/// <summary>
/// ClassStmt
/// CLASS ID LBRACES DeclarationStmt* RBRACES
/// </summary>
/// <returns></returns>
private ClassStmt ParseClassStmt()
{
Consume(TokenType.CLASS);
ClassStmt ret = new ClassStmt(Consume(TokenType.ID).Literal);
FuncStmt fs = null;
FuncStmt fcur = null;
VarStmt vs = null;
VarStmt vcur = null;
Consume(TokenType.LBRACES);
while (!Check(TokenType.RBRACES))
{
DeclarationStmt stmt = ParseDeclOrDefStmt();
if (stmt is FuncStmt)
{
AppendASTLinkedList(ref fs, ref fcur, (FuncStmt)stmt);
}
else
{
AppendASTLinkedList(ref vs, ref vcur, (VarStmt)stmt);
}
}
Consume(TokenType.RBRACES);
ret.Methods = fs;
ret.Fields = vs;
return(ret);
}
/// <summary>
/// Params
/// TypeExpr Id (COMMA Params)?
/// </summary>
/// <returns></returns>
private VarStmt ParseParams()
{
TypeExpr type = ParseTypeExpr();
IdExpr id = ParseId();
VarStmt vars = new VarStmt(AccessFlag.DefaultFlag, type, id.Id, null);
if (Check(TokenType.COMMA))
{
Consume(TokenType.COMMA);
vars.SiblingAST = ParseParams();
}
return(vars);
}
/// <summary>
/// 这里用了LookAhead
/// 此外不允许不带定义的声明
/// DeclarationStmt
/// ACCESS_FLAG* TypeExpr FuncDeclarator BlockStmt
/// ACCESS_FLAG* TypeExpr VarDeclarator SEMICOLON
/// </summary>
/// <returns></returns>
private DeclarationStmt ParseDeclOrDefStmt()
{
AccessFlag flag = ParserAccessFlag();
TypeExpr type = ParseTypeExpr();
if (Check(TokenType.LPAREN) || CheckAt(1, TokenType.LPAREN))
{
FuncStmt ret = ParseFuncDeclarator(type, flag);
ret.Body = ParseBlockStmt();
return(ret);
}
else
{
VarStmt ret = ParseVarDeclarator(type, flag);
Consume(TokenType.SEMICOLON);
return(ret);
}
}
/// <summary>
/// VarDeclarator
/// Id (ASSIGN Expr)? (COMMA VarDeclarator)?
/// </summary>
/// <param name="flag"></param>
/// <param name="type"></param>
/// <returns></returns>
private VarStmt ParseVarDeclarator(TypeExpr type, AccessFlag flag)
{
Expr declarator = ParseExpr(true);
VarStmt vars;
if (declarator is IdExpr idExpr)
{
vars = new VarStmt(flag, type, idExpr.Id, null);
}
else
{
vars = new VarStmt(flag, type, ((IdExpr)declarator.Expr1).Id, declarator.Expr2);
}
if (Check(TokenType.COMMA))
{
Consume(TokenType.COMMA);
vars.SiblingAST = ParseVarDeclarator(type, flag);
}
return(vars);
}
