Cobol - Can I get COBOL to look in a mirror?...

Author

Can I get COBOL to look in a mirror?...

Kellie Fitton

2005-04-24, 8:55 am

Hello Everyone,

I posted this question last sunday in the afternoon, but for some
reason or another, google.com never posted my question on the
C.L.C group, I don't know why. Lets try again.

I want to compare between two fonts and choose one of them as the
default font of my graphical window ---- so I have to make two
consecutive calls into the win32 API's, and retrieve the needed
informations about both fonts in a pre-defined font structure.

Classically, I would make one call to collect the first set of
information about the first font, move these information from the
array and into a temporary holding storage area (working storage),
before I can make another call to get the second set of
information about the second font respectively.

Alternatively, I could duplicate the fonts structure and assign
a different name for each array, make the calls successively and
analyze the contents of both arrays to determine the difference.
however, I would like to propose a new wrinkle for a pipeDream,
that should eliminate the duplicate codes, and the superfluous
steps aforeMentioned to solve this comparison dilemma.

First, I would declare two variables as pointers to the same font
structure in the linkage & local-storage section, implement the
win32 API's calls as recursive functions, which should force the
runtime system to automatically, generate a separate mirror image
of the font structure for each subsequent call. Nonetheless, the
main hurdle with this strategy is: How to reference each mirror
image when evaluating between the members of the two structures??.

Please consider the following skeleton program to understand what
I am talking about. Hopefully, you have a rabbit in a hat or
perhaps a tweak to efficiently optimize this function.

Regards, Kellie.

*>------- Cobol comparison function -------<*

Identification Division.
program-ID. Mirror.
author. Kellie Fitton.

Working-Storage Section.
01 TEXTMETRIC is typeDef.
02 tmHeight LONG.
02 tmAscent LONG.
02 tmDescent LONG.
02 tmInternalLeading LONG.
02 tmExternalLeading LONG.
02 tmAveCharWidth LONG.
02 tmMaxCharWidth LONG.
02 tmWeight LONG.
02 tmOverhang LONG.
02 tmDigitizedAspectX LONG.
02 tmDigitizedAspectY LONG.
02 tmFirstChar pic x(64).
02 tmLastChar pic x(64).
02 tmDefaultChar pic x(64).
02 tmBreakChar pic x(64).
02 tmItalic WORD.
02 tmUnderlined WORD.
02 tmStruckOut WORD.
02 tmPitchAndFamily WORD.
02 tmCharSet WORD.

01 hSystemFont pic s9(9) comp-5 value 0.
01 hNewFont pic s9(9) comp-5 value 0.
01 hWindowFont pic s9(9) comp-5 value 0.
01 MyCounter pic 9(9) comp-5 value 0.
01 MyMirrorImage pic x(16) value low-values.

Local-Storage Section.
01 MyMirrorImage1 TEXTMETRIC.

Linkage Section.
01 MyMirrorImage2 TEXTMETRIC.

Procedure Division.
0001-main.
move hSystemFont to hWindowFont
move MyMirrorImage1 to MyMirrorImage
call "MyArrayImage" using MyMirrorImage1

if tmHeight (MyMirrorImage1) not equal
tmHeight (MyMirrorImage2)
call winapi "SelectObject" using
by value hDC
by value hNewFont
end-call
end-if
stop run

entry "MyArrayImage" using MyMirrorImage2
call winapi "SelectObject" using
by value hDC
by value hWindowFont
end-call
call winapi "GetTextMetrics" using
by value hDC
by reference MyMirrorImage
end-call
perform until MyCounter = 1
move hNewFont to hWindowFont
move MyMirrorImage2 to MyMirrorImage
add 1 to MyCounter
call "MyArrayImage" using MyMirrorImage2
end-perform
exit program

end program Mirror.

Richard

2005-04-24, 8:55 pm

> I want the runtime system to automatically create that storage block
> for each array,

> 01 MyMirrorImage pic x(16) value low-values.
> Local-Storage Section.
> 01 MyMirrorImage1 TEXTMETRIC.
> Linkage Section.
> 01 MyMirrorImage2 TEXTMETRIC.

Well it's not actually doing that. The Linkage section area is just
mapped over MyMirrorImage so that is one that you created, and there
will always be a LOCAL-STORAGE one while the program is active, in fact
there will be up to 3, but you only use one.

So you have, through L-S caused one to be created, but that happens
without all the complexification of a non-standard ENTRY, and
recursion. It is just complexity for complexity's sake.

