ANTLR: help needed with custom interpreter - antlr

Question

I have some problems with "gathering" the data. It seems my code knows how to visit each tree and calculate values correctly but something is missing as the result is always null. Help is appreciated.
.g4 file:
grammar MyParser;
ID: [a-z]+ ;
Operator_I: '&';
Operator_U: '|';
EQ: '=';
expr: '(' expr ')' #wParExpr
| expr op=(Operator_I | Operator_U) expr #wExpr
| ID wID
;
corr: 'C=' (expr)* #Result;
.java code
import org.antlr.v4.runtime.misc.NotNull;
import org.antlr.v4.runtime.tree.TerminalNode;
import java.util.*;
public class EvalVisitor extends MyParserBaseVisitor<Value> {
#Override
public Value visitWParExpr(MyParserParser.WParExprContext ctx) {
// TODO Auto-generated method stub
System.out.println("visitWParExpr:"+ctx.getText());
return visitChildren(ctx);
}
#Override
public Value visitWID(MyParserParser.WIDContext ctx) {
// TODO Auto-generated method stub
System.out.println("id:"+ctx.getText());
String id=ctx.getText();
Value v = getMemory().get(id);
l("ret id:"+v.value);
return v;
}
#Override
public Value visitWExpr(MyParserParser.WExprContext ctx) {
String left=ctx.expr(0).getText();
String right=ctx.expr(1).getText();
if (ctx.getText().contains("(")) {
return visitChildren(ctx);
}
l("visitWExpr, left="+left+",right:"+right);
String op=ctx.op.getText();
Value lefti = visit(ctx.expr(0));
Value righti = visit(ctx.expr(1));;
Value v= null;
if (op.equals("&")) {
v=new Value(lefti.asDouble()+righti.asDouble());
} else if (op.equals("|")) {
v=new Value(lefti.asDouble()+righti.asDouble());
}
l("return:"+v.asString());
return v;
}
public void l(String log) {
System.out.println(log);
}
#Override public Value visitResult(MyParserParser.ResultContext ctx) {
String s1 = ctx.getText();
String s2 = ctx.expr(0).getText();
l("VisitResult:"+s1+", expr="+s2);
Value v = visit(ctx.expr(0));
l("VisitResult end:"+v);
memory.put("result",v);
return v;
}
private Map<String, Value> memory = new HashMap<String, Value>();
public EvalVisitor() {
getMemory().put("a", new Value(new Double(5)));
getMemory().put("b", new Value(new Double(9)));
getMemory().put("c", new Value(new Double(12)));
}
public Map<String, Value> getMemory() {
return memory;
}
public void setValues(Map<String, Value> values) {
this.memory = values;
}
}
public static void main(String[] args) throws Exception {
MyParserLexer lexer = new MyParserLexer(new ANTLRFileStream("c:\\test.mu"));
MyParserParser parser = new MyParserParser(new CommonTokenStream(lexer));
ParseTree tree = parser.corr();
EvalVisitor visitor = new EvalVisitor();
visitor.visit(tree);
System.out.println(visitor.getMemory());
}
output:
VisitResult:C=(a&b)&(b&c)|(c&c), expr=(a&b)&(b&c)|(c&c)
visitWParExpr:(a&b)
visitWExpr, left=a,right:b
id:a
ret id:5.0
id:b
ret id:9.0
return:14.0
visitWParExpr:(b&c)
visitWExpr, left=b,right:c
id:b
ret id:9.0
id:c
ret id:12.0
return:21.0
visitWParExpr:(c&c)
visitWExpr, left=c,right:c
id:c
ret id:12.0
id:c
ret id:12.0
return:24.0
VisitResult end:null
{result=null, a=5.0, b=9.0, c=12.0}
EDIT
I think I got it working. The reason was that I did not do evaluations in wExpr context. I didn't understand that I need to evaluate subtrees (if context contains "(") there unless I have only id available which resolves down to double value.
Can this same be achieved in more efficient manner or implement the same functionality some other way ? For example is it possible to do this if I had only one expr() function that gets all the expressions ?
