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