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1989-07-27
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584 lines
_STRUCTURED PROGRAMMING COLUMN_
by Jeff Duntemann
[LISTING ONE]
{--------------------------------------------------------------}
{ PrinByte }
{ }
{ Byte-value print object for object extendability demo }
{ }
{ by Jeff Duntemann }
{ Turbo Pascal V5.5 }
{ Last modified 5/11/89 }
{--------------------------------------------------------------}
UNIT PrinByte;
INTERFACE
USES Printer;
{--------------------------------------------------------------}
{ The PrintByte object "knows" how to print its byte value in }
{ four different formats: As decimal quantity, hex quantity, }
{ binary quantity, and extended ASCII symbol. It takes the }
{ cautious path in printing symbols, as prints spaces for all }
{ of the "control" characters 0-31, "rubout" ($7F), and char }
{ $FF. If your printer has some means of printing smiley }
{ faces and all that other folderol in the low 32 characters, }
{ override the PrintSymbol method with a new method that uses }
{ whatever mechanism your printers offers to print those }
{ characters "spaced out" by this implementation of the }
{ PrintSymbol method. }
{--------------------------------------------------------------}
TYPE
PrintByte = OBJECT
BV : Byte; { Byte value }
FUNCTION DontPrint(ShouldI : Byte) : Boolean;
PROCEDURE PrintDecimal;
PROCEDURE PrintHex;
PROCEDURE PrintBinary;
PROCEDURE PrintSymbol;
END;
IMPLEMENTATION
{ Returns True for any code that CANNOT be printed verbatim }
FUNCTION PrintByte.DontPrint(ShouldI : Byte) : Boolean;
CONST
NotThese = [0..31,127,255]; { Unprintable codes }
BEGIN
IF ShouldI IN NotThese THEN DontPrint := True
ELSE DontPrint := False;
END;
PROCEDURE PrintByte.PrintDecimal;
BEGIN
Write(LST,BV:3);
END;
PROCEDURE PrintByte.PrintHex;
CONST
HexDigits : ARRAY[0..15] OF Char = '0123456789ABCDEF';
BEGIN
Write(LST,HexDigits[BV SHR 4],HexDigits[BV AND $0F]);
END;
PROCEDURE PrintByte.PrintBinary;
VAR
Index : Integer;
BEGIN
FOR Index := 7 DOWNTO 0 DO
IF Odd(BV SHR Index) THEN Write(LST,'1')
ELSE Write(LST,'0');
END;
PROCEDURE PrintByte.PrintSymbol;
BEGIN
IF DontPrint(BV) THEN
Write(LST,' ')
ELSE
Write(LST,Chr(BV));
END;
END.
[LISTING TWO]
{--------------------------------------------------------------}
{ ASCIIChart }
{ }
{ Object Extendability demo program: Prints an ASCII chart }
{ }
{ Note: This program contains control codes specific to }
{ the HP Laserjet Series II Printer. Use with }
{ other printers may be hazardous to your aesthetic }
{ sensibilities. }
{ }
{ Jeff Duntemann }
{ Turbo Pascal V5.5 }
{ Last modified 6/8/89 }
{--------------------------------------------------------------}
{--------------------------------------------------------------}
{ Run this on an HP Laserjet Series II, and you'll get an }
{ ASCII chart including all the weird characters for which the }
{ Series II has characters in its built-in fonts. If you have }
{ some other printer, you need only modify the PrintSymbol }
{ method to use whatever mechanism your printer has to print }
{ the weird characters. By modifying PrintSymbol you are }
{ extending the object PrintByte defined in unit PRINBYTE.PAS, }
{ WITHOUT needing full source code to PRINBYTE.PAS. }
{--------------------------------------------------------------}
PROGRAM ASCIIChart;
USES Printer, { Standard Borland unit }
PrinByte; { PRINBYTE.PAS from DDJ for September 1989 }
CONST
Title = 'THE EXTENDED ASCII CODE AND SYMBOL SET';
Header = ' Dec Hex Binary Symbol Dec Hex Binary Symbol';
BarChar = Chr(205);
ColChar = Chr(177);
FormFeed = Chr(12);
TYPE
{---------------------------------------------------------------}
{ This is a child object of PrintByte, defined in separate file }
{ PRINBYTE.PAS. Remember: PrintByteHP inherits EVERYTHING }
{ defined in PrintByte. EVERYTHING! The only difference is }
{ that the PrintSymbol method is overridden by an HP Series II }
{ specific symbol-print method. Everything else is EXACTLY as }
{ it is defined in PrintByte. }
{---------------------------------------------------------------}
PrintByteHP = OBJECT(PrintByte)
PROCEDURE PrintSymbol
END;
VAR
I,J,K : Integer;
Char1,Char2 : PrintByteHP; { Instances of PrintByteHP object type }
{--------------------------------------------------------------}
{ This method overrides the PrintSymbol method defined in the }
