// literal := INTEGER | FLOAT | TRUE | FALSE .
public ast.Expression literal() throws IOException {
ast.Expression expr = null;
if (currentToken.kind.name().equals("INTEGER")) {
expr = Command.newLiteral(expectRetrieve(Token.Kind.INTEGER));
} else if (currentToken.kind.name().equals("FLOAT")) {
expr = Command.newLiteral(expectRetrieve(Token.Kind.FLOAT));
} else if (currentToken.kind.name().equals("TRUE")) {
expr = Command.newLiteral(expectRetrieve(Token.Kind.TRUE));
} else if (currentToken.kind.name().equals("FALSE")) {
expr = Command.newLiteral(expectRetrieve(Token.Kind.FALSE));
}
return expr;
}
/*
* expression3 := "not" expression3
| "(" expression0 ")"
| designator
| call-expression
| literal .
*/
private ast.Expression expression3() throws IOException {
// TODO Auto-generated method stub
ast.Expression expr3 = null;
if (currentToken.kind.name().equals("NOT")) {
Token op = expectRetrieve(Token.Kind.NOT);
ast.Expression right = expression3();
expr3 = Command.newExpression(right, op, null);
} else if (currentToken.kind.name().equals("OPEN_PAREN")) {
accept(Token.Kind.OPEN_PAREN);
expr3 = expression0();
expect(Token.Kind.CLOSE_PAREN);
} else if (currentToken.kind.name().equals("IDENTIFIER")) {
int lineNum = currentToken.lineNumber();
int charPos = currentToken.charPosition();
ast.Expression deref = designator();
expr3 = new ast.Dereference(lineNum, charPos, deref);
} else if (currentToken.kind.name().equals("CALL")) {
expr3 = call_expression();
} else if (currentToken.kind.name().equals("INTEGER")
|| currentToken.kind.name().equals("FLOAT")
|| currentToken.kind.name().equals("TRUE")
|| currentToken.kind.name().equals("FALSE")) {
expr3 = literal();
}
return expr3;
}
// expression2 := expression3 { op2 expression3 } .
private ast.Expression expression2() throws IOException {
// TODO Auto-generated method stub
ast.Expression expr2 = null;
expr2 = expression3();
while (NonTerminal.OP2.firstSet.contains(currentToken.kind)) {
ast.Expression left = expr2;
Token op2 = op2();
ast.Expression right = expression3();
expr2 = Command.newExpression(left, op2, right);
}
return expr2;
}
// expression0 := expression1 [ op0 expression1 ] .
private ast.Expression expression0() throws IOException {
// TODO Auto-generated method stub
ast.Expression expr = null;
expr = expression1();
if (!currentToken.is(Token.Kind.SEMICOLON)) {
if (NonTerminal.OP0.firstSet.contains(currentToken.kind)) {
ast.Expression left = expr;
Token op0 = op0();
ast.Expression right = expression1();
expr = Command.newExpression(left, op0, right);
}
}
return expr;
}
// type := IDENTIFIER .
private ast.Expression type() throws IOException {
// TODO Auto-generated method stub
// expects IDENTIFIER
return Command.newLiteral(expectRetrieve(Token.Kind.IDENTIFIER));
}