ReadVar()

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()

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Commands

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 )

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).

Human-MachineInterface

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

commandLine

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

QB45TUInterface

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.

FedoraGUInterface

Source and more info

Clipper 5.x RG Summary

About This Summary

Functions

Commands

Classes

Statements

Operators

Tables

Terms

         Categories: 

Variable Handling

Data Manipulation

Flow Control

User Interface

General

Basics

Global Settings

Advanced

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TBrowse Classes

Environment

Database Commands and Statements

Database Functions

RDD Functions

Index Commands and Functions

File Management

Printing

Networking

Pre-processor Directives

Debugging and Error Handling

User Interface Terms

Background Color :

The color that appears behind displayed text of another color (the foreground color).

See Also: Foreground Color

Column :

A numeric value that represents a position on the display screen or on the printed page.

Console Input/Output :

A style of operation of the keyboard and display that emulates a simple typewriter-like interface. Console input echoes each key typed and provides processing for the backspace and return keys. Console output wraps to the next line when the output reaches the right edge of the visible display, and scrolls the display when the output reaches the bottom of the visible display.

See Also: Full-screen Input/Output

Cursor :

An onscreen indicator used to show the current keyboard input focus and is displayed as a block or underline character. The cursor moves in response to characters or control keys typed by the user.

Enhanced Color :

The color used to display GETs or PROMPTs (if INTENSITY is ON).

See Also: Standard Color

Foreground Color :

The color of text appearing on the screen, usually on a different colored background.

See Also: Background Color

Full-screen Input/Output :

A style of operation of the keyboard and display used for complex data entry and display tasks. Full-screen input and output are generally performed using the @..SAY, @..GET and READ commands. Full-screen output is distinguished from console-style output by the fact that control characters (e.g., backspace, carriage return) are not processed, and wrapping and scrolling do not occur at the boundaries of the visible display area.

See Also: Console Input/Output

Highlight :

Indicates input focus for menus, browsers, or GETs. With menus and browsers, the currently selected item or cell has input focus and is displayed in the current enhanced color or inverse video. With GETs, the current GET is highlighted in the current enhanced color or inverse video while the other GETs are displayed in the current standard color if an unselected color setting is active.

See Also: Cell, Enhanced Color, Input Focus, Standard Color

Input Focus :

The GET, browse cell, or menu item where user interaction can take place is said to have input focus. The item with input focus usually is displayed in enhanced color or inverse video.

Insert Mode :

A data entry mode entered when the user presses the insert key. When this mode is active, characters are inserted at the cursor position. Text to the right of the cursor is shifted right.

See Also: Overstrike Mode

Keyboard Buffer :

An area of memory dedicated to storing input from the keyboard while a program is unable to process the input. When the program is able to accept the input, the keyboard buffer is emptied.

Menu :

An onscreen list of choices from which the user selects. Menus range from simple to elaborate forms. Two examples are menus that pull down from the top of the screen (an elaborate type requiring more programming), or a simple list of numbered items from which the user selects by entering the appropriate number.

Overstrike Mode :

A data entry mode entered when the user presses the insert key. When this mode is active, characters are entered at the cursor position and text to the right of the cursor remains stationary.

Picture :

A string that defines the format for data entry or display in a GET, SAY, or the return value of TRANSFORM(). Picture strings are comprised of functions which affect the formatting as a whole and a series of template characters that affect formatting on a character by character basis.

See Also: Template

Prompt :

A series of characters displayed on the screen indicating that input from the keyboard is expected.

Relative Addressing :

To refer to a memory address, array element, screen location, or printer location with respect to another value, rather than referring to a specific address or element.

Row :

A numeric expression that evaluates to an integer identifying a screen or printer row position.

See Also: Column, Field, Record

Scoreboard :

An area of the display on line 0 beginning at column 60 that displays status information during certain data entry operations.

Scrolling :

The action that takes place when the user attempts to move the cursor or highlight beyond the window boundary to access information not currently displayed.

See Also: Window

Standard Color :

The color pair definition that is used by all output options (such as SAY and ?), with the exception of GETs and PROMPTs, that use the enhanced color pair.

See Also : Enhanced Color

Template :

A mask that specifies the format in which data should be displayed. For example, you might want to store phone numbers as “9999999999” to save space, but use a template to display the number to the user as “(999) 999-9999.”

Typeahead Buffer :

See : Keyboard Buffer

Unselected Color :

The color pair definition used to display all but the current GET or the GET that has input focus. If this color setting is specified, the current GET is displayed using the current enhanced color.

See Also: Enhanced Color

User Function :

A user-defined function called by ACHOICE(), DBEDIT(), or MEMOEDIT() to handle key exceptions. A user function is supplied to one of these functions by passing a parameter consisting of a string containing the function’s name.

User Interface :

The way a program interacts with its user (i.e., menu operation and selection, data input methods, etc.)

Wait State :

A wait state is any mode that extracts keys from the keyboard except for INKEY(). These modes include ACHOICE(), DBEDIT(), MEMOEDIT(), ACCEPT, INPUT, READ and WAIT.

Window :

A rectangular screen region used for display. A window may be the same size or smaller than the physical screen. Attempting to display information that extends beyond the specified boundaries of the window clips the output at the window edge.

Word Wrapping :

The process of continuing the current text on the next line of a display when a boundary is reached and breaking the text on a word boundary.