Here's revised code if someone is interested:
import org.antlr.v4.runtime.misc.NotNull;
import org.antlr.v4.runtime.tree.TerminalNode;
import java.util.*;
public class EvalVisitor extends MyParserBaseVisitor<Value> {
#Override
public Value visitWParExpr(MyParserParser.WParExprContext ctx) {
// TODO Auto-generated method stub
System.out.println("visitWParExpr:"+ctx.getText()+", expr:"+ctx.expr().getText());
String expr= ctx.expr().getText();
Value v = visit(ctx.expr());
l("WParExpr:"+v);
memory.put(expr, v);
return v;
}
#Override
public Value visitWID(MyParserParser.WIDContext ctx) {
// TODO Auto-generated method stub
System.out.println("VisitWID:"+ctx.getText());
String id=ctx.getText();
Value v = getMemory().get(id);
l("ret id:"+v.value);
return v;
}
#Override
public Value visitWExpr(MyParserParser.WExprContext ctx) {
String left=ctx.expr(0).getText();
String right=ctx.expr(1).getText();
l("visitWExpr:"+ctx.getText()+", left="+left+",right:"+right);
Value v=null;
Value lv=null;
Value rv=null;
if (ctx.getText().contains("(")) {
lv = visit(ctx.expr(0));
rv = visit(ctx.expr(1));
} else {
lv = visit(ctx.expr(0));
rv = visit(ctx.expr(1));;
}
String op=ctx.op.getText();
l("lv="+lv+",rv="+rv+",op="+op);
if (op.equals("&")) {
v=new Value(lv.asDouble()+rv.asDouble());
} else if (op.equals("|")) {
v=new Value(lv.asDouble()*rv.asDouble());
}
l("return:"+v.asString());
return v;
}
public void l(String log) {
System.out.println(log);
}
#Override public Value visitResult(MyParserParser.ResultContext ctx) {
String s1 = ctx.getText();
String s2 = ctx.expr().getText();
l("VisitResult:"+s1+", expr="+s2);
Value v = visit(ctx.expr());
l("VisitResult end:"+v);
memory.put("result",v);
return v;
}
private Map<String, Value> memory = new HashMap<String, Value>();
public EvalVisitor() {
getMemory().put("a", new Value(new Double(5)));
getMemory().put("b", new Value(new Double(9)));
getMemory().put("c", new Value(new Double(12)));
}
public Map<String, Value> getMemory() {
return memory;
}
public void setValues(Map<String, Value> values) {
this.memory = values;
}
}
Sample output for: string:
C=((a&b)&(b&c))|(c&c)|((b&a)&(c&b))|(c|c)
VisitResult:C=((a&b)&(b&c))|(c&c)|((b&a)&(c&b))|(c|c), expr=((a&b)&(b&c))|(c&c)|((b&a)&(c&b))|(c|c)
visitWExpr:((a&b)&(b&c))|(c&c)|((b&a)&(c&b))|(c|c), left=((a&b)&(b&c))|(c&c)|((b&a)&(c&b)),right:(c|c)
visitWExpr:((a&b)&(b&c))|(c&c)|((b&a)&(c&b)), left=((a&b)&(b&c))|(c&c),right:((b&a)&(c&b))
visitWExpr:((a&b)&(b&c))|(c&c), left=((a&b)&(b&c)),right:(c&c)
visitWParExpr:((a&b)&(b&c)), expr:(a&b)&(b&c)
visitWExpr:(a&b)&(b&c), left=(a&b),right:(b&c)
visitWParExpr:(a&b), expr:a&b
visitWExpr:a&b, left=a,right:b
VisitWID:a
ret id:5.0
VisitWID:b
ret id:9.0
lv=5.0,rv=9.0,op=&
return:14.0
WParExpr:14.0
visitWParExpr:(b&c), expr:b&c
visitWExpr:b&c, left=b,right:c
VisitWID:b
ret id:9.0
VisitWID:c
ret id:12.0
lv=9.0,rv=12.0,op=&
return:21.0
WParExpr:21.0
lv=14.0,rv=21.0,op=&
return:35.0
WParExpr:35.0
visitWParExpr:(c&c), expr:c&c
visitWExpr:c&c, left=c,right:c
VisitWID:c
ret id:12.0
VisitWID:c
ret id:12.0
lv=12.0,rv=12.0,op=&
return:24.0
WParExpr:24.0
lv=35.0,rv=24.0,op=|
return:840.0
visitWParExpr:((b&a)&(c&b)), expr:(b&a)&(c&b)
visitWExpr:(b&a)&(c&b), left=(b&a),right:(c&b)
visitWParExpr:(b&a), expr:b&a
visitWExpr:b&a, left=b,right:a
VisitWID:b
ret id:9.0
VisitWID:a
ret id:5.0
lv=9.0,rv=5.0,op=&
return:14.0
WParExpr:14.0
visitWParExpr:(c&b), expr:c&b
visitWExpr:c&b, left=c,right:b
VisitWID:c
ret id:12.0
VisitWID:b
ret id:9.0
lv=12.0,rv=9.0,op=&
return:21.0
WParExpr:21.0
lv=14.0,rv=21.0,op=&
return:35.0
WParExpr:35.0
lv=840.0,rv=35.0,op=|
return:29400.0
visitWParExpr:(c|c), expr:c|c
visitWExpr:c|c, left=c,right:c
VisitWID:c
ret id:12.0
VisitWID:c
ret id:12.0
lv=12.0,rv=12.0,op=|
return:144.0
WParExpr:144.0
lv=29400.0,rv=144.0,op=|
return:4233600.0
VisitResult end:4233600.0
{result=4233600.0, a=5.0, c&c=24.0, b=9.0, c=12.0, (a&b)&(b&c)=35.0, c|c=144.0, a&b=14.0, b&a=14.0, (b&a)&(c&b)=35.0, b&c=21.0, c&b=21.0}