public static JavaAST CreateToken(int type, string text = "")
{
JavaAST ast = new JavaAST();
ast.isRule = false;
ast.type = type;
if (type == -1)
{
ast.text = "";
}
else
{
var literalText = Java8Lexer._LiteralNames[type] ?? "";
if (literalText != "")
{
ast.text = literalText.Substring(1, literalText.Length - 2);
}
else
{
ast.text = text;
}
}
return(ast);
}
/// <summary>
/// Constructs the AST recursively from the ANTLR Java Parser classes.
/// </summary>
/// <param name="ctx"></param>
/// <returns></returns>
public static JavaAST ConstructAST(TerminalNodeImpl ctx)
{
if (literals.Contains(ctx.Symbol.Type))
{
return(JavaAST.CreateToken(ctx.Symbol.Type, ctx.GetText()));
}
else
{
return(JavaAST.CreateToken(ctx.Symbol.Type));
}
}
/// <summary>
/// Constructs the AST recursively from the ANTLR Java Parser classes.
/// </summary>
/// <param name="ctx"></param>
/// <returns></returns>
public static JavaAST ConstructAST(ParserRuleContext ctx)
{
if (ctx.children != null)
{
if (ctx.children.Count > 1)
{
var ast = JavaAST.CreateRule(ctx.RuleIndex);
foreach (var child in ctx.children)
{
var childCtx = child;
if (childCtx is ParserRuleContext)
{
var childAst = ConstructAST(childCtx as ParserRuleContext);
if (childAst != null)
{
ast.Children.Add(childAst);
}
}
if (childCtx is TerminalNodeImpl)
{
var childAst = ConstructAST(childCtx as TerminalNodeImpl);
if (childAst != null)
{
ast.Children.Add(childAst);
}
}
}
return(ast);
}
else if (ctx.children.Count == 1)
{
if (ctx.children[0] is ParserRuleContext)
{
return(ConstructAST(ctx.children[0] as ParserRuleContext));
}
else
{
return(ConstructAST(ctx.children[0] as TerminalNodeImpl));
}
}
else
{
return(null);
}
}
else
{
return(null);
}
}
public static JavaAST CreateRule(int type, params JavaAST[] children)
{
JavaAST ast = new JavaAST();
ast.isRule = true;
ast.type = type;
ast.text = "";
if (children != null)
{
ast.children.AddRange(children);
}
return(ast);
}
public JavaAST Parse(string filePath)
{
var code = File.ReadAllText(filePath);
var stream = CharStreams.fromString(code);
var lexer = new Java8Lexer(stream);
var tokens = new CommonTokenStream(lexer);
var parser = new Java8Parser(tokens);
parser.BuildParseTree = true;
var cu = parser.compilationUnit();
return(JavaAST.ConstructAST(cu));
}
public JavaAST Desugar(JavaAST ast)
{
if (ast == null)
{
return(null);
}
// De-sugar a basic for loop into a while loop.
//
if (ast.Rule == Java8Parser.RULE_basicForStatement)
{
return(JavaAST.CreateRule(Java8Parser.RULE_block,
JavaAST.CreateToken(Java8Lexer.LBRACE),
JavaAST.CreateRule(Java8Parser.RULE_blockStatements,
Desugar(ast.Children[2]), // for loop variable declaration
JavaAST.CreateToken(Java8Lexer.SEMI),
JavaAST.CreateRule(Java8Parser.RULE_whileStatement,
JavaAST.CreateToken(Java8Lexer.WHILE),
JavaAST.CreateToken(Java8Lexer.LPAREN),
Desugar(ast.Children[4]), // for loop condition
JavaAST.CreateToken(Java8Lexer.RPAREN),
JavaAST.CreateRule(Java8Parser.RULE_block,
JavaAST.CreateToken(Java8Lexer.LBRACE),
Desugar(ast.Children[8]), // for loop block
Desugar(ast.Children[6]), // for loop increment
JavaAST.CreateToken(Java8Lexer.SEMI),
JavaAST.CreateToken(Java8Lexer.RBRACE)
)
)
),
JavaAST.CreateToken(Java8Lexer.RBRACE)
));
}
// De-sugar a do-while loop into a while loop
//
if (ast.Rule == Java8Parser.RULE_doStatement)
{
return(JavaAST.CreateRule(Java8Parser.RULE_block,
JavaAST.CreateToken(Java8Lexer.LBRACE),
JavaAST.CreateRule(Java8Parser.RULE_blockStatements,
Desugar(ast.Children[1]), // do-while block
JavaAST.CreateToken(Java8Lexer.SEMI),
JavaAST.CreateRule(Java8Parser.RULE_whileStatement,
JavaAST.CreateToken(Java8Lexer.WHILE),
JavaAST.CreateToken(Java8Lexer.LPAREN),
Desugar(ast.Children[4]), // do-while loop condition
JavaAST.CreateToken(Java8Lexer.RPAREN),
Desugar(ast.Children[1]) // do-while block (this will be repeated under the while block
)
),
JavaAST.CreateToken(Java8Lexer.RBRACE)
));
}
// Default case: recursively desugar all children.
//
if (ast.IsRule)
{
var newChildren = new List <JavaAST>();
foreach (var child in ast.Children)
{
newChildren.Add(Desugar(child));
}
return(JavaAST.CreateRule(ast.Rule, newChildren.ToArray()));
}
else
{
return(JavaAST.CreateToken(ast.Token, ast.Text));
}
}
