[fpc-pascal] question about class

spir ☣ denis.spir at gmail.com
Sat May 15 00:29:46 CEST 2010


Hello,

I'm trying to transform a manually implemented type, with pseudo-method as funcs/procs, into an fpc "class" type; and facing numerous issue: namely 3 whole pages of compiler errors ;-).
Are there somewhere more or less pedagogic examples of class code?

*self*
Do i need to explicitely name self as param? Is self actually a pointer? If yes, do I need to treat as such, or is this magically handled by the language? Eg self^.prop or self.prop?

*destructor*
Is a destructor required? What is it supposed to do? Deallocation? (but then self disappears in the middle of a method it is the target of...). Isn't it garbage collected when dereferenced?

*type mutual recursion*
One func method returns an object of another type (actualy a record, but I guess it does not make any difference). But this record object holds a pointer to an object of the first type... Similar issue with a param of another method. There was no issue in the non-class version of the same code, since pseudo-methods (and their params and return values) did not need to be pre-declared.
By the way: why do we need to pre-declare methods, since they are bound to their type anyway by their name prefixes? (I mean so-called "qualified names" of the form type.methodName).

Denis
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