C5 UI Global Settings

C5 User Interface Global Settings :

SET CENTURY :

Modify the date format to include or omit century digits

SET CENTURY on | OFF | <xlToggle>

SET COLOR* :

Define screen colors

SET COLOR | COLOUR TO [[<standard>]
    [,<enhanced>] [,<border>] [,<background>]
    [,<unselected>]] | (<cColorString>)

SET CONFIRM :

Toggle required exit key to terminate GETs

SET CONFIRM on | OFF | <xlToggle>

SET CONSOLE :

Toggle console display to the screen

SET CONSOLE ON | off | <xlToggle>

SET CURSOR :

Toggle the screen cursor on or off

SET CURSOR ON | off | <xlToggle>

SET DATE :

Set the date format for input and display

SET DATE FORMAT [TO] <cDateFormat>
SET DATE [TO] AMERICAN | ansi | british | french
    | german | italian | japan | usa

SET DECIMALS :

Set the number of decimal places displayed

SET DECIMALS TO [<nDecimals>]

SET DELIMITERS :

Toggle or define GET delimiters

SET DELIMITERS on | OFF | <xlToggle>
SET DELIMITERS TO [<cDelimiters> | DEFAULT]

SET DEVICE :

Direct @…SAYs to the screen or printer

SET DEVICE TO SCREEN | printer

SET EPOCH :

Control the interpretation of dates with no century digits

SET EPOCH TO <nYear>

SET FIXED :

Toggle fixing of the number of decimal digits displayed

SET FIXED on | OFF | <xlToggle>

SETBLINK() :

Toggle asterisk (*) interpretation in SET COLOR

SETBLINK([<lToggle>]) --> lCurrentSetting

SETCOLOR() :

Return the current colors and optionally set new colors

SETCOLOR([<cColorString>]) --> cColorString

SETCURSOR() :

Set the cursor shape

SETCURSOR([<nCursorShape>]) --> nCurrentSetting

SETMODE() :

Change display mode to specified number of rows and columns

SETMODE(<nRows>, <nCols>) --> lSuccess

SETPOS() :

Move the cursor to a new position

SETPOS(<nRow>, <nCol>) --> NIL

C5_SET COLOR

SET COLOR*
 Define screen colors
------------------------------------------------------------------------------
 Syntax

     SET COLOR | COLOUR TO [[<standard>]
        [,<enhanced>] [,<border>] [,<background>]
        [,<unselected>]] | (<cColorString>)

 Arguments

     <standard> is the color that paints all console, full-screen, and
     interface commands and functions when displaying to the screen.  This
     includes commands such as @...PROMPT, @...SAY, and ?; as well as
     functions such as ACHOICE(), DBEDIT(), and MEMOEDIT().

     <enhanced> is the color that paints highlighted displays.  This
     includes GETs with INTENSITY ON, the MENU TO, DBEDIT(), and ACHOICE()
     selection highlight.

     <border> is the color that paints the area around the screen that
     cannot be written to.

     <background> is not currently supported by any machines for which
     Computer Associates provides drivers.  This setting is supplied for
     compatibility purposes only.

     <unselected> is a color pair that provides input focus by displaying
     the current GET in the enhanced color while other GETs are displayed in
     this color.

     <cColorString> is a character string enclosed in parentheses
     containing the color settings.  This facility lets you specify the color
     settings as an expression in place of a literal string or macro
     variable.

     SET COLOR TO with no argument restores the default colors to W/N, N/W,
     N, N, N/W.

 Description

     SET COLOR, a command synonym for the SETCOLOR() function, defines colors
     for subsequent screen painting activity.  Each SET COLOR command
     specifies a list of color settings for the five types of screen painting
     activity.  Each setting is a foreground and background color pair
     separated by the slash (/) character.  Foreground defines the color of
     characters displayed on the screen.  Background defines the color
     displayed behind the character.  Spaces and nondisplay characters
     display as background only.

     In addition to color, a foreground setting can have an attribute, high
     intensity or blinking.  With a monochrome display, high intensity
     enhances brightness of painted text.  With a color display, high
     intensity changes the hue of the specified color making it a different
     color.  For example, N displays foreground text as black where N+
     displays the same text as gray.  High intensity is denoted by +.  The
     blinking attribute causes the foreground text to flash on and off at a
     rapid interval.  Blinking is denoted with *.  An attribute character can
     occur anywhere in a setting, but is always applied to the foreground
     color regardless where it occurs.

     Each color can be specified using either a letter or a number, but
     numbers and letters cannot be mixed within a setting.  Note that numbers
     are supplied for compatibility purposes and are not recommended.

     All settings are optional.  If a setting is skipped, its previous value
     is retained with only new values set.  Skipping a foreground or
     background color within a setting sets the color to black.

     The following colors are supported:

     Color Table
     ------------------------------------------------------------------------
     Color          Letter    Number  Monochrome
     ------------------------------------------------------------------------
     Black          N, Space  0       Black
     Blue           B         1       Underline
     Green          G         2       White
     Cyan           BG        3       White
     Red            R         4       White
     Magenta        RB        5       White
     Brown          GR        6       White
     White          W         7       White
     Gray           N+        8       Black
     Bright Blue    B+        9       Bright Underline
     Bright Green   G+        10      Bright White
     Bright Cyan    BG+       11      Bright White
     Bright Red     R+        12      Bright White
     Bright Magenta RB+       13      Bright White
     Yellow         GR+       14      Bright White
     Bright White   W+        15      Bright White
     Black          U                 Underline
     Inverse Video  I                 Inverse Video
     Blank          X                 Blank
     ------------------------------------------------------------------------

     SET COLOR is a compatibility command and is not recommended.  It is
     superseded by the SETCOLOR() function which can return the current color
     as well as set a new color.

 Notes

     .  Monochrome monitors:  Color is not supported on monochrome
        monitors.  Clipper, however, supports the monochrome attributes
        inverse video (I) and underlining (U).

     .  Screen drivers: SET COLOR TO, using numbers, may not be
        supported by screen drivers other than the default screen driver.

 Examples

     .  This example uses the unselected setting to make the current
        GET red on white while the rest are black on white:

        cColor:= "W/N,R/W,,,N/W"
        SET COLOR TO (cColor)
        cOne := cTwo := SPACE(10)
        @ 1, 1 SAY "Enter One: " GET cOne
        @ 2, 1 SAY "Enter Two: " GET cTwo
        READ

     .  In this example a user-defined function gets a password from
        the user using the blank (X) enhanced setting to hide the password as
        the user types:

        IF !DialogPassWord(12, 13, "W+/N", "FUNSUN", 3)
           ? "Sorry, your password failed"
           QUIT
        ENDIF

        FUNCTION DialogPassWord( nRow, nCol, ;
               cStandard, cPassword, nTries )
           LOCAL nCount := 1, cColor := SETCOLOR()
           SET COLOR TO (cStandard + ", X")      // Blank input
           //
           DO WHILE nCount < nTries
              cUserEntry:= SPACE(6)
              @ nRow, nCol SAY  "Enter password: " GET ;
                       cUserEntry
              READ
              //
              IF LASTKEY() == 27
                 SET COLOR TO (cColor)
                 RETURN .F.

