Danny A. del Pilar

Contributed works of Danny A. del Pilar

Browse Test Demo

Easter Sunday Calculation

Generate Gregorian Calendar

HMG source code converter

How to build menu like old ACHOICE function?

KPI (Key Performance Indicator) Dashboard

Return value from modal window (Record Picker) 

Similar SCATTER / GATHER en HMG

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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

C5 Memory Management

Clipper Memory Management

Once upon a time ..

PCs has a 640 KB memory limit and Clipper programmers was must struggled with errors such as Memory overflow, Conventional memory exhausted, Stack overflow and so on…

This article mainly focused on this subject.

In our modern era we haven’t such problems, because we have gigabytes of memory installed in our computers. Morever OS’s offers to us immense memory management possibilities transparent to us. Like we have unlimited memory to use.

But nothing can be unlimited …

This article of Roger Donnay has very useful info about efficient ways to using memory; and especially variable handling.

Word wrap in EditBox

EDITBOX control doesn’t have a WORD-WRAP property but has this feature via HSCROLLBAR property.

Look at the sample :

/*
*  HMG – Harbour Win32 GUI library Demo
*
*  Copyright 2010 Roberto Lopez
*
HMG official EDITBOX demo slightly modified to demonstrate effect of HSCROLLBAR property.

*/

#include "hmg.ch"
Function Main
   LOCAL cTestText := STRTRAN( TestText(), CRLF, '' ) 

   DEFINE WINDOW Form_1 ;
      AT 0,0 ;
      WIDTH 640 HEIGHT 480 ;
      TITLE 'HMG EditBox!! Demo' ;
      MAIN 

      ON KEY ESCAPE ACTION Form_1.Release
      DEFINE STATUSBAR
         STATUSITEM 'HMG Power Ready!' 
      END STATUSBAR
      @ 30,10 EDITBOX Edit_1 ;
        WIDTH 600 ;
        HEIGHT 170 ;
        VALUE cTestText ;
        TOOLTIP 'EDITBOX with HSCROLLBAR is .T.'
      @ 230,10 EDITBOX Edit_2 ;
        WIDTH 600 ;
        HEIGHT 170 ;
        VALUE cTestText ;
        TOOLTIP 'EDITBOX with HSCROLLBAR is .F.' ;
        NOHSCROLL
  END WINDOW
  Form_1.Center()
  Form_1.Activate()

Return Nil
FUNCTION TestText()
    RETURN "HMG 2.0 ALPHA BUILD 004 Changelog: "+;
           "- New: Cell ( nRow , nCol ) property for GRID control (read(write). "+;
           "- New: Edit routines for GRID control. Editing is now 'in-cell'. "+;
           "- New: 'DynamicForeColor' / 'DynamicBackColor' properties for GRID "+;
           "control. Codeblock array (one element per column) evaluated "+;
           "for each cell at any grid change. "+;
           "This.CellRowIndex, This.CellColIndex and This.CellValue variables are "+;
           "available at codeblock evaluation. "+;
           "Sample: "+;
           "bColor := { || if ( This.CellRowIndex/2 == int(This.CellRowIndex/2) , ; "+;
           "RGB (128,128,128) , RGB (192,192,192) ) } "+;
           "DYNAMICBACKCOLOR { bColor , bColor, bColor, bColor, bColor, bColor } "+;
           "See \hmg\samples\grid\grid_10 "+;
           "\hmg\samples\grid\grid_11 "+;
           "\hmg\samples\grid\grid_12 "

Basic Controls – 3

( Status Bar, Check Box )

We are continuing with Viva_HMG.hbp, Main.prg and Main.fmg.

While using a table and while navigating between its records, we need some extra info to show to user: Name of table, current record and record count in the table. So user always feels comfortable by knowing where is he / she; which table, which record?

The status bar control is convenient for this purpose and though this is a quite simple control, IDE has a builder for it: Status bar builder.

When you choose this builder ( after open the .fmg file by IDE of course ), a dialog box will open:

By using this dialog box we can define a status bar. We can prefer define status bar manually too:

    DEFINE STATUSBAR FONT "Tahoma" SIZE 9
        STATUSITEM "" WIDTH 300
        STATUSITEM "" WIDTH 40
        DATE         WIDTH 90
        CLOCK             WIDTH 90
    END STATUSBAR

After define status bar, we need assign values to its items. We don’t need assign values to DATE and CLOCK items, because these items will be updated by system (HMG) automatically.

First a little procedure :

PROCEDURE InitEdit()

EditReco.StatusBar.Item( 1 ) := cTableFNam

ReadData()

RETURN // InitEdit()

Change ON INIT event of  EditReco form from ReadData() to InitEdit(.

And add this line at end of ReadData() procedure.

 EditReco.StatusBar.Item( 2 ) := LTRIM( STR( RECN() ) ) + "\" + ;
                                 LTRIM( STR( LASTREC() ) )

Let’s look at the result :

Whenever active record change, Item( 2 ) of Status Bar will be updated ( 5/25 ) in above picture.

In this step, user must use “Save” button every time current record edited.  Whereas “Read” process is different; whenever current record changed, values of text boxes automatically updated. What about automatic save? May be, we can do this; but user may don’t want such automation. Asking a question like “Do you want save?” every change doesn’t a good way.

The better way may be: put a control to form such “Auto save” with On / Off option.

Yes, fortunately we have such control: Check Box.

We can replace a Check Box control to EditReco form with chbAutoSave name and Auto Save caption:

Now, how we will implement Auto Save process?.

By adding a little IF clause to ACTION events of navigation buttons:

Top : (IF(EditReco. chbAutoSave.Value , SaveData(), ), DBGOTOP(), ReadData() )

Next : (IF(EditReco. chbAutoSave.Value , SaveData(), ), DBSKIP(), ReadData() )

Previous : ( IF(EditReco. chbAutoSave.Value , SaveData(), ), DBSKIP( -1 ), ReadData() )

Last : (IF(EditReco. chbAutoSave.Value , SaveData(), ), DBGOBOTTOM(), ReadData() )

To be continued …

Download source files

Mini Agenda

This is a mini application developed primarily to denote some wonderful features of HMG.

Mini Agenda uses:

– A text (csv)  file for data source and Grid as browse of this file

– DEFINE ACTIVEX for “About” page from a .html file

– HFCL library ( Thanks to S. Rathinagiri for GridPrint )

Features :

– File operations: New, Open, ReOpen, Close, Save, Save as, Print

– Record operations:  Append, Delete, Insert

– Three way ( Natural, Ascending, Descending) sorting columns

– Preserve current item after sort

– In_place editing

– Incremental (and “soft” ) Search

– .ini File for keeping record of last used data file

Download : source, executable.