On 2023-04-04 09:43, Jacob Kroon wrote:
Hi Jacob,
You don't need to change "var" to "const" - if you want to ensure the
variables to persist in between the function/procedure runs, you need
to move them to the global level, i.e. outside of the
functions/procedures. It is not advisable as a general practice (to
keep all variables globally), because then you might e.g. access the
same variable from multiple functions by mistake, but it would
probably solve your issue. Obviously, you might need to solve
potential conflicts if you use the same variable names in multiple
functions/procedures (e.g. by prepending the function/procedure name
to the variable name or something like that).
I could move them to global scope, and add a prefix to avoid name
collisions, but using a "const" section seems more readable to me
since I don't need to add a prefix.
The wiki page says (https://wiki.freepascal.org/Const):
"The declaration const in a Pascal program is used to inform the
compiler that certain identifiers which are being declared are
constants, that is, they are initialized with a specific value at
compile time as opposed to a variable which is initialized at run
time.
However, the default setting in Free Pascal is to allow const
identifiers to be re-assigned to."
Then it says there is a flag to make reassigning to a const variable
an error. But if I ignore that, it would seem this is just what I
need, since this seems to make the variable have a whole-program
lifetime, no ?
What is the technical downside to using "const", or is it just cosmetic
?
If you read the documentation (wiki or the real documentation in
PDF/HTML etc.) properly, you don't find there anything saying that
constants declared locally within functions or procedures are guaranteed
to keep their modified values across runs of that function/procedure. It
might behave like that, but you shouldn't rely on it unless it's a const
on a global level (and then renaming may still be needed in case of
conflicts).
Tomas
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