[fpc-devel] Incomplete docs on operator precedence / Question about actual precedence
DrDiettrich1 at aol.com
Mon Feb 3 10:42:04 CET 2014
Martin Frb schrieb:
> Further, it appears that ^ has a higher precedence than unary -
IMO pointer/address arithmetic (should) follows its own rules.
Unary - and @ should not be applicable to addresses. @ also is
restricted to arguments which *do* have an address, i.e. not applicable
to arithmetic expressions or properties.
Applicable binary operators depend on the type of both arguments, e.g.
it's valid to subtract addresses (yielding an ordinal value), but adding
addresses should be disallowed, while adding an ordinal value to an
pointer is okay (yealding another address).
> // p:= - at i; // if enabled, next line will crash
This should not compile, unary - is not applicable to addresses.
> writeln( -p^ ); // writes -99
Here ^ must take precedence, applied to an pointer/address.
"p+i^" is questionable, the only valid interpretation is (p+i)^.
IOW applicable operators and precedence depend on the type of the
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