{ PrintByte parent object defined in PRINCHAR.PAS: }
{--------------------------------------------------------------}
PROCEDURE PrintByteHP.PrintSymbol;
BEGIN
IF DontPrint(BV) THEN { If DontPrint method says so, }
Write(LST,Chr(27),'&p1X',Chr(BV)) { use "transparent data print" }
ELSE { feature to print weird chars }
Write(LST,Chr(BV)); { Otherwise, just print 'em... }
END;
PROCEDURE Spaces(NumberOfSpaces : Integer);
VAR
Index : Integer;
BEGIN
FOR Index := 1 TO NumberOfSpaces DO
Write(LST,' ')
END;
PROCEDURE NewPage;
VAR
Index : Integer;
BEGIN
Write(LST,FormFeed);
END;
PROCEDURE PrintHeader;
VAR
Index : Integer;
BEGIN
Spaces(10);
Writeln(LST,Header);
Spaces(10);
FOR Index := 1 TO 60 DO
Write(LST,BarChar);
Writeln(LST);
END;
{--------------------------------------------------------------}
{ Nothing more elaborate here than printing the byte out as a }
{ decimal number, a hex number, a binary number, and a symbol. }
{ The four "Target." calls are method calls to the object }
{ passed to PrintChar in the Target parameter. }
{--------------------------------------------------------------}
PROCEDURE PrintChar(Target : PrintByteHP);
BEGIN
Spaces(3);
Target.PrintDecimal;
Spaces(3);
Target.PrintHex;
Spaces(3);
Target.PrintBinary;
Spaces(3);
Target.PrintSymbol;
Spaces(4);
END;
{--------------------------------------------------------------}
{ This simply sets the HP Series II to its PC symbol set. }
{--------------------------------------------------------------}
PROCEDURE InitHP;
BEGIN
Write(LST,Chr(27),'(10U'); { Select symbol set 10U }
END;
BEGIN
InitHP; { Select the PC symbol set }
Spaces(10); { Output 10 spaces }
Writeln(LST,Title); { Print out the title string }
Writeln(LST); { Space down one line }
FOR I := 0 TO 3 DO { 256 characters takes 4 pages }
BEGIN
FOR K := 1 TO 3 DO Writeln(LST); { Space down 3 lines }
PrintHeader; { Print the chart header }
FOR J := 0 TO 31 DO { Do 2 columns of 32 chars. }
BEGIN
Char1.BV := (I*64)+J; Char2.BV := (I*64)+J+32;
Spaces(10);
PrintChar(Char1); { Print the left column character }
Write(LST,ColChar); { Print the column separator }
PrintChar(Char2); { Print the right column character }
Writeln(LST);
END;
NewPage; { Issue a form feed to printer }
END;
END.
[LISTING THREE]
{--------------------------------------------------------------}
{ PrinByte }
{ }
{ Byte-value print object for object extendibility demo }
{ }
{ by Jeff Duntemann }
{ QuickPascal V1.0 }
{ Last modified 6/6/89 }
{--------------------------------------------------------------}
UNIT PrinByte;
INTERFACE
USES Printer;
{--------------------------------------------------------------}
{ The PrintByte object "knows" how to print its byte value in }
{ four different formats: As decimal quantity, hex quantity, }
{ binary quantity, and extended ASCII symbol. It takes the }
{ cautious path in printing symbols, as prints spaces for all }
{ of the "control" characters 0-31, "rubout" ($7F), and char }
{ $FF. If your printer has some means of printing smiley }
{ faces and all that other folderol in the low 32 characters, }
{ override the PrintSymbol method with a new method that uses }
{ whatever mechanism your printers offers to print those }
{ characters "spaced out" by this implementation of the }
{ PrintSymbol method. }
{--------------------------------------------------------------}
TYPE
PrintByte = OBJECT
BV : Byte; { Byte value }
FUNCTION DontPrint(ShouldI : Byte) : Boolean;
PROCEDURE PrintDecimal;
PROCEDURE PrintHex;
PROCEDURE PrintBinary;
PROCEDURE PrintSymbol;
END;
IMPLEMENTATION
{ Returns True for any code that CANNOT be printed verbatim }
FUNCTION PrintByte.DontPrint(ShouldI : Byte) : Boolean;
CONST
NotThese = [0..31,127,255]; { Unprintable codes }
BEGIN
IF ShouldI IN NotThese THEN DontPrint := True
ELSE DontPrint := False;
END;
PROCEDURE PrintByte.PrintDecimal;
BEGIN
Write(LST,Self.BV:3);
END;
PROCEDURE PrintByte.PrintHex;
CONST
HexDigits : ARRAY[0..15] OF Char = '0123456789ABCDEF';
BEGIN
WITH Self DO
Write(LST,HexDigits[BV SHR 4],HexDigits[BV AND $0F]);
END;
PROCEDURE PrintByte.PrintBinary;
VAR
Index : Integer;
BEGIN
WITH Self DO
FOR Index := 7 DOWNTO 0 DO
IF Odd(BV SHR Index) THEN Write(LST,'1')
ELSE Write(LST,'0');
END;
PROCEDURE PrintByte.PrintSymbol;
BEGIN
WITH Self DO
IF DontPrint(BV) THEN
Write(LST,' ')
ELSE
Write(LST,Chr(BV));
END;
END.
