Grigory Filatov

Contributed works of Grigory Filatov

Adaptation FiveWin TsBrowse class
Color Table
Center Window’s Title
Closes application when no activity
Copy Protection (Get BIOS Name)

GetFonts
Get list of all controls

GIF animation demo

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Andrés González López

Contributed works of Andrés González López

Anchor Windows (ON MOUSEDRAG)
Bos Taurus – Incredible !!! 
DEFINE REPORT (with filtered data)
Demo Debug
Generate PDF files
Improved interfaces (Label Button)
My color list (i_color.ch)

DISPLAY

DISPLAY

Display records to the console

Syntax

      DISPLAY <exp list>
             [TO PRINTER] [TO FILE <xcFile>]
             [<scope>] [WHILE <lCondition>]
             [FOR <lCondition>] [OFF]

Arguments

<exp list> is the list of values to display for each record processed.

TO PRINTER echoes output to the printer.

TO FILE <xcFile> echoes output to the indicated file which can be specified either as a literal file name or as a character expression enclosed in parentheses. If an extension is not specified, .txt is added.

<scope> is the portion of the current database file to DISPLAY. The default is the current record, or NEXT 1. If a condition is specified, the scope becomes ALL.

WHILE <lCondition> specifies the set of records meeting the condition from the current record until the condition fails.

FOR <lCondition> specifies the conditional set of records to DISPLAY within the given scope.

OFF suppresses the display of the record number.

Description

DISPLAY is a database command that sequentially accesses records in the current work area, sending the results of the <exp list> to the console in a tabular format with each column separated by a space. The command does not display column headers or pause at predetermined intervals. DISPLAY is identical to LIST with the exception that its default scope is NEXT 1 rather than ALL.

When invoked, output is sent to the screen and optionally to the printer and/or a file. To suppress output to the screen while printing or echoing output to a file, SET CONSOLE OFF before the DISPLAY command line.

Notes

. Interrupting output: To let the user interrupt the processing of a DISPLAY command, using the INKEY() function, add a test for the interrupt key press to the FOR condition. See the example below. . Printer margin: Since DISPLAY is a console command, it honors the current SET MARGIN for output echoed to the printer.

Examples

      .  This example illustrates a simple DISPLAY, and a conditional
      DISPLAY to the printer:
      USE Sales NEW
      DISPLAY DATE(), TIME(), Branch
      DISPLAY Branch, Salesman FOR Amount > 500 TO PRINTER
      .  This example interrupts a DISPLAY using INKEY() to test
      whether the user pressed the Esc key:
      #define K_ESC  27
      USE Sales INDEX SalesMan NEW
      DISPLAY Branch, Salesman, Amount WHILE ;
         INKEY() != K_ESC

Seealso

DBEVAL(), INKEY(), LIST, SET MARGIN

SP_MFIELDSTYPE

MFIELDSTYPE()

  Short:
  ------
  MFIELDSTYPE() Pops up a list of fields of given type(s)

  Returns:
  --------
  <cFieldName> => name of selected field

  Syntax:
  -------
  MFIELDSTYPE(cType,[cTitle],[nTop,nLeft,nBottom,nRight])

  Description:
  ------------
  <cType> is a string containing 1 or more field TYPE
  symbols:

       C   Character
       N   Numeric
       D   Date
       L   Logical
       M   Memo

  Only fields of this type(s) are presented for the
  picklist. If no fields of this type(s) are present, a "" is returned.

  [cTitle] is a string placed at the top of the popup
  box for a title

  [nTop,nLeft,nBottom,nRight] are the coordinates of
  the box

  Examples:
  ---------
   // this selects memo field to edit

   use customer

   cField := mfieldstype("M")

   if !empty(cField)
      memoedit(FIELDGET(FIELDPOS(cField)),0,0,24,79)
   endif

  Source:
  -------
  S_MFLDT.PRG

 

Coding Guidelines

Coding Guidelines

( by Greg Holmes )

Language Syntax 
The general rule of thumb is: built-in features in lowercase, and custom-written functions in mixed case. 
When specifying the complete syntax of a language element in documentation, the input items, parameters, and so on are referred to using the following symbols:

 Symbol  Description
< >  Indicates user input item
( )  Indicates function argument list
[ ]  Indicates optional item or list
{ }  Indicates code block or literal array
| |  Indicates code block argument list
–>  Indicates function return value
 Repeated elements if followed by a symbol
Intervening code if followed by a keyword
,  Item list separator
|  Indicates two or more mutually exclusive options
@  Indicates that an item must be passed by reference
*  Indicates a compatibility command or function

For example:

    len(<cString>|<aArray>) --> nLength

Metasymbols provide a place holder for syntax elements, and they describe the expected data types. A metasymbol consists of one or more lowercase data type designators followed by a mixed case description. This is known as Hungarian Notation.

