[fpc-pascal] specify variable name with string variable

[James Richters]

Thank you, using fgl;  did work.

Am I correct in assuming that if I want other types of Variables I would change PWord in 
specialize TFPGMap<String, PWord>;
to something else, maybe PString, PDouble, PLongint.... etc?


James

-----Original Message-----
From: fpc-pascal <fpc-pascal-bounces at lists.freepascal.org> On Behalf Of Stefan V. Pantazi
Sent: Monday, July 8, 2019 10:54 AM
To: fpc-pascal at lists.freepascal.org
Subject: Re: [fpc-pascal] specify variable name with string variable

You can use the TFPGMap class in fgl unit to implement the dictionary. 
fgl should be available in 3.0.4. Try to replace the Generics.Collections with fgl and the type definition in the example code from zh loza. The rest should be identical.

[...]

uses fgl;

type

TVariableDictionary = specialize TFPGMap<String, PWord>;

[...]


On 7/8/19 8:09 AM, James Richters wrote:
> I'm on windows....
> 
> Generics.Collections seems to be something that was added after 3.0.4,  I've downloaded the current FPC source code, but I’m not sure how to build it.. can someone point me in the right direction on how to compile the current source code?
> 
> James
> -----Original Message-----
> From: fpc-pascal <fpc-pascal-bounces at lists.freepascal.org> On Behalf 
> Of James Richters
> Sent: Monday, July 8, 2019 6:48 AM
> To: 'FPC-Pascal users discussions' <fpc-pascal at lists.freepascal.org>
> Subject: Re: [fpc-pascal] specify variable name with string variable
> 
> Thank you for the answer and the example... I didn't know there was such a thing as a variable dictionary, but It looks like that may work for me, I'll give it a try!
> 
> James
> -----Original Message-----
> From: fpc-pascal <fpc-pascal-bounces at lists.freepascal.org> On Behalf 
> Of zh loza
> Sent: Sunday, July 7, 2019 4:34 PM
> To: FPC-Pascal users discussions <fpc-pascal at lists.freepascal.org>
> Subject: Re: [fpc-pascal] specify variable name with string variable
> 
> Hi all! It's my first answer to the mailing list, hopefully I won't screw anything up.
> 
> On Sun, Jul 7, 2019 at 10:58 PM James Richters <james at productionautomation.net> wrote:
>>
>> This might sound silly,  but is it possible to somehow specify a variable with a string containing the name of the variable?
> 
> You might want to try using generic dictionaries. E.g. like this:
> 
> program Project1;
> uses
>    SysUtils, Generics.Collections;
> 
> type
>    TVariableDictionary = specialize TDictionary<String, PWord>;
> 
> var
>    MyDictionary: TVariableDictionary;
>    MyVariable1: Word;
> 
> begin
>    MyDictionary := TVariableDictionary.Create;
>    MyDictionary.Add('MyVariable1', @MyVariable1);
>    MyDictionary['MyVariable1']^ := 100;
>    WriteLn(MyVariable1);
>    WriteLn(MyDictionary['MyVariable1']^);
>    FreeAndNil(MyDictionary);
> end.
> 
> If you need to address variables of different type, try Variants ( https://wiki.freepascal.org/Variant ).
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