World of Shareware - Software Farm 2/wosw_2.zip/wosw_2/DATABASE/SCR2FRG.ZIP/SCR2FRG.DOC

Text File | 1990-05-14 | 12KB | 260 lines

   This article is reprinted from the March 1990 edition of
TechNotes/dBASE IV  Due to the limitations of this media, certain
graphic elements such as screen shots, illustrations and some tables
have been omitted.  Where possible, reference to such items has been
deleted.  As a result, continuity may be compromised.

TechNotes is a monthly publication from the Ashton-Tate Software
Support Center.  For subscription information, call 213-538-6060.


====================================================================


What Were Once Screens
Are Now Reports
---------------
Copy of the March 1990 issue Ashton-Tate's Technotes magazine

By BRYAN FLYNN

Editors Note:

Since this article discusses the use of .GEN files and Template
Language, you will need  the Template Language compiler and
documentation which is included only with the  Developer's
Edition of dBASE IV.  For those with the standard edition, you
may take  advantage of this new .GEN file, Scr2Frg.GEN, which
creates reports from existing screen forms  without the need for
programming, by accessing the Ashton-Tate Bulletin Board,
CompuServe, or GEnie.

One of the strengths of dBASE IV is the
What-You-See-Is-What-You-Get (WYSIWYG)  approach of creating
Reports (.FRM files) and Screen Forms (.SCR files).  Many times,
a report  that duplicates a screen form is needed.  For instance,
a hard copy of a data entry record is a  typical example.

There are three ways to create a report from a screen form.  One
way is to create a report  that looks exactly like your screen
form.  However, if your screen form is fairly complex, this
could be a redundant, time consuming affair.  Another way is to
incorporate a copy of the .FMT  code created when you saved your
screen form into a program.  This requires programming  knowledge
which could find you spending more time converting and less time
producing results.

You might ponder, "Wouldn't it be nice if dBASE IV did this for
me  automatically?"   Since the layout is already there, why
can't dBASE IV do it?  Well, good news!  It can!  That's  the
third and most desirable solution and the point of this article.

The easy solution to the above problem is to have a dBASE IV
template do the work for  us.  The template source code presented
at the end of this article will take an existing screen  form
(.SCR) and generate a report form file (.FRG).   This report file
can then be used in  conjunction with the REPORT FORM command or
run from the Control Center.

A Brief Explanation of the Template Language

The Template Language takes dBASE IV design files (in our case
the .SCR file) and  generates either documentation or program
versions of these objects via the Template Language  Compiler.
Other design sources include .FRM, .LBL, .BCH, .APP, .POP and
.BAR files.

Consider each design file as a stack of items.  For example, a
screen form can contain a  stack of items consisting of fields,
boxes, text, memory variables, and calculated fields.  Each of
these items have certain attributes such as row and column
position, display length, data type,  and other specific
attributes.  Attribute descriptions of these items are kept in
definition files  (.DEF files).  The definition file for screen
forms is called FORM.DEF.

The Template Language enables you to retrieve items from these
design files, examine  them, and generate code depending upon the
items examined.  When you create a screen form,  dBASE IV
retrieves the stack of items contained in the .SCR file, passes
it through FORM.GEN  and generates a .FMT file (called a format
file).

The Template Language contains tools, consisting of control
structures, file handling  capabilities, and functions to scan
through a design file and determine what is outputted.   These
tools are used to create Template Language programs.  The source
code for Template  Language programs are kept in .COD files.
These .COD files are then compiled into .GEN files.   Using
Template Language, you can create your own custom made .GEN files
and control the  dBASE IV code outputted when generating labels,
reports, APGEN Applications, and Screen  Forms.

There are a number of existing .COD files in your DTL directory
that can be used freely as  examples or building blocks for your
own .COD files.  If you haven't installed them, check the
contents of your Template Language disks.

There are two basic steps to creating a .GEN file:

1.      Write the source code (.COD file) for the .GEN file using
        a text editor
2.      Compile the .COD file into a .GEN file using the DTC.EXE
        program. dBASE IV uses these default template names to
        create the related code and object files for the
        following:

*Labels:   LABEL.GEN
*Reports:  REPORT.GEN
* AppsGen:  MENU.GEN
*Screens:  FORM.GEN

The .COD files that generated these files are called LABEL.COD,
REPORT.COD,  AS_MENU.COD and FORM.COD respectively.

Please note that any existing  report file with the same name as
your screen form will be  overwritten.  If you have an existing
report with the same name as your screen, it is important  to
first copy your .SCR file to a new name so that it will not
conflict with the similarly named  report.

A more complete explanation of the Template Language can be found
in the Developer's  Edition manual entitled Using the Template
Language.

How to use Scr2Frg.GEN

Begin by either typing in the listed template code at the end of
this article or retrieving it  from the Ashton-Tate Electronic
Bulletin Board.  Compile it by entering at the DOS prompt:

DTC -iScr2Frg.COD

DTC.EXE is the Template Compiler which comes with the dBASE IV
Developer's  Edition.