              ELSEIF cUserEntry == cPassword
                 SET COLOR TO (cColor)
                 RETURN .T.
              ELSE
                 nCount++
              ENDIF
           ENDDO
           //
           SET COLOR TO (cColor)
           RETURN .F.

 Files   Library is CLIPPER.LIB.

See Also: @…GET @…SAY ISCOLOR() SETCOLOR() SETBLINK()



C5 Commands

 ?|??            Display one or more values to the console
 @...BOX         Draw a box on the screen
 @...CLEAR       Clear a rectangular region of the screen
 @...GET         Create a new Get object and display it
 @...PROMPT      Paint a menu item and define a message
 @...SAY         Display data at a specified screen or printer row and column
 @...TO          Draw a single- or double-line box
 ACCEPT*         Place keyboard input into a memory variable
 APPEND BLANK    Add a new record to the current database file
 APPEND FROM     Import records from a database (.dbf) file or ASCII text file
 AVERAGE         Average numeric expressions in the current work area
 CALL*           Execute a C or Assembler procedure
 CANCEL*         Terminate program processing
 CLEAR ALL*      Close files and release public and private variables
 CLEAR GETS      Release Get objects from the current GetList array
 CLEAR MEMORY    Release all public and private variables
 CLEAR SCREEN    Clear the screen and return the cursor home
 CLEAR TYPEAHEAD Empty the keyboard buffer
 CLOSE           Close a specific set of files
 COMMIT          Perform a solid-disk write for all active work areas
 CONTINUE        Resume a pending LOCATE
 COPY FILE       Copy a file to a new file or to a device
 COPY STRUCTURE  Copy the current .dbf structure to a new database (.dbf) file
 COPY STRU EXTE  Copy field definitions to a .dbf file
 COPY TO         Export records to a database (.dbf) file or ASCII text file
 COUNT           Tally records to a variable
 CREATE          Create an empty structure extended (.dbf) file
 CREATE FROM     Create a new .dbf file from a structure extended file
 DELETE          Mark records for deletion
 DELETE FILE     Remove a file from disk
 DELETE TAG      Delete a tag
 DIR*            Display a listing of files from a specified path
 DISPLAY         Display records to the console
 EJECT           Advance the printhead to top of form
 ERASE           Remove a file from disk
 FIND*           Search an index for a specified key value
 GO              Move the pointer to the specified identity
 INDEX           Create an index file
 INPUT*          Enter the result of an expression into a variable
 JOIN            Create a new database file by merging from two work areas
 KEYBOARD        Stuff a string into the keyboard buffer
 LABEL FORM      Display labels to the console
 LIST            List records to the console
 LOCATE          Search sequentially for a record matching a condition
 MENU TO         Execute a lightbar menu for defined PROMPTs
 NOTE*           Place a single-line comment in a program file
 PACK            Remove deleted records from a database file
 QUIT            Terminate program processing
 READ            Activate full-screen editing mode using Get objects
 RECALL          Restore records marked for deletion
 REINDEX         Rebuild open indexes in the current work area
 RELEASE         Delete public and private memory variables
 RENAME          Change the name of a file
 REPLACE         Assign new values to field variables
 REPORT FORM     Display a report to the console
 RESTORE         Retrieve memory variables from a memory (.mem) file
 RESTORE SCREEN* Display a saved screen
 RUN             Execute a DOS command or program
 SAVE            Save variables to a memory (.mem) file
 SAVE SCREEN*    Save the current screen to a buffer or variable
 SEEK            Search an order for a specified key value
 SELECT          Change the current work area
 SET ALTERNATE   Echo console output to a text file
 SET BELL        Toggle sounding of the bell during full-screen operations
 SET CENTURY     Modify the date format to include or omit century digits
 SET COLOR*      Define screen colors
 SET CONFIRM     Toggle required exit key to terminate GETs
 SET CONSOLE     Toggle console display to the screen
 SET CURSOR      Toggle the screen cursor on or off
 SET DATE        Set the date format for input and display
 SET DECIMALS    Set the number of decimal places to be displayed
 SET DEFAULT     Set the CA-Clipper default drive and directory
 SET DELETED     Toggle filtering of deleted records
 SET DELIMITERS  Toggle or define GET delimiters
 SET DESCENDING  Change the descending flag of the controlling order
 SET DEVICE      Direct @...SAYs to the screen or printer
 SET EPOCH       Control the interpretation of dates with no century digits
 SET ESCAPE      Toggle Esc as a READ exit key
 SET EXACT*      Toggle exact matches for character strings
 SET EXCLUSIVE*  Establish shared or exclusive USE of database files
 SET FILTER      Hide records not meeting a condition
 SET FIXED       Toggle fixing of the number of decimal digits displayed
 SET FORMAT*     Activate a format when READ is executed
 SET FUNCTION    Assign a character string to a function key
 SET INDEX       Open one or more order bags in the current work area
 SET INTENSITY   Toggle enhanced display of GETs and PROMPTs
 SET KEY         Assign a procedure invocation to a key
 SET MARGIN      Set the page offset for all printed output
 SET MEMOBLOCK   Change the block size for memo files
 SET MESSAGE     Set the @...PROMPT message line row
 SET OPTIMIZE    Change the setting that optimizes using open orders
 SET ORDER       Select the controlling order
 SET PATH        Specify the CA-Clipper search path for opening files
 SET PRINTER     Toggle echo of output to printer or set the print destination
 SET PROCEDURE*  Compile procedures and functions into the current object file
 SET RELATION    Relate two work areas by a key value or record number
 SET SCOPE       Change the boundaries for scoping keys in controlling order
 SET SCOPEBOTTOM Change bottom boundary for scoping keys in controlling order
 SET SCOPETOP    Change top boundary for scoping keys in controlling order
 SET SCOREBOARD  Toggle the message display from READ or MEMOEDIT()
 SET SOFTSEEK    Toggle relative seeking
 SET TYPEAHEAD   Set the size of the keyboard buffer
 SET UNIQUE*     Toggle inclusion of non-unique keys into an index
 SET WRAP*       Toggle wrapping of the highlight in menus
 SKIP            Move the record pointer to a new position
 SORT            Copy to a database (.dbf) file in sorted order
 STORE*          Assign a value to one or more variables
 SUM             Sum numeric expressions and assign results to variables
 TEXT*           Display a literal block of text
 TOTAL           Summarize records by key value to a database (.dbf) file
 TYPE            Display the contents of a text file
 UNLOCK          Release file/record locks set by the current user
 UPDATE          Update current database file from another database file
 USE             Open an existing database (.dbf) and its associated files
 WAIT*           Suspend program processing until a key is pressed
 ZAP             Remove all records from the current database file

 

Nested Hashes

*-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.
/*
 Since a <Value> of a hash's pair may be in any scalar or complex type,
 a hash may be nested by assigning an another hash to a hash <Value>. 

*/
PROCEDURE Main()
   SET COLO TO "W/B"
   SetMode( 50, 120 )

   CLS

   hSouth := { 'Argentina' => "Buenos Aires",;
               'Brasil'    => "Brasilia",;
               'Chile'     => "Santiago" }

   hNorth:= { 'USA'    => "Washington DC",;
              'Canada' => "Ottawa",; 
              'Mexico' => "Mexico City" } 

   * a hash contains two hashes :

   hAmerica := { "America" => { "North" => hNorth,;
                                "South" => hSouth } } 

   * Standart array indexing syntax :

   ? hAmerica[ "America", "North", "USA" ] // Washington DC

   * Alternate syntax to indexing :

   ? hAmerica[ "America"][ "South" ][ "Chile" ] // Santiago

   ?
   @ MAXROW(), 0
   WAIT "EOF HashNest.prg"

RETURN // HashNest.Main()
*-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.

Hash vs Table

Consider a table for customers records with two character fields : Customer ID and customer name:

Cust_ID Cust_Name
CC001 Pierce Firth
CC002 Stellan Taylor
CC003 Chris Cherry
CC004 Amanda Baranski

 It’s known all possible and necessary operations on a table: APPEND, DELETE, SEEK and so on; by the way, for SEEK we need an index file also.

Listing this table is quite simple:

USE CUSTOMER
WHILE .NOT. EOF()
   ? CUST_ID, CUST_NAME
   DBSKIP()
ENDDO

 If our table is sufficiently small, we can find a customer record without index and SEEK :

LOCATE FOR CUST_ID = “CC003”
? CUST_ID, CUST_NAME

If we want all our data will stand in memory and we could manage it more simple and quick way, we would use an array ( with some considerations about size of table; if it is too big, this method will be problematic ) :

aCustomer := {}    // Declare / define an empty array
USE CUSTOMER
WHILE .NOT. EOF()
   AADD(aCustomer, { CUST_ID, CUST_NAME } )
   DBSKIP()
ENDDO
Traversing this array is quite simple :

FOR nRecord := 1 TO LEN( aCustomer )

    ? aCustomer[ nRecord, 1 ], aCustomer[ nRecord, 2 ]
NEXT
or :

a1Record := {}

FOR EACH a1Record IN aCustomer
   ? a1Record[ 1 ], a1Record[ 2 ]
NEXT

And locating a specific record too:

nRecord := ASCAN( aCustomer, { | a1Record | a1Record[ 1 ] == “CC003” } )

? aCustomer[ nRecord, 1 ], aCustomer[ nRecord, 2 ]

A lot of array functions are ready to use for maintain this array : ADEL(), AADD(), AINS() etc …

Now, let’s see how we could use a hash for achieve this job :

hCustomer := { => } // Declare / define an empty hash

USE CUSTOMER
WHILE .NOT. EOF()
   hCustomer[ CUST_ID ] := CUST_NAME
   DBSKIP()
ENDDO
Let’s traversing :

h1Record := NIL

FOR EACH h1Record IN hCustomer
   ? h1Record: __ENUMKEY(),h1Record:__ENUMVALUE()
NEXT

Now, we have a bit complicate our job; a few field addition to the table :

No: Field Name Type Width  Dec Decription

1

 CUST_ID

C

 5

0

Id ( Code )

2

 CUST_NAME

C

10

0

Name

3

 CUST_SNAM

C

10

0

Surname

4

 CUST_FDAT

D

 8

0

First date

5

 CUST_ACTV

L

 1

0

Is active ?

6

 CUST_BLNCE

N

11

2

Balance

 While <key> part of an element of a hash may be C / D / N / L type; <xValue> part of hash too may be ANY type of data, exactly same as arrays.

So, we can make fields values other than first ( ID) elements of an array:

hCustomer := { => } // Declare / define an empty hash
USE CUSTOMER
WHILE .NOT. EOF()
   a1Data:= { CUST_NAME, CUST_SNAM, CUST_FDAT, CUST_ACTV, CUST_BLNCE }
   hCustomer[ CUST_ID ] := a1Data
   DBSKIP()
ENDDO
Let’s traversing :

h1Record := NIL

FOR EACH h1Record IN hCustomer
   a1Key  := h1Record:__ENUMKEY()
   a1Data := h1Record:__ENUMVALUE()
   ? a1Key
   AEVAL( a1Data, { | x1 | QQOUT( x1 ) } )
NEXT
*-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._
/*
Hash vs Tables
 
*/
#define NTrim( n ) LTRIM( STR( n ) )
#define cLMarj SPACE( 3 )
PROCEDURE Main()

  SET DATE GERM
  SET CENT ON
  SET COLO TO "W/B"
  SetMode( 40, 120 )
 
  CLS
 
  hCustomers := { => } // Declare / define an empty PRIVATE hash
 
  IF MakUseTable() 
 
     Table2Hash()
 
     * Here the hash hCustomers may be altered in any way
 
     ZAP
 
     Hash2Table()
 
  ELSE
      ? "Couldn't make / USE table"
  ENDIF
 
  ?
  @ MAXROW(), 0
  WAIT "EOF HashVsTable.prg"
 
RETURN // HashVsTable.Main()
*-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.
PROCEDURE Table2Hash()
   hCustomers := { => } 
   WHILE .NOT. EOF()
     hCustomers[ CUST_ID ] := CUST_SNAM
     DBSKIP()
   ENDDO
 
   ListHash( hCustomers, "A hash transferred from a table (single value)" )
 
   hCustomers := { => } // Declare / define an empty hash
   DBGOTOP()
   WHILE .NOT. EOF()
      hCustomers[ CUST_ID ] := { CUST_NAME, CUST_SNAM, CUST_FDAT, CUST_ACTV, CUST_BLNCE }
      DBSKIP()
   ENDDO
 
   ListHash( hCustomers, "A hash transferred from a table (multiple values)" )
 
RETURN // Table2Hash()

*-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.

