
+
+	@Override
+	public String toString() {
+		return "@" + name;
+	}
+}

src/main/java/net/sf/jsqlparser/util/TablesNamesFinder.java

@@ -502,4 +502,8 @@ public void visit(SelectExpressionItem item) {
     @Override
     public void visit(WithinGroupExpression wgexpr) {
     }
+
+    @Override
+    public void visit(UserVariable var) {
+    }
 }

src/main/java/net/sf/jsqlparser/util/deparser/ExpressionDeParser.java

@@ -520,4 +520,9 @@ public void visit(WithinGroupExpression wgexpr) {
         buffer.append(wgexpr.toString());
     }
 
+    @Override
+    public void visit(UserVariable var) {
+        buffer.append(var.toString());
+    }
+
 }

src/main/javacc/net/sf/jsqlparser/parser/JSqlParserCC.jj

@@ -1733,6 +1733,8 @@ Expression PrimaryExpression():
 
     | retval=JdbcNamedParameter()
 
+    | retval=UserVariable()
+
 	| LOOKAHEAD(AnalyticExpression()) retval=AnalyticExpression()
 
     | LOOKAHEAD(WithinGroupExpression()) retval=WithinGroupExpression()
@@ -1788,12 +1790,23 @@ JdbcNamedParameter JdbcNamedParameter() : {
 	Token token;
 }
 {
-        ":" token=<S_IDENTIFIER> { parameter.setName(token.image); }
+    ":" token=<S_IDENTIFIER> { parameter.setName(token.image); }
 	{
 		return parameter;
 	}
 }
 
+UserVariable UserVariable() : {
+    UserVariable var = new UserVariable();
+	Token token;
+}
+{
+    "@" token=<S_IDENTIFIER> { var.setName(token.image); }
+    { 
+        return var; 
+    }
+}
+
 JsonExpression JsonExpression() : {
   JsonExpression result = new JsonExpression();
   Column column;

src/test/java/net/sf/jsqlparser/test/select/SelectTest.java

@@ -1653,4 +1653,8 @@ public void testSelectInnerWith() throws JSQLParserException {
     public void testSelectWithinGroup() throws JSQLParserException {
         assertSqlCanBeParsedAndDeparsed("SELECT LISTAGG(col1, '##') WITHIN GROUP (ORDER BY col1) FROM table1");
     }
+    
+    public void testSelectUserVariable() throws JSQLParserException {
+        assertSqlCanBeParsedAndDeparsed("SELECT @col FROM t1");
+    }
 }