ReadVar()

Posted on January 23, 2014 by vivaclipper

READVAR()

Return variable name of current GET or MENU

Syntax

      READVAR( [<cVarName>] ) --> cOldVarName

Arguments

<cVarName> is a new variable name to set.

Returns

READVAR() return the old variable name. If no variable previously was set, READVAR() return “”.

Description

READVAR() is set inside a READ or MENU TO command to hold the uppercase name of the GET / MENU TO variable, and re-set back to old value when those commands finished. You should not normally set a variable name but rather use it to retrieve the name of a GET variable when executing a VALID or WHEN clause, or during SET KEY execution and you are inside a READ or MENU TO.

Examples

      // display a menu, press F1 to view the MENU TO variable name
      CLS
      @ 1, 10 PROMPT "blood sucking insect that infect beds   "
      @ 2, 10 PROMPT "germ; virus infection                   "
      @ 3, 10 PROMPT "defect; snag; (source of) malfunctioning"
      @ 4, 10 PROMPT "small hidden microphone                 "
      @ 6, 10 SAY "(Press F1 for a hint)"
      SET KEY 28 TO ShowVar
      MENU TO What_Is_Bug

      PROCEDURE ShowVar
         Alert( ReadVar() )     // WHAT_IS_BUG in red ALERT() box

Compliance

READVAR() works exactly like CA-Cl*pper’s READKEY().

Note however, that the <cVarName> parameter is not documented and used internally by CA-Cl*pper.

Platforms

All

Files

Library is rtl

Seealso

@…GET, @…PROMPT, MENU TO, READ, SET KEY, __AtPrompt(), __MenuTo()

Harbour UI Functions

Posted on January 23, 2014 by vivaclipper

AChoice()

Commands

Posted on January 23, 2014 by vivaclipper

User Interface

? \| ??	Display one or more values to the console
@…BOX	Draw a box on the screen
@…CLEAR	Clear a rectangular region of the screen
@…GET	Build a new Get object and display it to the screen
@…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
CLEAR TYPEAHEAD	Empty the keyboard buffer
DISPLAY	Display records to the console
INPUT*	Enter the result of an expression into a variable
KEYBOARD	Stuff a string into the keyboard buffer
LIST	List records to the console
MENU TO	Execute a lightbar menu for defined PROMPTs
READ	Activate full-screen editing mode using Get objects
RESTORE SCREEN*	Display a saved screen
SAVE SCREEN*	Save the current screen to a buffer or variable
SET BELL	Toggle sounding of the bell during full-screen operations
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 DECIMALS	Set the number of decimal places to be displayed
SET DELIMITERS	Toggle or define GET delimiters
SET ESCAPE	Toggle Esc as a READ exit key
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 INTENSITY	Toggle enhanced display of GETs and PROMPTs
SET MESSAGE	Set the @…PROMPT message line row
SET SCOREBOARD	Toggle the message display from READ or MEMOEDIT()
SET TYPEAHEAD	Set the size of the keyboard buffer
SET WRAP*	Toggle wrapping of the highlight in menus
TEXT*	Display a literal block of text
WAIT*	Suspend program processing until a key is pressed

Database

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
CONTINUE	Resume a pending LOCATE
COPY STRUCTURE	Copy the current .dbf structure to a new database (.dbf) file
COPY STRUCTURE EXTENDED	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 TAG	Delete a tag
FIND*	Search an index for a specified key value
GO	Move the pointer to the specified identity
INDEX	Build an index file
JOIN	Build new database file by merging from two work areas
LOCATE	Search sequentially for a record matching a condition
PACK	Remove deleted records from a database file
RECALL	Restore records marked for deletion
REINDEX	Rebuild open indexes in the current work area
REPLACE	Assign new values to field variables
SEEK	Search an order for a specified key value
SELECT	Change the current work area
SET AUTOPEN	Toggles automatic opening of a structural index file
SET AUTORDER	Defines the default controlling index for automatically opened index files
SET AUTOSHARE	Defines network detection for shared file access
SET DELETED	Toggle filtering of deleted records
SET DESCENDING	Change the descending flag of the controlling order
SET EXCLUSIVE*	Establish shared or exclusive USE of database files
SET FILTER	Hide records not meeting a condition
SET INDEX	Open one or more order bags in the current work area
SET MBLOCKSIZE	Change the block size for memo files
SET ORDER	Select the controlling order
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 SOFTSEEK	Toggle relative seeking
SET STRICTREAD	Toggles read optimization for database access
SET UNIQUE*	Toggle inclusion of non-unique keys into an index
SKIP	Move the record pointer to a new position
SORT	Copy to a database (.dbf) file in sorted order
SUM	Sum numeric expressions and assign results to variables
TOTAL	Summarize records by key value to a database (.dbf) 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
ZAP	Remove all records from the current database file

Program Execution

CANCEL	Terminate program processing
DO*	Executes a function or procedure
QUIT	Terminate program processing
RUN	Execute a OS command or program
SET KEY	Assign a procedure invocation to a key
NOTE*	Place a single-line comment in a program file
SET PROCEDURE*	Compile procedures and functions into the current object file