PROCEDURE Hash2Table()
   LOCAL h1Record,;
         c1Key,;
         a1Record,;
         n1Field
 
   FOR EACH h1Record IN hCustomers
      c1Key := h1Record:__ENUMKEY()
      a1Record := h1Record:__ENUMVALUE()
      DBAPPEND()
      FIELDPUT( 1, c1Key )
      AEVAL( a1Record, { | x1, n1 | FIELDPUT( n1 + 1 , x1 ) } )
   NEXT h1Record
   DBGOTOP()
 
   ?
   ? "Data trasferred from hash to table :"
   ?
   WHILE ! EOF()
      ? STR( RECN(), 5), ''
      FOR n1Field := 1 TO FCOUNT()
         ?? FIELDGET( n1Field ), ''
      NEXT n1Field
      DBSKIP()
   ENDDO 
 
RETURN // Hash2Table()

*-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.

PROCEDURE ListHash( hHash, cComment )
 
  LOCAL x1Pair
 
  cComment := IF( HB_ISNIL( cComment ), '', cComment )
 
  ? 
  ? cComment // , "-- Type :", VALTYPE( hHash ), "size:", LEN( hHash )
  ?
  IF HB_ISHASH( hHash ) 
     FOR EACH x1Pair IN hHash
        nIndex := x1Pair:__ENUMINDEX()
        x1Key := x1Pair:__ENUMKEY()
        x1Value := x1Pair:__ENUMVALUE()
        ? cLMarj, NTrim( nIndex ) 
*       ?? '', VALTYPE( x1Pair )
        ?? '', x1Key, "=>"
*       ?? '', VALTYPE( x1Key ) 
*       ?? VALTYPE( x1Value ) 
        IF HB_ISARRAY( x1Value ) 
           AEVAL( x1Value, { | x1 | QQOUT( '', x1 ) } )
        ELSE 
           ?? '', x1Value
        ENDIF 
     NEXT
  ELSE
    ? "Data type error; Expected hash, came", VALTYPE( hHash ) 
  ENDIF HB_ISHASH( hHash )
RETURN // ListHash()
*-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.

FUNCTION MakUseTable() // Make / USE table
 
 LOCAL cTablName := "CUSTOMER.DBF"
 LOCAL lRetval, aStru, aData, a1Record 
 
 IF FILE( cTablName ) 
    USE (cTablName)
 ELSE
    aStru := { { "CUST_ID", "C", 5, 0 },;
               { "CUST_NAME", "C", 10, 0 },;
               { "CUST_SNAM", "C", 10, 0 },;
               { "CUST_FDAT", "D", 8, 0 },;
               { "CUST_ACTV", "L", 1, 0 },;
               { "CUST_BLNCE", "N", 11, 2 } }
    * 
    * 5-th parameter of DBCREATE() is alias - 
    * if not given then WA is open without alias 
    *                              ^^^^^^^^^^^^^ 
    DBCREATE( cTablName, aStru, , .F., "CUSTOMER" ) 
 
    aData := { { "CC001", "Pierce", "Firth", 0d20120131, .T., 150.00 },; 
               { "CC002", "Stellan", "Taylor", 0d20050505, .T., 0.15 },;
               { "CC003", "Chris", "Cherry", 0d19950302, .F., 0 },;
               { "CC004", "Amanda", "Baranski", 0d20011112, .T., 12345.00 } }
 
    FOR EACH a1Record IN aData
        CUSTOMER->(DBAPPEND())
        AEVAL( a1Record, { | x1, nI1 | FIELDPUT( nI1, X1 ) } )
    NEXT a1Record 
    DBGOTOP()
 
 ENDIF 
 
 lRetval := ( ALIAS() == "CUSTOMER" )
 
RETURN lRetval // MakUseTable()

*-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._
 
HashVsTable

Hash Basics

Definition:

In general, a Hash Table, or Hash Array, or Associative array, or shortly Hash is an array- like data structure, to store some data with an associated key for each; so, ‘atom’ of a hash is a pair of a ‘key’ with a ‘value’. A hash system needs to perform at least three operations:

–      add a new pair,

–      access to value via key

–      the search and delete operations on a key pair

In Harbour, a hash is simply a special array, or more precisely a “keyed” array with special syntax with a set of functions.

Building:

The “=>” operator can be used to indicate literally the relation between <key> <value> pair: <key> => <value>

 We can define and initialize a hash by this “literal” way :

 hDigits_1 := { 1 => 1, 2  => 2, 3  => 3, 4  => 4 }

 or by a special function call:

 hDigits_1 := HB_HASH( 1, 1, 2, 2, 3, 3, 4, 4 )

 Using “add” method may be another way :

hDigits_1 := { => } // Build an empty hash
hDigits_1[ 1] := 1

hDigits_1[ 2] := 2

hDigits_1[ 3] := 3

hDigits_1[ 4] := 4

In this method while evaluating each of above assignments, if given key exits in hash, will be replaced its value; else add a new pair to the hash.

In addition, data can be added to a hash by extended “+=” operator:

   hCountries := { 'Argentina' => "Buenos Aires" }
   hCountries += { 'Brasil'    => "Brasilia" }
   hCountries += { 'Chile'     => "Santiago" }
   hCountries += { 'Mexico'    => "Mexico City" }

Hashs may add ( concatenate ) each other by extended “+” sign :

   hFruits := { "fruits" => { "apple", "chery", "apricot" } }
   hDays   := { "days"   => { "sunday", "monday" } } 
   hDoris := hFruits + hDays

Note:  This “+” and “+=” operators depends xHB lib and needs to xHB lib and xHB.ch.

Typing :

<key> part of a hash may be any legal scalar type : C, D, L, N; and <value> part may be in addition scalar types, any complex type ( array or hash ).

Correction : This definition is wrong ! The correct is :

<key> entry key; can be of type: number, date, datetime, string, pointer.

Corrected at : 2015.12.08; thanks to Marek.

hDigits_2 := {  1  => “One”,  2  => “Two”,  3  => “Three”,  4  => “Four” }

hDigits_3 := { "1" => "One", "2" => "Two", "3" => "Three", "4" => "Four" }
hDigits_4 := { "1" => "One",  2  => "Two",  3  => "Three", "4" => "Four" }
hDigits_5 := {  1  => "One",  1  => "Two",  3  => "Three",  4  => "Four"

All of these examples are legal. As a result, a pair record of a hash may be:

–      Numeric key, numeric value ( hDigits_1 )

–      Numeric key, character value ( hDigits_2 )

–      Character key, character value ( hDigits_3 )

–      Mixed type key ( hDigits_4 )

Duplicate keys (as seen in hDigits_5) is permitted to assign, but not give a result such as double keyed values: LEN( hDigits_5 ) is 3, not 4; because first pair replaced by second due to has same key.

