C#, ANTLR, ECMAScript grammar troubles - antlr3

Question

I'm trying to parse JavaScript (ECMASCript) with C#.
I found the following instruction on how to create new project:
http://www.antlr.org/wiki/pages/viewpage.action?pageId=557075
So I've downloaded ANTLRWorks, ANTLR v3, unpacked ANTLR, created a VS2010 project (.NET4), added references, checked and generated the grammar.
Then I recieved a lot of compilation error:
The type or namespace name 'AstParserRuleReturnScope' could not be found (are you missing a using directive or an assembly reference?)
The type or namespace name 'GrammarRule' could not be found (are you missing a using directive or an assembly reference?)
Stackoverlowed for them and got a solution: antlr c# errors when integrating into VS2008
So I've downloaded new runtime, overwrite the old one and recompiled the project and got
The name 'HIDDEN' does not exist in the current context d:\Workspace.1\ScriptParser\ScriptParser\TestLexer.cs
Ok, I've changed HIDDEN to Hidden as recommended at in the following conversation: [antlr-interest] How viable is the Csharp3 target? (more specific questions)
Now I'm trying to parse the input. I found a few examples and wrote the following code:
using Antlr.Runtime;
namespace ScriptParser
{
class Program
{
static void Main(string[] args)
{
var stream = new ANTLRStringStream("1+2");
var lexer = new TestLexer(stream);
var tokenStream = new CommonTokenStream(lexer);
var parser = new TestParser(tokenStream);
// what exactly should be here???
}
}
}
My goal is to parser JavaScript file with ANTLR but it seems that it will be the not as easy as I thought...
Update:
As suggested in Why are antlr3 c# parser methods private? I've modified the Test.g grammar by adding the "public" modified before the expr rule:
public expr : mexpr (PLUS^ mexpr)* SEMI!
;
and then regenerated the code, replaced HIDDEN to Hidden (again) and modified the code as follows:
var stream = new ANTLRStringStream("1+2");
var lexer = new TestLexer(stream);
var tokenStream = new CommonTokenStream(lexer);
var parser = new TestParser(tokenStream);
var result = parser.expr();
var tree = (CommonTree)result.Tree;
And not it is crashing on the line
root_0 = (object)adaptor.Nil();
in the following generated code
try { DebugEnterRule(GrammarFileName, "expr");
DebugLocation(7, 0);
try
{
// d:\\Workspace.1\\ScriptParser\\ScriptParser\\Test.g:7:13: ( mexpr ( PLUS ^ mexpr )* SEMI !)
DebugEnterAlt(1);
// d:\\Workspace.1\\ScriptParser\\ScriptParser\\Test.g:7:15: mexpr ( PLUS ^ mexpr )* SEMI !
{
root_0 = (object)adaptor.Nil();
DebugLocation(7, 15);
PushFollow(Follow._mexpr_in_expr31);
with the NullReferenceException message because the adapter is null.
I've resolved it by adding
parser.TreeAdaptor = new CommonTreeAdaptor();
Update 2:
So, finally I've started with my primary task: parse JavaScript.
ANTLR highlights the ECMAScript grammar by Chris Lambrou.
So I've generated lexer/parser and run it with the very simple JavaScript code:
var f = function () { };
and the parsing fails with the following output from tree.ToStringTree():
<error: var q = function () { };>

Answer 1

Your grammar rule says that there should be a semicolon at the end of the expression, but in you main function:
var stream = new ANTLRStringStream("1+2");
is missing a semicolon. Shouldn't it be "1+2;"?