[LISTING FOUR]
{--------------------------------------------------------------}
{ ASCIIChart }
{ }
{ Object Extendability demo program: Prints an ASCII chart }
{ }
{ Note: This program contains control codes specific to }
{ the HP Laserjet Series II Printer. Use with }
{ other printers may be hazardous to your aesthetic }
{ sensibilities. }
{ }
{ Jeff Duntemann }
{ QuickPascal V1.0 }
{ Last modified 6/6/89 }
{--------------------------------------------------------------}
{--------------------------------------------------------------}
{ Run this on an HP Laserjet Series II, and you'll get an }
{ ASCII chart including all the weird characters for which the }
{ Series II has characters in its built-in fonts. If you have }
{ some other printer, you need only modify the PrintSymbol }
{ method to use whatever mechanism your printer has to print }
{ the weird characters. By modifying PrintSymbol you are }
{ extending the object PrintByte defined in unit PRINBYTE.PAS, }
{ WITHOUT needing full source code to PRINBYTE.PAS. }
{--------------------------------------------------------------}
PROGRAM ASCIIChart;
USES Printer, { Standard Borland unit }
PrinByte; { PRINBYTE.PAS from DDJ for September 1989 }
CONST
Title = 'THE EXTENDED ASCII CODE AND SYMBOL SET';
Header = ' Dec Hex Binary Symbol Dec Hex Binary Symbol';
BarChar = Chr(205);
ColChar = Chr(177);
FormFeed = Chr(12);
TYPE
{---------------------------------------------------------------}
{ This is a child object of PrintByte, defined in separate file }
{ PRINBYTE.PAS. Remember: PrintByteHP inherits EVERYTHING }
{ defined in PrintByte. EVERYTHING! The only difference is }
{ that the PrintSymbol method is overridden by an HP Series II }
{ specific symbol-print method. Everything else is EXACTLY as }
{ it is defined in PrintByte. }
{---------------------------------------------------------------}
PrintByteHP = OBJECT(PrintByte)
PROCEDURE PrintSymbol; OVERRIDE
END;
VAR
I,J,K : Integer;
Char1,Char2 : PrintByteHP; { Instances of PrintByteHP object type }
{--------------------------------------------------------------}
{ This method overrides the PrintSymbol method defined in the }
{ PrintByte parent object defined in PRINCHAR.PAS: }
{--------------------------------------------------------------}
PROCEDURE PrintByteHP.PrintSymbol;
BEGIN
WITH Self DO
IF Self.DontPrint(BV) THEN { If DontPrint method says so, }
Write(LST,Chr(27),'&p1X',Chr(BV)) { use "transparent data print" }
ELSE { feature to print weird chars }
Write(LST,Chr(BV)); { Otherwise, just print 'em... }
END;
PROCEDURE Spaces(NumberOfSpaces : Integer);
VAR
Index : Integer;
BEGIN
FOR Index := 1 TO NumberOfSpaces DO
Write(LST,' ')
END;
PROCEDURE NewPage;
VAR
Index : Integer;
BEGIN
Write(LST,FormFeed);
END;
PROCEDURE PrintHeader;
VAR
Index : Integer;
BEGIN
Spaces(10);
Writeln(LST,Header);
Spaces(10);
FOR Index := 1 TO 60 DO
Write(LST,BarChar);
Writeln(LST);
END;
{--------------------------------------------------------------}
{ Nothing more elaborate here than printing the byte out as a }
{ decimal number, a hex number, a binary number, and a symbol. }
{ The four "Target." calls are method calls to the object }
{ passed to PrintChar in the Target parameter. }
{--------------------------------------------------------------}
PROCEDURE PrintChar(Target : PrintByteHP);
BEGIN
Spaces(3);
Target.PrintDecimal;
Spaces(3);
Target.PrintHex;
Spaces(3);
Target.PrintBinary;
Spaces(3);
Target.PrintSymbol;
Spaces(4);
END;
{--------------------------------------------------------------}
{ This simply sets the HP Series II to its PC symbol set. }
{--------------------------------------------------------------}
PROCEDURE InitHP;
BEGIN
Write(LST,Chr(27),'(10U'); { Select symbol set 10U }
END;
BEGIN
InitHP; { Select the PC symbol set }
New(Char1); New(Char2); { Create objects on the heap }
Spaces(10); { Output 10 spaces }
Writeln(LST,Title); { Print out the title string }
Writeln(LST); { Space down one line }
FOR I := 0 TO 3 DO { 256 characters takes 4 pages }
BEGIN
FOR K := 1 TO 3 DO Writeln(LST); { Space down 3 lines }
PrintHeader; { Print the chart header }
FOR J := 0 TO 31 DO { Do 2 columns of 32 chars. }
BEGIN
Char1.BV := (I*64)+J; Char2.BV := (I*64)+J+32;
Spaces(10);
PrintChar(Char1); { Print the left column character }
Write(LST,ColChar); { Print the column separator }
PrintChar(Char2); { Print the right column character }
Writeln(LST);
END;
NewPage; { Issue a form feed to printer }
END;
END.