Consider a table-like data for customers records with two character fields: Customer ID and customer name:

Cust_ID Cust_Name
CC001 Pierce Firth
CC002 Stellan Taylor
CC003 Chris Cherry
CC004 Amanda Baranski

We can build a hash with this data :

  hCustomers := { "CC001" => "Pierce Firth",;
 "CC002" => "Stellan Taylor",;
 "CC003" => "Chris Cherry",;
 "CC004" => "Amanda Baranski" }

and list it:

   ?
   ? "Listing a hash :"
   ?
   h1Record := NIL
   FOR EACH h1Record IN hCustomers
      ? cLMarj, h1Record:__ENUMKEY(), h1Record:__ENUMVALUE()
   NEXT

 Accessing a specific record is easy :

 hCustomers[ "CC003" ] // Chris Cherry
*-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.
/*
Hash Basics

*/
#include "xhb.ch"
#define NTrim( n ) LTRIM( STR( n ) )
PROCEDURE Main()
 SET DATE GERM
 SET CENT ON
 SET COLO TO "W/B"

 cLMarj := SPACE( 3 )

 CLS

 hDigits_1 := { => } // Build an empty hash

 hDigits_1[ 1 ] := 1
 hDigits_1[ 2 ] := 2
 hDigits_1[ 3 ] := 3
 hDigits_1[ 4 ] := 4

 ListHash( hDigits_1, "Digits_1" )

 hDigits_2 := HB_HASH( 1, 1, 2, 2, 3, 3, 4, 4 )

 ListHash( hDigits_2, "Digits_2" )

 hDigits_3 := { 1 => 1,;
 2 => 2,;
 3 => 3,;
 4 => 4 }
 ListHash( hDigits_3, "Digits_3" )

 hDigits_4 := { 1 => "One",;
 2 => "Two",;
 3 => "Three",;
 4 => "Four" }
ListHash( hDigits_4, "Digits_4" )

 hDigits_5 := { "1" => "One",;
 "2" => "Two",;
 "3" => "Three",;
 "4" => "Four" }
 ListHash( hDigits_5, "Digits_5" )

 hDigits_6 := { "1" => "One",;
 2 => "Two",;
 3 => "Three",;
 "4" => "Four" }
 ListHash( hDigits_6, "Digits_6" )

 hDigits_7 := { 1 => "One",;
 1 => "Two",; // This line replace to previous due to same key 
 3 => "Three",;
 4 => "Four" }
 ListHash( hDigits_7, "Digits_7" )

 * WAIT "EOF digits"

 hCustomers := { "CC001" => "Pierce Firth",;
 "CC002" => "Stellan Taylor",;
 "CC003" => "Chris Cherry",;
 "CC004" => "Amanda Baranski" }
 ListHash( hCustomers, "A hash defined and initialized literally" )
 ?
 ? "Hash value with a specific key (CC003) :", hCustomers[ "CC003" ] // Chris Cherry
 ?
 cKey := "CC003" 
 ?
 ? "Locating a specific record in an hash by key (", cKey, ":"
 ?
 c1Data := hCustomers[ cKey ]
 ? cLMarj, c1Data

 hCountries := { 'Argentina' => "Buenos Aires" }
 hCountries += { 'Brasil' => "Brasilia" }
 hCountries += { 'Chile' => "Santiago" }
 hCountries += { 'Mexico' => "Mexico City" }

 ListHash( hCountries, "A hash defined and initialized by adding with '+=' operator:" )

 hFruits := { "fruits" => { "apple", "chery", "apricot" } }
 hDays := { "days" => { "sunday", "monday" } } 

 hDoris := hFruits + hDays

 ListHash( hDoris, "A hash defined and initialized by concataned two hash with '+' operator:" )

 ?
 @ MAXROW(), 0
 WAIT "EOF HashBasics.prg"

RETURN // HashBasics.Main()
*-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.
PROCEDURE ListHash( hHash, cComment )

 LOCAL x1Pair := NIL

 cComment := IF( HB_ISNIL( cComment ), '', cComment )

 ? 
 ? cComment, "-- Type :", VALTYPE( hHash ), "size:", NTrim ( LEN( hHash ) ) 
 ?
 FOR EACH x1Pair IN hHash
    nIndex := x1Pair:__ENUMINDEX()
    x1Key := x1Pair:__ENUMKEY()
    x1Value := x1Pair:__ENUMVALUE()
    ? cLMarj, NTrim( nIndex ) 
*   ?? '', VALTYPE( x1Pair )
    ?? '', x1Key, "=>"
*   ?? '', VALTYPE( x1Key ) 
*   ?? VALTYPE( x1Value ) 
    IF HB_ISARRAY( x1Value ) 
       AEVAL( x1Value, { | x1 | QQOUT( '', x1 ) } )
    ELSE 
       ?? '', x1Value
    ENDIF 
 NEXT

RETURN // ListHash()
*-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.-._.

HashBass

C5 Environment Commands and Functions

Commands :

SET BELL :

Toggle automatic sounding of the bell during full-screen operations

SET BELL on | OFF | <xlToggle>

SET COLOR :

Define screen colors

SET COLOR | COLOUR TO [ [<standard>]
    [, <enhanced>] [, <border>] [, <background> ]
    [, <unselected>]] | ( <cColorString> )

SET DEFAULT :

Set the default drive and directory

SET DEFAULT TO [ <xcPathspec> ]

SET FUNCTION :

Assign a character string to a function key

SET FUNCTION <nFunctionKey> TO <cString>

SET TYPEAHEAD :

Set the size of the keyboard buffer

SET TYPEAHEAD TO <nKeyboardSize>

Functions :

CURDIR() :

Return the current DOS directory

CURDIR( [ <cDrivespec> ] ) --> cDirectory

DISKSPACE() :

Return the space available on a specified disk

DISKSPACE( [ <nDrive> ] ) --> nBytes

FKLABEL()* :

Return function key name

FKLABEL( <nFunctionKey> ) --> cKeyLabel

FKMAX()* :

Return number of function keys as a constant

FKMAX() --> nFunctionKeys

GETENV() :

Retrieve the contents of a DOS environment variable

GETENV( <cEnvironmentVariable> ) --> cString

ISCOLOR() :

Determine if the current computer has color compatibility

ISCOLOR() | ISCOLOUR() --> lBoolean

MAXROW() :

Determine the maximum visible screen row

MAXROW() --> nRow

MAXCOL() :

Determine the maximum visible screen column

MAXCOL() --> nColumn

MEMORY() :

