private GStmt.Stmt tryStatement()
{
GStmt.Stmt tryBlock = statement();
consume(tt.CATCH, "Expect catch block after try");
GStmt.Stmt catchBlock = statement();
return(new GStmt.Try(tryBlock, catchBlock));
}
private GStmt.Stmt whileStatement()
{
consume(tt.LEFT_PAREN, "Expect '(' after 'while'");
GExpr.Expr condition = expression();
consume(tt.RIGHT_PAREN, "Expect ')' after condition");
GStmt.Stmt body = statement();
return(new GStmt.While(condition, body));
}
private GStmt.Stmt forStatement()
{
consume(tt.LEFT_PAREN, "Expect '(' after 'for'.");
GStmt.Stmt initializer;
if (Match(tt.SEMICOLON))
{
initializer = null;
}
else if (Match(tt.VAR))
{
initializer = varDeclaration();
}
else
{
initializer = expressionStatement();
}
GExpr.Expr condition = null;
if (!check(tt.SEMICOLON))
{
condition = expression();
}
consume(tt.SEMICOLON, "Expect ';' after loop condition.");
GExpr.Expr increment = null;
if (!check(tt.RIGHT_PAREN))
{
increment = expression();
}
consume(tt.RIGHT_PAREN, "Expect ')' after for clauses");
GStmt.Stmt body = statement();
if (increment != null)
{
body = new GStmt.Block(new List <GStmt.Stmt>()
{
body, new GStmt.Expression(increment)
});
}
if (condition == null)
{
condition = new GExpr.Literal(true);
}
body = new GStmt.While(condition, body);
if (initializer != null)
{
body = new GStmt.Block(new List <GStmt.Stmt>()
{
initializer, body
});
}
return(body);
}
private GStmt.Stmt ifStatement()
{
consume(tt.LEFT_PAREN, "Expect ( after 'if'");
GExpr.Expr condition = expression();
consume(tt.RIGHT_PAREN, "Expect ) after if condition.");
GStmt.Stmt thenBranch = statement();
GStmt.Stmt elseBranch = null;
if (Match(tt.ELSE))
{
elseBranch = statement();
}
return(new GStmt.If(condition, thenBranch, elseBranch));
}
private void resolve(GStmt.Stmt stmt)
{
stmt.Accept(this);
}
private void execute(GStmt.Stmt st)
{
st.Accept(this);
}
public If(Expr condition, Stmt thenBranch, Stmt elseBranch)
{
this.condition = condition;
this.thenBranch = thenBranch;
this.elseBranch = elseBranch;
}
public Try(Stmt tryStmt, Stmt catchStmt)
{
this.tryStmt = tryStmt;
this.catchStmt = catchStmt;
}
public While(Expr condition, Stmt body)
{
this.condition = condition;
this.body = body;
}