> So, MyMirrorImage1 would have its own storage block for a single copy
of an
> array, which I can use it as subscript or a pointer, to uniquely
identify an
> array of fonts.

It would be helpful if you learnt and used the correct terminology.

> I must capture the returned data for all the members of the array,

It is NOT 'an array', it is a record. A block of different fields is a
record. An array is where there are several records that are the same,
usually done with OCCURS nn.

> can use it as subscript or a pointer,

A subscript is a number that has a value between 1 and nn where nn is
the value in the OCCURS. It is of the form field(nn).

A pointer is a memory address it must be dereferenced to use it, you
cannot use a pointer as a subscript.

> Yes, tmHeight of MyMirrorImageX.

That is using a _qualifier_.

Your use of recursion does nothing that isn't done by simply using a
L-S and performing a paragraph twice that does the Windows CALLs.

Kellie Fitton

2005-04-24, 8:55 pm

Hi Richard,

Lets start from the top, again. :--))

Richard wrote:
> Well it's not actually doing that. The Linkage section area is just
> mapped over MyMirrorImage so that is one that you created, and there
> will always be a LOCAL-STORAGE one while the program is active, in
fact
> there will be up to 3, but you only use one.

if I use the local storage and perform a paragraph twice and get two
mirrorImages of the same structure, then:
how do I reference each member of each structure? for instance, how to
differentiate between members of both structures, when they have the
same names (i.e. tmHeight(array 1) and tmHeight(array 2))??

> It would be helpful if you learnt and used the correct terminology.

which terminology you did not like or incorrect, storage block? or
single copy?

> It is NOT 'an array', it is a record. A block of different fields is
a
> record. An array is where there are several records that are the
same,
> usually done with OCCURS nn.

my understanding of a record definition is: a collection of multiple
fields or columns that pertains to a single entity to form a record
in a FILE --- an array or structure is the table that I am passing as
an argument using the "by reference clause" within the win32 API call,
or collecting information into from the win32 API call. Right?

Regards, Kellie.

James J. Gavan

2005-04-24, 8:55 pm

Kellie Fitton wrote:
> Hi Richard,
>
> Lets start from the top, again. :--))
>
> Richard wrote:
>
>
> fact
>
>
>
> if I use the local storage and perform a paragraph twice and get two
> mirrorImages of the same structure, then:
> how do I reference each member of each structure? for instance, how to
> differentiate between members of both structures, when they have the
> same names (i.e. tmHeight(array 1) and tmHeight(array 2))??
>
>
You haven't got the exact coding but you ARE SOooo close. I think one of
the things you were wanting to do on this was COMPARE tmHeight for
equality ?

move 1 to index1
move 2 to index2

if tmheight(Index1) = ( or <> ) tmHeight (Index2)
then do this

Another way, assuming you were wanting to set the index as a temporary
CONSTANT for a series of operations :-

move 15 to MyIndex *> Don't move 15 if you only have 2 :-)

if tmHeight(MyIndex) > xxxx or < yyyy
then do something else

PS: Private e-mail - any luck with latest Treeview ?

Jimmy

>
>
>
> which terminology you did not like or incorrect, storage block? or
> single copy?
>
>
>
>
> a
>
>
> same,
>
>
>
>
> my understanding of a record definition is: a collection of multiple
> fields or columns that pertains to a single entity to form a record
> in a FILE --- an array or structure is the table that I am passing as
> an argument using the "by reference clause" within the win32 API call,
> or collecting information into from the win32 API call. Right?
>
> Regards, Kellie.
>

Richard

2005-04-24, 8:55 pm

> if I use the local storage and perform a paragraph twice and get two
> mirrorImages of the same structure, then:
> how do I reference each member of each structure?

You don't, which is why what you are doing is not necessarily a useful
way of going about the problem. Each iteration has its own private L-S
therefore you will have 3 created only one of which is actually useful.

> my understanding of a record definition is: a collection of multiple
> fields or columns that pertains to a single entity to form a record
> in a FILE --

It doesn't have to be in a file to be a record. In Cobol a 'record' is
any 01 level with subsiduary items. If it is in File Section then it
will describe a file record.

> an array or structure is the table that I am passing as an argument

An array or table has a number of consequtive occurances of a group or
elementary items and is created using the OCCURS clause.

You are not passing an 'array', you are passing a record (01 level).

James J. Gavan

2005-04-27, 3:55 am

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