Determine the amount of available free pool memory

MEMORY( <nMemoryType> ) --> nKbytes

NOSNOW() :

Toggle snow position

NOSNOW( <lToggle> ) --> NIL

OS() :

Return the operating system name

OS() --> cOSName

SET() :

Inspect or change a global setting

SET( <nSpecifier>, [<expNewSetting>], [<lOpenMode> ] )
      --> CurrentSetting

TONE() :

Sound a speaker tone for a specified frequency and duration

TONE( <nFrequency>, <nDuration> ) --> NIL

VERSION() :

Returns Clipper Compiler version

VERSION() --> cVersion

C5 UI Commands & Functions

C5 User Interface Commands and Functions

Global Settings :

SET CENTURY :

Modify the date format to include or omit century digits

SET CENTURY on | OFF | <xlToggle>

SET COLOR* :

Define screen colors

SET COLOR | COLOUR TO [[<standard>]
    [,<enhanced>] [,<border>] [,<background>]
    [,<unselected>]] | (<cColorString>)

SET CONFIRM :

Toggle required exit key to terminate GETs

SET CONFIRM on | OFF | <xlToggle>

SET CONSOLE :

Toggle console display to the screen

SET CONSOLE ON | off | <xlToggle>

SET CURSOR :

Toggle the screen cursor on or off

SET CURSOR ON | off | <xlToggle>

SET DATE :

Set the date format for input and display

SET DATE FORMAT [TO] <cDateFormat>
SET DATE [TO] AMERICAN | ansi | british | french
    | german | italian | japan | usa

SET DECIMALS :

Set the number of decimal places displayed

SET DECIMALS TO [<nDecimals>]

SET DELIMITERS :

Toggle or define GET delimiters

SET DELIMITERS on | OFF | <xlToggle>
SET DELIMITERS TO [<cDelimiters> | DEFAULT]

SET DEVICE :

Direct @…SAYs to the screen or printer

SET DEVICE TO SCREEN | printer

SET EPOCH :

Control the interpretation of dates with no century digits

SET EPOCH TO <nYear>

SET FIXED :

Toggle fixing of the number of decimal digits displayed

SET FIXED on | OFF | <xlToggle>

SETBLINK() :

Toggle asterisk (*) interpretation in SET COLOR

SETBLINK([<lToggle>]) --> lCurrentSetting

SETCOLOR() :

Return the current colors and optionally set new colors

SETCOLOR([<cColorString>]) --> cColorString

SETCURSOR() :

Set the cursor shape

SETCURSOR([<nCursorShape>]) --> nCurrentSetting

SETMODE() :

Change display mode to specified number of rows and columns

SETMODE(<nRows>, <nCols>) --> lSuccess

SETPOS() :

Move the cursor to a new position

SETPOS(<nRow>, <nCol>) --> NIL

User Input :

CLEAR TYPEAHEAD :

Empty the keyboard buffer

CLEAR TYPEAHEAD

INKEY() :

Extract a character from the keyboard buffer

 
INKEY( [ <nSeconds> ] ) --> nInkeyCode

KEYBOARD :

Stuff a string into the keyboard buffer

KEYBOARD <cString>

LASTKEY() :

Return the INKEY() value of the last key in the buffer

LASTKEY() --> nInkeyCode

NEXTKEY() :

Read the pending key in the keyboard buffer

NEXTKEY() --> nInkeyCode

SET TYPEAHEAD :

Set the size of the keyboard buffer

SET TYPEAHEAD TO <nKeyboardSize>

Basic :

?/?? :

Display one or more values to the console

? | ?? [<exp list>]

@…BOX :

Draw a box on the screen

@ <nTop>, <nLeft>, <nBottom>, <nRight>
  BOX <cBoxString> [COLOR <cColorString>]

@…CLEAR :

Clear a rectangular region of the screen

@ <nTop>, <nLeft> [CLEAR
  [TO <nBottom>, <nRight>]]

@…SAY :

Display data at a specified screen or printer row and column

@ <nRow>, <nCol>
    [SAY <exp>
    [PICTURE <cSayPicture>]
    [COLOR <cColorString>]]
    GET <idVar>
    [PICTURE <cGetPicture>]
    [COLOR <cColorString>]
    [WHEN <lPreExpression>]
    [RANGE* <dnLower>, <dnUpper>] |
    [VALID <lPostExpression>]

@…TO :

Draw a single or double line box

@ <nTop>, <nLeft>
    TO <nBottom>, <nRight> [DOUBLE] [COLOR
    <cColorString>]

ACCEPT :

Place keyboard input into a memory variable

ACCEPT [<expPrompt>] TO <idVar>

INPUT :

Enter the result of an expression into a variable

INPUT [<expPrompt>] TO <idVar>

 

ALERT() :

Display a simple modal dialog box

ALERT( <cMessage>, [<aOptions>] ) --> nChoice

CLEAR SCREEN :

Clear the screen and home the cursor

CLEAR [SCREEN] | CLS

COL() :

Return the screen cursor column position

COL() --> nCol

COLORSELECT()

                Activate attribute in current color settings

   COLORSELECT(<nColorIndex>) --> NIL

DEVOUT() :

Write a value to the current device

DEVOUT(<exp>, [<cColorString>]) --> NIL

DEVOUTPICT() :

Write a value to the current device using a picture clause

DEVOUTPICT(<exp>, <cPicture>, [<cColorString>]) --> NIL

           DEVPOS() :

Move the cursor or printhead to a new position depending on the

current device

        DEVPOS(<nRow>, <nCol>) --> NIL

DISPBEGIN() :

Begin buffering screen output

DISPBEGIN() --> NIL

DISPBOX() :

Display a box on the screen

DISPBOX(<nTop>, <nLeft>, <nBottom>, <nRight>,
    [<cnBoxString>], [<cColorString>]) --> NIL

DISPCOUNT() :

Return the number of pending DISPEND() requests

DISPCOUNT() --> nDispCount

DISPEND() :

Display buffered screen updates

DISPEND() --> NIL

DISPOUT() :

Write a value to the display

DISPOUT(<exp>, [<cColorString>]) --> NIL

OUTERR() :

Write a list of values to the standard error device

OUTERR(<exp list>) --> NIL

OUTSTD() :

Write a list of values to the standard output device

OUTSTD(<exp list>) --> NIL

QOUT() :

Display a list of expressions to the console

QOUT([<exp list>]) --> NIL
QQOUT([<exp list>]) --> NIL

RESTORE SCREEN* :

Display a saved screen

RESTORE SCREEN [FROM <cScreen>]

RESTSCREEN() :