 Designator  Description
a  Array
b  Code block
c  Character expression
d  Date expression
exp  Expression of any type
id  Literal identifier
l  Logical expression
m  Memo field
n  Numeric expression
o  Object
x  Extended expression

In this example, dnLower and dnUpper can be either date or numeric:

    @...get...range <dnLower>, <dnUpper>
Filenames and Aliases 
All filenames, in any context, are in upper case. Filenames follow DOS naming conventions (preferably limited to letters, numbers, and the underscore).

    use CUSTOMER
    nHandle := fopen('DATAFILE.DAT')

When referring to specific file types in documentation, include the period.
e.g. “A program is stored in a text file with a .PRG extension.” 
Alias names follow the same conventions as filenames, but are limited to A-Z, 0-9, and the underscore. If a filename begins with a number or contains unusual characters, an alias must be specified when the file is opened or an error will result. 
Note that CA-Clipper does not natively support Windows 95 long filenames, although third-party libraries are available to add the capability.

Fieldnames 
Fieldnames are all uppercase, and always include the alias of the table. Fieldnames may contain underscores, but should not begin with one (because the underscore is generally used to indicate an internal symbol).

    @ 10, 10 say BANKS->BRANCH
    nAge := CUSTOMER->CUST_AGE
Memory Variables 
Memory variables consist of a lowercase type designator followed by a mixed case description (see Hungarian Notation). Although CA-Clipper only recognizes the first 10 characters as unique, variable names may be longer.

    cString := "Hello World"
    nYearlyAverage := CalcYearAvg()

If you use Hungarian Notation for your memory variable names and include the table alias with fieldnames, there will be no conflict between the two.

Commands, Functions, and Keywords 
All built-in commands, functions, and keywords are lowercase. In documentation, the font should be Courier or a similar font. If fonts are not available, then bold or CAPITALIZE the word for emphasis. 
Never use abbreviations — this practice is not necessary with a compiler, although it was common in the early days of dBase (which was an interpreter). 
There should never be a space between the function name and the opening parenthesis. Also, note that the iif() function should never be spelled if().

    replace CUSTOMER->CUSTNAME with cCustName
    nKey := inkey(0)

When specifying commands that have clauses in documentation, separate the keywords with an ellipsis (...) and do not include the to clause, unless it is followed by the file,print, or screen keywords.

    copy...sdf
    set message...center
    @...say...get
Programmer-Defined Functions & Procedures 
These begin with an uppercase letter, followed by mixed case letters as appropriate.

    ? StripBlanks("Hello there, this will have no spaces.")

Function and procedure names may contain underscores, but should not begin with one (they may conflict with internal functions which often start with an underscore). There should be only one return statement per function or procedure, and it should not be indented.

    function SomeFunc (...)
      .
      . <statements>
      .
    return cResult

The return value of a function is not enclosed in parentheses, although parentheses may be used to clarify a complex expression.

    return nValue
    return (nCode * 47) + nAnswer
Preprocessor Directives 
Preprocessor directives are lowercase and are preceded by the # sign.

    #include 'INKEY.CH'

Optionally, you may use single quotes around header files that come with CA-Clipper and double quotes around your own. This convention is purely voluntary, but it helps to distinguish between the two. For example:

    #include 'INKEY.CH'
    #include "MY_APP.CH"

Manifest constants are uppercase.

    #define ESCAPE   27
    if lastkey() == ESCAPE

Pseudo-function names should also be uppercase.

    #define AREA(length, width)   ((length)*(width))
Declarations 
Local variables are grouped according to functionality, and may be declared on one or more lines. The declarations appear as the first code at the beginning of a function or procedure.

    procedure Main ( )
    local nTop, nLeft, nBottom, nRight
    local cOldScreen, cOldColor, nOldCursor

Variables may be declared one per line and accompanied by a description.

    local nCount        // Number of records found.
    local nTotal        // Sum of dollars.

The description can be omitted if better variable names are chosen.

    local nRecordCount
    local nDollarTotal

Variables can be initialized when they are declared, although it is often clearer (and safer) to initialize them immediately before they are used.

    local nRecordCount:=0
    local nDollarTotal:=0
Logicals 
The .T. and .F. are typed in uppercase.
Operators 
The in-line assignment operator (:=) is used for all assignments, and the exact comparison operator (==) is used for all comparisons.

    lContinue := .T.
    nOfficeTotal := nRegionTotal := 0
    lDuplicate := (CUSTFILE->CUSTNAME == cCustName)
    if nLineCount == 4  ...
    if left(PRODUCT->CODE, 3) == left(cProdCode, 3)  ...