The "-i" parameter prefaces the file being submitted to the
compiler, indicating it as the  input file.  Once Scr2Frg.COD is
successfully compiled, a file named Scr2Frg.GEN will exist.
Copy the .GEN file (Scr2Frg.GEN) into your dBASE IV directory, if
it doesn't already reside  there.

You're now ready to generate a new .FRG file from an existing
screen form. At the DOS prompt enter:

SET DTL_FORM=Scr2Frg.GEN

This specifies dBASE IV to use the Scr2Frg.GEN file instead of
the default FORM.GEN.  Now  go into dBASE IV and modify the
screen form from which you want to create a report.  Once  you're
in the layout screen, press Ctrl-End.  This will force
regeneration of your design screen and  create a new .FRG file by
the same name as that screen.

It is important that the SET DTL command, which sets a DOS
environmental variable, not  be executed while in a DOS access of
a dBASE IV session.  A DOS access is a copy of the  environment
and not a return to the original DOS environment which exists
before and after a  dBASE IV session.  Therefore, any SET command
would be eliminated upon the return to dBASE  IV via the DOS
access.

Points to consider

If the screen you're regenerating does not have an existing .FMT
file, the error message  "File could not be found" will appear.
The error appears because dBASE IV tries to compile a  .FMT file
any time you save a screen.  If one doesn't exist, the above
error message appears  which may be ignored.

After generation, you can then run the .FRG file from either the
Control Center or the dot  prompt as if it were a regular
report.  If you want to place the new report in the Control
Center,  you must first run the report initially from the dot
prompt.  The reason for this is that the  Control Center will
only let you add .FRM or .FRO (the interface and object) files
and the  Scr2Frg.GEN template file creates only a .FRG (program
code) file.  Running the report with  the REPORT FORM command
will automatically create a .FMO file.

One point that may not be obvious to newer users is that no
design file (.FRM)  is created.   The report you create using the
Scr2Frg.GEN file cannot be modified via MODIFY REPORT  since the
initial design data was from the screen form.

Scr2Frg.COD Usage Notes
*       Scr2Frg will create a report that looks exactly like your
        screen (except for the status bar).   This also includes
        memos in windows looking exactly the same.
*       After each record, a page eject will occur.
*       A screen will always take up a minimum of either 25 or 43
        lines depending upon what  display mode dBASE IV was in
        when the screen report was generated.  Consequently, even
        a  screen with one line of information will generate 25
        to 43 lines when printed.
*        If you would like to print more than one screen per
        page, you'll need to adjust the system  memory variables
        _plength and _padvance.  _plength specifies your page
        length and  _padvance specifies whether to advance the
        paper with either line feeds or a form feed.

        Example: Your screen is 25 lines in length and your
        physical page length is 66 lines.  To place  two screens
        per page, set  plength to 33 and _padvance to "Linefeeds"
        (instead of the default  "Formfeed").  This will place
        one screen for each 33 lines.

        These two variables can either be set from the dot
        prompt, in a program, or from the Print  menu.  When
        setting these from the Print menu, page length would be
        set under the Print:  Page dimensions menu.  The method
        of advancing a page (formfeed vs. linefeeds)  would be
        set from the Print: Control of printer menu.
*       The line number on which item numbers are placed when
        creating a screen is respected.  This  means that an item
        on the 26th line of a two screen screen form will print
        on the 26th line of  the report and not on a separate
        page.
*       A heading can be specified with the REPORT FORM command,
        using the HEADING  parameter, and will appear at the top
        of each page.  The number of lines in the heading will
        be added on to the screen size.  Suppose you have a three
        line header and you're printing a 25  line screen.  The
        total number of lines needed to print each record would
        then be 28.
*       The PLAIN and SUMMARY options of the REPORT FORM command
        are ignored except  where PLAIN is included with the
        HEADING option.  These two options are mutually
        exclusive with the PLAIN option taking precedence.
*       An optional page break will be inserted on whatever line
        desired if that line has  .PB in the  first column.  This
        feature could be helpful if, for instance, you have a
        four page screen form  and you'd like everything after a
        certain line to appear on a new page.  To use, simply
        type  .PB in the first column on the line you want to
        begin the next page.  The next time you  regenerate your
        screen with the Scr2Frg.GEN template active, a report
        will be generated  with a page break at that point.  Do
        not specify a page break while a  box is printing as
        defined boxes will not respect a page break.
*       When finished generating reports from screen forms by
        using Scr2Frg.GEN, make sure to set  your form template
        back to its default.  This is done by entering at the DOS
        prompt:

    SET DTL_FORM=

Since nothing is specified after the equal sign, DTL_FORM is
erased from memory and the  default FORM.GEN will now be assumed.

The Scr2Frg.GEN file is just one example of how a feature can be
added to the  product simply by using the appropriate template
and represents a very useful  flexibility of dBASE IV.  Remember
that custom made templates can be as simple  or complex as you
wish and while it might take some time to write a template,  the
time saved in developing a system or the added flexibility to a
system could  more than compensate.