@ Function
Sets the cursor to a specified position on the terminal and generates video effects characters.
Syntax
@(column {,row })
@(code)
Syntax Elements
column is the column position on the current line to set the cursor to.
row is the line number on which to position the cursor. The default is the current line.
code generates an extended cursor addressing code or a video effects code.
Comments
The @ function, used with the PRINT and CRT statements, sets the cursor to a specified position on the terminal. The @ function can also be used to generate video effects on specified characters. These effects include bolding, dimming, underlining, blanking, flashing and reverse video (see video effects codes).
Operation
Values of the expressions must be within the row and column limits defined by page width and depth set by the most recent execution of the TERM command.
The left-most column is numbered column 0: the top line is numbered line 0. Therefore, if the terminal screen is 80 columns wide, the columns are numbered 0 to 79.
The @ function cannot be used to format spooled printer output.
The @ function can appear anywhere that a legal expression is allowed, including assignment statements. For example:
@DIALOG = START = @(10,1) . . PRINT START:"text..."
If a Matrix printer is being used, the matrix parameter must be set to 1 using the TERM command. Rows and columns start at zero on the terminal and one on the Matrix printer.
Extended Cursor Addressing
To provide a consistent way of emitting terminal-independent character strings (such as clear to EOL), DataBasic supports an extended cursor addressing process. The @ function allows a single, negative parameter that returns the correct cursor control string for the terminal defined by TERMTYPE. The returned string is based on the following parameters:
| Code | Operation |
|---|---|
| -1 | Clear screen sequence including the number of pad characters specified in the FF delay field of the TERM settings. |
| -2 | