Object Oriented Programming with APL+Win

It is possible to do real Object Oriented Programming with APL+Win!

And believe it or not, this can be extremely simple and clear. So simple that, if you learn it and taste it there is a high chance you'll become addicted!

This 115 pages lesson teaches all the basic concepts of Object Oriented Programming, shows you how to implement them in APL+Win through numerous very simple examples, and gives you the one self-contained Qwi utility which allows you to use pure OOP in APL+Win.

You will be learning:

• what objects are
• how to create your own new classes of objects
• how to build a hierarchy of classes
• how to fully use inheritance
• how to overload methods and properties
• what is a superclass
• how to override methods and properties by calling superclass methods and properties
• what polymorphism is and how to use it
• how to use encapsulation

Not only developing your own new classes of objects is very simple once you have read this lesson, but you then use them with the Qwi utility which shares the same syntax as the APL+Win ŒWI user interface system function. See an example below.

With this lesson, you will immediately be able to start defining your own new classes of objects and benefit from the many advantages of real Object Oriented Programming in APL+Win:

• write truly reusable code
• avoid code duplication and rewrites with inheritance
• simplify programming with polymorphism
• greatly increase code sharing with other developers
• improve the consistency of your interface
• increase your software reliability
• increase your productivity

In this APL+Win Training we will be developing a good number of new very porwerful new classes of objects for APL+Win, starting with the first of them called: OCXPrinter

The first part of this Chapter describes how to use the brand new APL+Win OCX interface, using the Formula One OCX v4.1.5 spreadsheet. After reading these few pages you should be able to use any new OCX with APL+Win.
Then, in order to put the new Object Oriented technlogy into action, we build together a new class of object called OCXPrinter.

OCXPrinter is a rewrite of the GuiPrint utility presented in Chapter 11 (see Pack 3) this time implemented as an object and as a stand-alone APL function.

This object not only allows you to create and print almost any report you can imagine from APL+Win, with Excel quality, but also encapsulates new methods for directly importing and exporting data between APL and Excel 5/95, for example automatically installing planes of a 3-dim APL nested array in successive sheets of the Excel workbook.

OCXPrinter comes with 2 properties (ontop and visible) and more than 60 built-in methods (Add AddAcross AddColPageBreak AddPageBreak AddRowPageBreak Align Auto AutoAll BackColor BlankZeroes Bold Border BottomMargin Clear ClearAll Close ColWidth Copy DefaultFont Export FitToPage Font FontColor FontName FontSize Footer FooterFont FooterMargin Format Get GetSelRef GridHeadings GridLines HCenter HLine Header HeaderFont HeaderMargin Import Italic LeftMargin Margins Move New NextRowPageBreak Open Orient Preview Print PrintArea PrintGridLines PrintHCenter PrintScale PrintTitles PrintVCenter RemoveColPageBreak RemovePageBreak RemoveRowPageBreak Resize RightMargin Scale Sel SelAll SelRef TopMargin Underline VCenter VLine).

Here is an example using the OCXPrinter object. To print the following report:

you need to write the following straight forward APL function:

    ’ OCXPrinterTest;L;S;data;pos;Œwself
[1]   ©’ OCXPrinterTest -- Sample report using the OCXPrinter object
[2]
[3]   L„ListSeparator   © retrieve Windows Intl list separator setting
[4]
[5]   data„((›''),months,¨' '),(days,¨›'  ')®¯2000+?12 7½10000
[6]
[7]   © Create instance of OCXPrinter object
[8]   Œwself„'ff' Qwi 'New' 'OCXPrinter'('ontop' 1)('where' 2 10 31 107)
[9]
[10]  © Fill the grid with data
[11]  pos„ Qwi 'Add' (4 1) data
[12]
[13]  © Apply formating and add column headers
[14]       Qwi'Format' '[>0] [BLACK] # ###.00 ;[<0] [RED] (# ###.00);'
[15]       Qwi'Font' 'Impact' 14
[16]  pos„ Qwi'AddAcross' 3 (2 4) 'First 3 days'
[17]  pos„ Qwi'AddAcross' 3 (5 6) 'Last 2 days'
[18]  pos„ Qwi'AddAcross' 3 (7 8) 'Weekend'
[19]       Qwi('Sel' 'B3:H3')('BackColor' 192 192 192)('Font' 'Impact' 18)
[20]       Qwi('Sel'('B4:H4',L,'A3:A16'))('BackColor' 192 192 192)
[21]       Qwi('Align' 'right' 'center')'AutoAll'
[22]       Qwi('ColWidth'(¼9)(9½3800))('Sel' 1 1 1 1)
[23]
[24]  © Printer settings
[25]       Qwi('TopMargin' 1.6)('BottomMargin' 2) ©1.4
[26]       Qwi('HeaderMargin' .5)('FooterMargin' .5)
[27]       Qwi'HeaderFont' 'Arial' 12 'Arial Bold' 24 'Arial' 12
[28]       Qwi'FooterFont' 'Arial' 12 'Arial' 12 'Arial' 12
[29]           S„›'Uniware' 'APL Department' 'Year Report'
[30]           S„S,›'' 'APL Sales' '(1996)'
[31]           S„S,›'&D' '&T'
[32]       Qwi'Header' S
[33]           S„›'Copyright © 1997 Eric Lescasse'
[34]           S„S,›''
[35]           S„S,›'Page &P/&N'
[36]       Qwi'Footer' S
[37]       Qwi'Orient' 'landscape'
[38]       Qwi'PrintHCenter' 1
[39]
[40]  © Finish
[41]       Qwi'Preview'            © print preview
[42]  ©or: Qwi'visible' 1          © display Formula One form
[43]  ©or: Qwi'Print' 0            © print immediately (with no interface)
[44]  ©or: Qwi'Print' 1            © print dialog box
’

      apl3d„'This' 'is' 'a' '3D' 'nested' 'APL' 'array'
apl3d„apl3d,'containing' 'numbers' 'and' 'text',¼10
apl3d„4 6 7½apl3d

'ff' Qwi 'New' 'OCXPrinter' ('Export' 'c:\temp\temp.xls' apl3d)

      imported„'ff' Qwi 'Import' 'c:\temp\temp.xls'
½imported
4
	

      1œimported
       This      is   a   3D nested APL array
containing numbers and text      1   2     3
		4       5   6    7      8   9    10
 This      is   a   3D nested APL array
containing numbers and text      1   2     3
		4       5   6    7      8   9    10

      ½¨imported
6 7  6 7  6 7  6 7

      ½œimported
4 6 7

From the above Import/Export example which demonstrates invoking methods of a new class of APL+Win objects (OCXPrinter) you can see how easy it is to use an object. And the good news are that, with this lesson, you will learn how to easily customize an object like OCXPrinter by adding your own methods and properties. You will also be able to create child classes of the OCXPrinter class and fully use inheritance and polymorphism to you greatest benefit.

This Pack WinWord document also talks about Resize handlers and how to automatically resize all children of a form when the form is resized.

2 utilities are provided: ResizeHandler and ResizeFontHandler which resizes all the fonts used in the form accordingly to the nesw form size.

Learn the techniques involved and reuse these 2 utilities as wished.

Here is an example:

The Tip of the Month

Pack 6 Content