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placement of condition in count command 21 Oct 2021 16:25 #20044

kevclark64
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Posts: 123

In Foxpro either of the following is valid:

COUNT FOR state="CA" TO statecount
COUNT TO statecount FOR state="CA"

The X# compiler currently only allows the second construction in which the variable is named before the condition. I haven't tested it, but I wonder whether this is a general issue that might affect commands similar to COUNT.

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placement of condition in count command 21 Oct 2021 17:16 #20048

robert

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Kevin,
The X# compiler allows to freely change the order of optional clauses in user defined commands.
The COUNT command is declared as

#command COUNT TO <var>    ;
         [FOR <for>]       ;
         [WHILE <while>]   ;
         [NEXT <next>]     ;
         [RECORD <rec>]    ;
         [<rest:REST>]     ;
         [ALL]             ;
         ;
      => <var> := 0 ;
       ; DbEval( ;
                 {|| <var> := <var> + 1}, ;
                 <{for}>, <{while}>, <next>, <rec>, <.rest.> ;
               )

As you can see: the TO <var> is not optional (not between brackets) and therefore not optional.
I will see if I can tweak the command to allow TO <var> to be at the end of the command.
Making the TO <var> clause optional would technically work and allow to swap the TO and FOR clauses.
But if TO is missing then it would need to generate a compiler error.

Robert

Edit:
Maybe we can add a special notation to indicate that the "optional" clause is not really optional but can be moved around freely.
Something like this:

#command COUNT [^TO <var> ]   ;
         [FOR <for>]       ;
etc

where the ^ character would tell the preprocessor that the TO <var> clause has to be matched.

XSharp Development Team
The Netherlands

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Last edit: by robert.

placement of condition in count command 22 Oct 2021 09:38 #20075

lumberjack

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Posts: 720

Robert,

robert wrote: Kevin,
The X# compiler allows to freely change the order of optional clauses in user defined commands.

I created quickly a new count command and it seems according to the .ppo file it creates the correct output.

#command COUNT ;
         [FOR <for>]       ;
         [WHILE <while>]   ;
         [NEXT <next>]     ;
         [RECORD <rec>]    ;
         [<rest:REST>]     ;
         [ALL]             ;
         TO <var>    ;  // Note where the TO <var> is positioned
      => <var> := 0 ;
       ; DbEval( ;
                 {|| <var> := <var> + 1}, ;
                 <{for}>, <{while}>, <next>, <rec>, <.rest.> ;
               )

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Johan Nel
Boshof, South Africa

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placement of condition in count command 22 Oct 2021 09:47 #20076

robert

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Johan,
Yes that works. And it matches both

COUNT TO Var FOR SomeCondition

and

COUNT FOR SomeCondition TO Var

Why did I not think of that myself?
I will adjust the UDC in our header file
Robert

XSharp Development Team
The Netherlands

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placement of condition in count command 22 Oct 2021 09:48 #20077

robert

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Posts: 3448

Robert,
I created quickly a new count command and it seems according to the .ppo file it creates the correct output.

I use the (new) UDC Tester for this. That works very well !

Robert

XSharp Development Team
The Netherlands

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placement of condition in count command 22 Oct 2021 10:00 #20079

lumberjack

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Posts: 720

Robert,

robert wrote: I use the (new) UDC Tester for this. That works very well !

I have to apologize was not focusing on computer work the last couple of months due to my eyes, but I am feeling ready to start again.
Have downloaded the new version and will next week install and see how the next article in the Data-driven series progress.

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Johan Nel
Boshof, South Africa

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Last edit: by lumberjack.

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placement of condition in count command