Although the compound assignment operators (+=-=*=, etc.) are convenient, they should not be used if readability suffers.

    // The traditional way to accumulate:
    nTotal := nTotal + INVDETAIL->PRICE
    // A good use of a compound assignment operator:
    nTotal += INVDETAIL->PRICE
    // But what does this do?
    nVal **= 2

The increment (++) and decrement (--) operators are convenient, but can lead to obscure code because of the difference between prefix and postfix usage.

    nRecCount++
    nY := nX-- - --nX        // Huh?
Spacing 
Whenever a list of two or more items is separated by commas, the commas are followed by a space.

    MyFunc(nChoice, 10, 20, .T.)

Spaces may be used between successive parentheses.

    DoCalc( (nItem > nTotal), .F. )
    cNewStr := iif( empty(cStr), cNewStr, cStr + chr(13) )

Spaces should surround all operators for readability.

    nValue := 14 + 5 - (6 / 4)

In declarations, often spaces are not used around the assignment operator. This tends to make searching for the declaration of a variable easier.

    local lResult:=.F., nX:=0

Thus, searching for “nX :=” would find the lines where an assignment is made, while searching for “nX:=” would find the declaration line (such as the local above).

Indentation 
Indenting control structures is one of the easiest techniques, yet it improves the readability the most. 
Indent control structures and the code within functions and procedures 3 spaces.

    procedure SaySomething
       do while .T.
          if nTotal < 50
             ? "Less than 50."
          elseif nTotal > 50
             ? "Greater than 50."
          else
             ? "Equal to 50."
          endif
          ...
       enddo
    return

Case statements in a do…case structure are also indented 3 spaces.

    do case
       case nChoice == 1
          ? "Choice is 1"
       case ...
          ...
       otherwise
          ...
    endcase
Tabs 
Do not use tabs in source code — insert spaces instead. Tabs cause problems when printing or when moving from one editor to another, because of the lack of a standard tab width between editors and printers. Typically, printers expand tabs to 8 spaces which easily causes nested control structures to fall off the right-hand side of the page. Commonly, a source code editing program will insert the appropriate number of spaces when the <TAB> key is hit.
Line Continuation 
When a line of code approaches the 80th column, interrupt the code at an appropriate spot with a semicolon and continue on the next line. Indent the line so that it lines up in a readable manner.

    set filter to CUSTFILE->NAME  == 'John Smith  ';
            .and. CUSTFILE->STATE == 'OR'

To continue a character string, end the first line with a quote and a plus sign and place the remainder on the next line. Try to choose a logical place in the string to break it, either at a punctuation mark or after a space.

    @ 10, 10 say "The lazy brown fox tripped over " + ;
                 "the broken branch."
Quotes 
Use double quotes for text that needs to be translated (will appear on the screen), and single quotes for other strings.

    ? "Hello World!"
    cColor := 'W+/B'
    SelectArea('PROP')

This is a simple but extremely effective technique because translation departments often want to see the messages in context (in the source code), so the different quote types indicate which messages are to be translated and which should be left alone.

Comments 
Comments are structured just like English sentences, with a capital letter at the beginning and a period at the end.

    // Just like a sentence.
    /* This comment is longer. As you
       can see, it takes up two lines */

You may encounter old-style comment indicators if you maintain older (Summer’87 and earlier) code.

    && This is an older-style of comment indicator.
    *  The asterisk is also old.

For in-line comments, use the double slashes.

    use CUSTOMER            // Open the data file.
    goto bottom             // The last record.

Note that the ‘//‘ of in-line comments begins at column 40, if possible. This leaves enough room for a useful comment.

Source :  http://www.ghservices.com/gregh/clipper/guide.htm

Send to file

Write data to a file

Sending lines to a file is quite easy :

In addition of SET PRINTER on | OFF | <xlToggle> command, SET PRINTER, (like many other SET commands,) has a second form distinguished by TO keyword:

SET PRINTER TO [<xcDevice> | <xcFile> [ADDITIVE]]

The on|OFF form of SET PRINTER controls whether the output of console commands is echoed to the printer.

TO <xcDevice> identifies the name of the device where all subsequent printed output will be sent.

