Here I go again with NULL...
I recently found a bug in our code where where are checking if a passed in parameter (happens to be a DICTIONARY) to a function is null. Turns out the dictionary can never be null. This is very odd -- is that the indented behavior? I guess this is similar behavior to ARRAY?
MAIN
CALL check_dictionary(NULL)
END MAIN
FUNCTION check_dictionary(dict)
DEFINE dict DICTIONARY OF STRING
DISPLAY "Passed in Dictionary"
IF dict IS NULL THEN
DISPLAY "dict IS NULL"
ELSE
DISPLAY "dict IS NOT NULL"
END IF
DISPLAY ""
DISPLAY "LET dict = NULL"
LET dict = NULL
IF dict IS NULL THEN
DISPLAY "dict IS NULL"
ELSE
DISPLAY "dict IS NOT NULL"
END IF
DISPLAY ""
DISPLAY "INITIALIZE dict to NULL"
INITIALIZE dict TO NULL
IF dict IS NULL THEN
DISPLAY "dict IS NULL"
ELSE
DISPLAY "dict IS NOT NULL"
END IF
END FUNCTION
Output:
Passed in Dictionary
dict IS NOT NULL
LET dict = NULL
dict IS NOT NULL
INITIALIZE dict to NULL
dict IS NOT NULL
According to the documentation the DICTIONARY array is passed to/from functions by reference on the stack and not by value. Use the getLength() method to check if the dictionary is empty.
On the subject of DICTIONARY it would be nice to have the option to sort them into key order...
I am surprised that "IF dict IS NULL" compiles. I would expect similar to "IF arr IS NULL" which generate a -4340 error, and that the correct test would be "IF dict.getLength() = 0" just like dynamic array case "IF arr.getlength() = 0".
QuoteOn the subject of DICTIONARY it would be nice to have the option to sort them into key order...
Just sort the keys array.
LET keys = dict.getkeys()
CALL keys.sort(NULL, FALSE)
Hello,
In upcoming FGL versions 3.10.18 and FGL 3.20.04 (this is not in 3.20 EAP3!), the compiler will raise the error -4340 when using a dictionary in expressions like IF dict IS NULL THEN:
MAIN
DEFINE dict DICTIONARY OF STRING
IF dict IS NULL THEN
| The variable 'dict' is too complex a type to be used in an expression.
| See error number -4340.
DISPLAY "dict IS NULL"
ELSE
DISPLAY "dict IS NOT NULL"
END IF
END MAIN
Seb
Quote from: Reuben B. on May 09, 2019, 01:24:10 AM
Just sort the keys array.
Good point, I forgot about that one! Thanks.