Variable Management

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
RELEASE	Delete public and private memory variables
RESTORE	Retrieve memory variables from a memory (.mem) file
SAVE	Save variables to a memory (.mem) file
STORE*	Assign a value to one or more variables
SET EXACT	Toggle exact matches for character strings

Device, Files & Folders

CLOSE	Close a specific set of files
COMMIT	Perform a solid-disk write for all active work areas
COPY FILE	Copy a file to a new file or to a device
DELETE FILE	Remove a file from disk
DIR*	Display a listing of files from a specified path
ERASE	Remove a file from disk
RENAME	Change the name of a file
SET ALTERNATE	Echo console output to a text file
SET DEFAULT	Set the application default drive and directory
SET DEVICE	Direct @…SAYs to the screen or printer
SET PATH	Specify the CA-Clipper search path for opening files
TYPE	Display the contents of a text file

Printer

EJECT	Advance the printhead to top of form
SET MARGIN	Set the page offset for all printed output
SET PRINTER	Toggle echo of output to printer or set the print destination

Label / Report

LABEL FORM	Display labels to the console
REPORT FORM	Display a report to the console

Date & Time

SET CENTURY	Modify the date format to include or omit century digits
SET DATE	Set the date format for input and display
SET EPOCH	Control the interpretation of dates with no century digits

All

What is UI ( User Interface )

Posted on October 28, 2013 by vivaclipper

The user interface (UI) , in the industrial design field of human–machine interaction, is the space where interaction between humans and machines occurs. The goal of this interaction is effective operation and control of the machine on the user’s end, and feedback from the machine, which aids the operator in making operational decisions. Examples of this broad concept of user interfaces include the interactive aspects of computer operating systems, hand tools, heavy machinery operator controls, and process controls. The design considerations applicable when creating user interfaces are related to or involve such disciplines as ergonomics and psychology.

A user interface is the system by which people (users) interact with a machine. The user interface includes hardware (physical) and software (logical) components. User interfaces exist for various systems, and provide a means of:

Input, allowing the users to manipulate a system Output, allowing the system to indicate the effects of the users’ manipulation

Generally, the goal of human-machine interaction engineering is to produce a user interface which makes it easy (self exploratory), efficient, and enjoyable (user friendly) to operate a machine in the way which produces the desired result. This generally means that the operator needs to provide minimal input to achieve the desired output, and also that the machine minimizes undesired outputs to the human.

With the increased use of personal computers and the relative decline in societal awareness of heavy machinery, the term user interface is generally assumed to mean the graphical user interface, while industrial control panel and machinery control design discussions more commonly refer to human-machine interfaces.

Other terms for user interface include human–computer interface (HCI) and man–machine interface (MMI).

Source and more info

CLI (command-line interface)

A command-line interface (CLI), also known as command-line user interface, console user interface, and character user interface (CUI), is a means of interacting with a computer program where the user (or client) issues commands to the program in the form of successive lines of text (command lines).

The CLI was the primary means of interaction with most popular operating systems in the 1970s and 1980s, including MS-DOS, CP/M, Unix, and Apple DOS. The interface is usually implemented with a command line shell, which is a program that accepts commands as text input and converts commands to appropriate operating system functions.

Command-line interfaces to computer operating systems are less widely used by casual computer users, who favor graphical user interfaces. Command-line interfaces are often preferred by more advanced computer users, as they often provide a more concise and powerful means to control a program or operating system.

Programs with command-line interfaces are generally easier to automate via scripting.

Alternatives to the command line include, but are not limited to menus, keyboard shortcuts, and various other desktop metaphors centered on the pointer (usually controlled with a mouse).

Source and more info

TUI (Text-based user interface)

Text-based user interface (TUI), also called textual user interface or terminal user interface, is a retronym that was coined sometime after the invention of graphical user interfaces, to distinguish them from user interfaces that were text-based. The concept of TUI refers primarily to the way of output and does not coincide with command-line interfaces which is a certain user input mode. An advanced TUI may, like GUIs, use the entire screen area and does not necessarily provide line-by-line output, although TUIs only use text, symbols and colors available on a given text environment.

Source and more info

GUI ( graphical user interface )

In computing, graphical user interface (GUI, is a type of user interface that allows users to interact with electronic devices through graphical icons and visual indicators such as secondary notation, as opposed to text-based interfaces, typed command labels or text navigation. GUIs were introduced in reaction to the perceived steep learning curve of command-line interfaces (CLI), which require commands to be typed on the keyboard.

The actions in GUI are usually performed through direct manipulation of the graphical elements. Besides in computers, GUIs can be found in hand-held devices such as MP3 players, portable media players, gaming devices, household appliances, office, and industry equipment. The term GUI is usually not applied to other low-resolution types of interfaces with display resolutions, such as video games (where HUD is preferred), or not restricted to flat screens, like volumetric displays because the term is restricted to the scope of two-dimensional display screens able to describe generic information.