private Statement parseStatement()
{
// Bloque
if (token.TokenType == TokenType.LLAVEI)
{
entornoActual = new Entorno(entornoActual);
eat(TokenType.LLAVEI);
// recursively call parseStatement() until closing brace
StatementList stms = new StatementList();
while (token.TokenType != TokenType.LLAVED && token.TokenType != TokenType.EOF)
{
stms.addElement(parseStatement());
}
eat(TokenType.LLAVED);
entornoActual = entornoActual.Anterior;
return(new Block(stms, entornoActual));
}
switch (token.TokenType)
{
case TokenType.PUNTOYCOMA:
eat(TokenType.PUNTOYCOMA);
return(Statement.Null);
case TokenType.IF:
eat(TokenType.IF);
// parse conditional expression
eat(TokenType.IPAREN);
Exp condExp = parseExpression();
eat(TokenType.DPAREN);
Statement trueStm = parseStatement();
if (token.TokenType != TokenType.ELSE)
{
return(new If(condExp, trueStm));
}
eat(TokenType.ELSE);
Statement falseStm = parseStatement();
return(new Else(condExp, trueStm, falseStm));
case TokenType.WHILE:
eat(TokenType.WHILE);
eat(TokenType.IPAREN);
Exp x = parseExpression();
eat(TokenType.DPAREN);
Statement loopStm = parseStatement();
While nodowhile = new While(x, loopStm);
return(nodowhile);
case TokenType.DO:
eat(TokenType.DO);
Statement loopStnm = parseStatement();
eat(TokenType.WHILE);
eat(TokenType.IPAREN);
Exp bulcleBody = parseExpression();
eat(TokenType.DPAREN);
eat(TokenType.PUNTOYCOMA);
return(new Do(loopStnm, bulcleBody));
case TokenType.FOR:
entornoActual = new Entorno(entornoActual); // Crera un nuevo entorno para el bucle for
eat(TokenType.FOR);
eat(TokenType.IPAREN);
Statement declararion;
if (token.TokenType != TokenType.ident)
{
declararion = parseVarDecl();
}
else
{
declararion = Asignar();
}
Exp loopExpr = parseExpression();
eat(TokenType.PUNTOYCOMA);
Asignacion incExpr = Asignar(bucleFor: true);
eat(TokenType.DPAREN);
Statement stm = parseStatement();
entornoActual = entornoActual.Anterior;
return(new For(declararion, loopExpr, incExpr, stm));
case TokenType.ident:
if (token.Lexeme == "System")
{
eat(TokenType.ident);
eat(TokenType.PUNTO);
if (token.Lexeme != "out")
{
error("Se esperaba out");
}
eat(TokenType.ident);
eat(TokenType.PUNTO);
if (token.Lexeme != "println")
{
error("Se esperaba out");
}
eat(TokenType.ident);
eat(TokenType.IPAREN);
Exp expresion = parseExpression();
eat(TokenType.DPAREN);
return(new Print(expresion));
}
return(Asignar());
}
switch (token.TokenType)
{
// int and boolean signals start of var declaration
case TokenType.INT:
return(parseVarDecl());
case TokenType.BOOLEAN:
return(parseVarDecl());
case TokenType.FLOAT:
return(parseVarDecl());
case TokenType.STRING:
return(parseVarDecl());
case TokenType.CHAR:
return(parseVarDecl());
case TokenType.DOUBLE:
return(parseVarDecl());
}
// statement type unknown
error("Error no se esperaba " + token.TokenType);
return(null);
}