Display a saved screen region to a specified location

RESTSCREEN([<nTop>], [<nLeft>],
    [<nBottom>], [<nRight>], <cScreen>) --> NIL

ROW() :

Return the screen row position of the cursor

ROW() --> nRow

SAVE SCREEN* :

Save current screen to a buffer or variable

SAVE SCREEN [TO <idVar>]

SAVESCREEN() :

Save a screen region for later display

SAVESCREEN([<nTop>], [<nLeft>],
    [<nBottom>], [<nRight>]) --> cScreen

SCROLL() :

Scroll a screen region up or down

SCROLL([<nTop>], [<nLeft>],
     [<nBottom>], [<nRight>], [<nVert>] [<nHoriz>])
 --> NIL

TYPE :

Display or print the contents of a text file

TYPE <xcFile> [TO PRINTER] [TO FILE <xcOutFile>]

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

GET System :

Standard :

@…GET :

Create a new Get object and display it on the screen

@ <nRow>, <nCol>
    [SAY <exp>
    [PICTURE <cSayPicture>]
    [COLOR <cColorString>]]
    GET <idVar>
    [PICTURE <cGetPicture>]
    [COLOR <cColorString>]
    [WHEN <lPreExpression>]
    [RANGE* <dnLower>, <dnUpper>] |
    [VALID <lPostExpression>]

CLEAR GETS :

Release Get objects from the current GetList array

CLEAR GETS

READ :

Activate full-screen editing mode using Get objects

READ [SAVE]

READEXIT() :

Toggle Uparrow and Downarrow as READ exit keys

READEXIT([<lToggle>]) --> lCurrentState

READINSERT() :

Toggle the current insert mode for READ and MEMOEDIT()

READINSERT([<lToggle>]) --> lCurrentMode

READKEY()* :

Determine what key was used to terminate a READ

READKEY() --> nReadkeyCode

READMODAL() :

Activate a full-screen editing mode for a GetList

READMODAL(<aGetList>) --> NIL

READVAR() :

Return the current GET/MENU variable name

READVAR() --> cVarName

SET ESCAPE :

Toggle Esc as a READ exit key

SET ESCAPE ON | off | <xlToggle>

SET FORMAT :

Activate a format when READ is executed

SET FORMAT TO [<idProcedure>[.<ext>]]

SET INTENSITY :

Toggle enhanced display of GETs and PROMPTs

SET INTENSITY ON | off | <xlToggle>

SET SCOREBOARD :

Toggle the message display from READ or MEMOEDIT()

SET SCOREBOARD ON | off | <xlToggle>

UPDATED() :

Determine if any GET changed during a READ

UPDATED() --> lChange

Getsys.prg Functions :

GETACTIVE() :

Return the currently active Get object

GETACTIVE() --> objGet

GETAPPLYKEY() :

Apply a key to a Get object from within a Get reader

GETAPPLYKEY(<oGet>, <nKey>) --> NIL

GETDOSETKEY() :

Process SET KEY during Get editing

GETDOSETKEY(<oGet>) --> NIL

GETPOSTVALIDATE() :

Postvalidate the current Get object

GETPOSTVALIDATE(<oGet>) --> lSuccess

GETPREVALIDATE() :

Prevalidate a Get object

GETPREVALIDATE(<oGet>) --> lSuccess

GETREADER() :

Execute standard READ behavior for a Get object

GETREADER(<oGet>) --> NIL

READFORMAT() :

Return, and optionally set, the format file code block

READFORMAT([<bFormat>]) --> bCurrentFormat

READKILL() :

Return, and optionally set, the READ terminate flag

READKILL([<lKillRead>]) --> lCurrentSetting

READUPDATED() :

Return, and optionally set, whether a Get changed

READUPDATED([<lChanged>]) --> lCurrentSetting

GET Class :

Class Function :

GetNew() : Create a new Get object

Exported Instance Variables :

badDate : Indicates if the editing buffer contains an invalid date
block : Code block to associate Get with a variable
buffer : Character value that defines the editing buffer
cargo : User-definable variable
changed : Indicates whether the Get:buffer has changed
clear : Indicates whether the editing buffer should be cleared
col : Get column number
colorSpec : Display attributes string
decPos : Decimal point position within the editing buffer
exitState : Means by which the user exited the Get
hasFocus : Indicates whether or not the Get object has input focus
minus : Indicates whether or not a minus sign has been entered
name : Get variable name
original : Character string containing the original value of the Get
picture : PICTURE string
pos : Current cursor position within the editing buffer
postBlock : Code block to validate a newly entered value
preBlock : Code block to decide if editing is permitted
reader : Contains a block to affect READ behavior on a Get object
rejected : Indicates if last insert/overStrike character was rejected
row : Get row number
subscript : Information about array Get objects .
type : Get variable data type
typeOut : Indicates attempt to move the cursor out of editing buffer

Exported Methods :

State Change Methods :

assign() : Assigns the editing buffer contents to the Get variable
colorDisp() : Changes a Get object’s color and then redisplay it
display() : Displays the Get on the screen .
killFocus() : Takes input focus away from the Get object
reset() : Resets the internal state information of the Get
setFocus() : Gives input focus to the Get object
undo() : Sets the Get variable back to Get:original
unTransform() : Converts character value to its original data type
updateBuffer() : Updates the editing buffer and redisplays the Get
varGet() : Returns the current value of the Get variable
varPut() : Sets the Get variable to the passed value

Cursor Movement Methods :

end() : Moves the cursor to the rightmost position
home() : Moves the cursor to the leftmost position
left() : Moves the cursor left one character
right() : Moves the cursor right one character
toDecPos() : Moves the cursor to the immediate right of Get:decPos
wordLeft() : Moves the cursor left one word
wordRight() : Moves the cursor right one word

Editing Methods :

backspace() : Moves the cursor to the left and deletes one character
delete() : Deletes the character under the cursor
delEnd() : Deletes from current cursor position to the end of the Get
delLeft() : Deletes the character to the left of the cursor
delRight() : Deletes the character to the right of the cursor
delWordLeft() : Deletes the word to the left of the cursor
delWordRight() : Deletes the word to the right of the cursor

Text Entry Methods :

insert() : Inserts characters into the editing buffer
overStrike() : Overwrites characters in the editing buffer

Menu System :

@…PROMPT :

Paint a menu item and define a message

@ <nRow>, <nCol> PROMPT <cMenuItem>
     [MESSAGE <cExpression>]

MENU TO :

Execute a lightbar menu for defined PROMPTs

     MENU TO <idVar>

          MENUMODAL :

Activate a top bar menu

         MENUMODAL(<oTopBar>, <nSelection>, <nMsgRow>,
             <nMsgLeft>, <nMsgRight>, <cMsgColor>) --> MenuID

SET MESSAGE :

Set the @…PROMPT message line row

SET MESSAGE TO [<nRow> [CENTER | CENTRE]]

SET INTENSITY :

Toggle enhanced display of GETs and PROMPTs

SET INTENSITY ON | off | <xlToggle>

SET WRAP :

Toggle wrapping of the highlights in MENUs

SET WRAP on | OFF | <xlToggle>

Browse Classes :

TBrowse :

Provides objects for browsing table-oriented data.