TO <xcFile> identifies the name of the output file. ( If a file extension is not specified, (.prn) is assumed.)

By using that last method we can send our lines to a file, instead of sending directly to printer:

 SET PRINTER TO Prnfile.txt
 SET DEVICE TO PRINTER
 SET PRINTER ON
 //
 @ 0, 0 SAY "This goes to Prnfile.txt"
 ? "So will this!"
 //
 SET DEVICE TO SCREEN
 SET PRINTER OFF
 SET PRINTER TO // Close the print file

Note that, though our target is not printer, we have use a SETting printer ON.

We have another method for sending someting to a file may be SET ALTERNATE command:

 SET ALTERNATE TO [<xcFile> [ADDITIVE]]
 SET ALTERNATE on | OFF | <xlToggle>

SET ALTERNATE is a console command that lets you write the output of console commands to a text file. Commands such as LIST, REPORT FORM, LABEL FORM, and ? that display to the screen without reference to row and column position are console commands. Most of these commands have a TO FILE clause that performs the same function as SET ALTERNATE. Full-screen commands such as @…SAY cannot be echoed to a disk file using SET ALTERNATE. Instead you can use SET PRINTER TO <xcFile> with SET DEVICE TO PRINTER to accomplish this.

SET ALTERNATE has two basic forms. The TO <xcFile> form creates a DOS text file with a default extension of (.txt) and overwrites any other file with the same name. Alternate files are not related to work areas with only one file open at a time. To close an alternate file, use CLOSE ALTERNATE, CLOSE ALL, or SET ALTERNATE TO with no argument.

The on|OFF form controls the writing of console output to the current alternate file. SET ALTERNATE ON begins the echoing of output to the alternate file. SET ALTERNATE OFF suppresses output to the alternate file but does not close it.

Examples :

This example creates an alternate file and writes the results of the ? command to the file for each record in the Customer database file:

 SET ALTERNATE TO Listfile
 SET ALTERNATE ON
 USE Customer NEW
 DO WHILE !EOF()
 ? Customer->Lastname, Customer->City
 SKIP
 ENDDO
 SET ALTERNATE OFF
 CLOSE ALTERNATE
 CLOSE Customer

A single difficulty may be making choose the best between possible methods

You can download a working example prg with a sample .dbf from here :

C5 UI – Advanced

C5 UI – Advanced

ACHOICE() :

Execute a pop-up menu

ACHOICE(<nTop>, <nLeft>, <nBottom>, <nRight>,
    <acMenuItems>,
    [<alSelectableItems> | <lSelectableItems>],
    [<cUserFunction>],
    [<nInitialItem>],
    [<nWindowRow>]) --> nPosition

BROWSE()* :

Browse records within a window

BROWSE([<nTop>], [<nLeft>],
    [<nBottom>], [<nRight>]) --> lSuccess

DBEDIT() :

Browse records in a table format

DBEDIT( [<nTop>], [<nLeft>],
    [<nBottom>], <nRight>],
    [<acColumns>],
    [<cUserFunction>],
    [<acColumnSayPictures> | <cColumnSayPicture>],
    [<acColumnHeaders> | <cColumnHeader>],
    [<acHeadingSeparators> | <cHeadingSeparator>],
    [<acColumnSeparators> | <cColumnSeparator>],
    [<acFootingSeparators> | <cFootingSeparator>],
    [<acColumnFootings> | <cColumnFooting>]) --> NIL

DISPLAY :

Display records to the console

DISPLAY <exp list>
    [TO PRINTER] [TO FILE <xcFile>]
    [<scope>] [WHILE <lCondition>]
    [FOR <lCondition>] [OFF]

LIST :

List records to the console

LIST <exp list>
    [TO PRINTER] [TO FILE <xcFile>]
    [<scope>] [WHILE <lCondition>]
    [FOR <lCondition>] [OFF]

LABEL FORM :

Display labels to the console

LABEL FORM <xcLabel>
    [TO PRINTER] [TO FILE <xcFile>] [NOCONSOLE]
    [<scope>] [WHILE <lCondition>] [FOR <lCondition>]
    [SAMPLE]

REPORT FORM :

Display a report to the console

REPORT FORM <xcReport>
    [TO PRINTER] [TO FILE <xcFile>] [NOCONSOLE]
    [<scope>] [WHILE <lCondition>] [FOR <lCondition>]
    [PLAIN | HEADING <cHeading>] [NOEJECT] [SUMMARY]

TEXT :

Display a literal block of text

TEXT [TO PRINTER] [TO FILE <xcFile>]
    <text>...
ENDTEXT