Primitive Obsession Detection:
when you see:
<primitive type> variablename;
See what methods the primitive type has which are not appropriate for the domain of variablename. What does type do that variable shouldn't?
when you see:
<primitive type> variablename;
See what methods the primitive type has which are not appropriate for the domain of variablename. What does type do that variable shouldn't?
string CustomerId;
What does string do that a customer ID shouldn't?
It can be
* passed as a time zone.
* upper/lower cased.
* concatenated to/with other strings
* passed as a filename to open()
* centered in a field of spaces
* used as a format in a print statement
* searched
What does string do that a customer ID shouldn't?
It can be
* passed as a time zone.
* upper/lower cased.
* concatenated to/with other strings
* passed as a filename to open()
* centered in a field of spaces
* used as a format in a print statement
* searched
int typeCode;
It can be:
* operated upon bitwise
* used as a port number
* treated as a boolean
* multiplied/divided/added/subtracted
* overflow/underflow
* passed to so many functions!!!
It can be:
* operated upon bitwise
* used as a port number
* treated as a boolean
* multiplied/divided/added/subtracted
* overflow/underflow
* passed to so many functions!!!
Type safety is about ensuring that no operation will be applied to a variable of the wrong type.
Sometimes, a primitive type is the wrong type for a value because it allows operations to be performed on an object whose "proper" type/domain should not allow those methods.
Sometimes, a primitive type is the wrong type for a value because it allows operations to be performed on an object whose "proper" type/domain should not allow those methods.
People talk about the advantages of type-checking and the "safety" of statically-typed systems, but then they use primitive types for almost everything.
operation(int ,int ,int ,int, int, float, int, double)
Surely there is no way that anyone would possibly make a mistake calling that function, right?
Maybe if we name the parameters well, people might not?
Surely there is no way that anyone would possibly make a mistake calling that function, right?
Maybe if we name the parameters well, people might not?
What if they weren't ints and floats, but tiny classes?
I can pass the integer "class number" where the integer "student number" is expected, but I can't pass the ClassNumber 'class' where the StudentNumber 'student' is expected.
Type Safety.
Simple idea. Great idea.
I can pass the integer "class number" where the integer "student number" is expected, but I can't pass the ClassNumber 'class' where the StudentNumber 'student' is expected.
Type Safety.
Simple idea. Great idea.
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