Description :

A TBrowse object is a general purpose browsing mechanism for table-oriented data. TBrowse objects provide a sophisticated architecture for acquiring, formatting, and displaying data. Data retrieval and file positioning are performed via user-supplied code blocks, allowing a high degree of flexibility and interaction between the browsing mechanism and the underlying data source. The format of individual data items can be precisely controlled via the TBColumn data retrieval code blocks; overall display formatting and attributes can be controlled by sending appropriate messages to the TBrowse object.

A TBrowse object relies on one or more TBColumn objects. A TBColumn object contains the information necessary to define a single column of the browse table (see TBColumn class in this chapter).

During operation, a TBrowse object retrieves data by evaluating code blocks. The data is organized into rows and columns and displayed within a specified rectangular region of the screen. The TBrowse object maintains an internal browse cursor. The data item on which the browse cursor rests is displayed in a highlighted color. (The actual screen cursor is also positioned to the first character of this data item.)

Initially, the browse cursor is placed on the data item at the top left of the browse display. Messages can then be sent to the TBrowse object to navigate the displayed data, causing the browse cursor to move. These messages are normally sent in response to user keystrokes.

New data is automatically retrieved as required by navigation requests. When navigation proceeds past the edge of the visible rectangle, rows or columns beyond that edge are automatically brought into view. When new rows are brought into view, the underlying data source is repositioned by evaluating a code block.

Note: TBrowse objects do not clear the entire window before output during redisplay operations. Part of the window may still be cleared when data from the existing display is scrolled.

Class Functions :

TBrowseNew() :

Create a new TBrowse object

 TBrowseNew(<nTop>, <nLeft>, <nBottom>, <nRight>)
 --> objTBrowse

Returns a new TBrowse object with the specified coordinate settings. The TBrowse object is created with no columns and no code blocks for data positioning. These must be provided before the TBrowse object can be used.

TBrowseDB() :

Create a new TBrowse object for browsing a database file

 TBrowseDB(<nTop>, <nLeft>, <nBottom>, <nRight>)
 --> objTBrowse

Returns a new TBrowse object with the specified coordinate settings and default code blocks for data source positioning within database files. The default code blocks execute the GO TOP, GO BOTTOM, and SKIP operations.

Note that TBrowseDB() creates an object with no column objects. To make the TBrowse object usable, you must add a column for each field to be displayed

Exported Instance Variables:

autoLite : Logical value to control highlighting
cargo : User-definable variable
colCount : Number of browse columns
colorSpec : Color table for the TBrowse display
colPos : Current cursor column position
colSep : Column separator character
footSep : Footing separator character
freeze : Number of columns to freeze
goBottomBlock : Code block executed by TBrowse:goBottom()
goTopBlock : Code block executed by TBrowse:goTop()
headSep : Heading separator character
hitBottom : Indicates the end of available data
hitTop : Indicates the beginning of available data
leftVisible : Indicates position of leftmost unfrozen column in display
nBottom : Bottom row number for the TBrowse display
nLeft : Leftmost column for the TBrowse display
nRight : Rightmost column for the TBrowse display
nTop : Top row number for the TBrowse display
rightVisible : Indicates position of rightmost unfrozen column in display
rowCount : Number of visible data rows in the TBrowse display
rowPos : Current cursor row position
skipBlock : Code block used to reposition data source
stable : Indicates if the TBrowse object is stable

Exported Methods:

Cursor Movement Methods :

down() : Moves the cursor down one row
end() : Moves the cursor to the rightmost visible data column
goBottom() : Repositions the data source to the bottom of file
goTop() : Repositions the data source to the top of file
home() : Moves the cursor to the leftmost visible data column
left() : Moves the cursor left one column
pageDown() : Repositions the data source downward
pageUp() : Repositions the data source upward
panEnd() : Moves the cursor to the rightmost data column
panHome() : Moves the cursor to the leftmost visible data column
panLeft() : Pans left without changing the cursor position
panRight() : Pans right without changing the cursor position
right() : Moves the cursor right one column
up() : Moves the cursor up one row

Miscellaneous Methods :

addColumn() : Adds a TBColumn object to the TBrowse object
colorRect() : Alters the color of a rectangular group of cells
colWidth() : Returns the display width of a particular column
configure() : Reconfigures the internal settings of the TBrowse object
deHilite() : Dehighlights the current cell
delColumn() : Delete a column object from a browse
forceStable() : Performs a full stabilization .
getColumn() : Gets a specific TBColumn object
hilite() : Highlights the current cell
insColumn() : Insert a column object in a browse
invalidate() : Forces redraw during next stabilization
refreshAll() : Causes all data to be refreshed during the next stabilize
refreshCurrent() : Causes the current row to be refreshed on next stabilize
setColumn() : Replaces one TBColumn object with another
stabilize() : Performs incremental stabilization

TBColumn :

Provides the column objects TBrowse objects.

Description :

A TBColumn object is a simple object containing the information needed to fully define one data column of a TBrowse object (see the TBrowse reference in this chapter). TBColumn objects have no methods, only exported instance variables.

Class Function :

TBColumnNew() :

Create a new TBColumn object.

TBColumnNew(<cHeading>, <bBlock>) --> objTBColumn

Exported Instance Variables :

block : Code block to retrieve data for the column
cargo : User-definable variable
colorBlock : Code block that determines color of data items
colSep : Column separator character
defColor : Array of numeric indexes into the color table
footing : Column footing
footSep : Footing separator character
heading : Column heading
headSep : Heading separator character
width : Column display width

Example :

This example is a code fragment that creates a TBrowse object and adds some TBColumn objects to it:

USE Customer NEW
//
// Create a new TBrowse object
objBrowse := TBrowseDB(1, 1, 23, 79)
//
// Create some new TBColumn objects and
// add them to the TBrowse object
objBrowse:addColumn(TBColumnNew( "Customer", ;
                    {|| Customer->Name} ))
objBrowse:addColumn(TBColumnNew( "Address", ;
                    {|| Customer->Address} ))
objBrowse:addColumn(TBColumnNew( "City", ;
                    {|| Customer->City} ))
.
. <statements to actually browse the data>
.
CLOSE Customer

For a simple and working sample look at here.