Marcos Douglas wrote:
On Sat, Mar 5, 2011 at 8:24 AM, Mark Morgan Lloyd
<markmll.fpc-pas...@telemetry.co.uk> wrote:
Where a unit exports an instance of an object, what's best practice for
making this read-only? I'm referring to the object reference itself here,
not properties of the object.
Where I've done this in the past I've used a function:
interface
function InitText: TFormattedString;
implementation
var xInitText: TFormattedString= nil;
function InitText: TFormattedString;
begin
result := xInitText
end { InitText } ;
Is there a better way using e.g. global properties that doesn't necessitate
both a property and an explicit function?
property InitText: TFormattedString read xInitText;
The obvious problem here is that xInitText is a forward reference to an
unexported variable.
Make a function to return a global variable does not make it read only.
If I use your function like this:
o := InitText;
o := nil; //this is the same xInitText = nil
Disagree. You are changing the value of o, not of xInitText. xInitText
is initialised once somewhere in the unit exporting it, subsequently its
properties etc. can be used elsewhere e.g. InitText.AppendFormatted(...).
--
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk
[Opinions above are the author's, not those of his employers or colleagues]
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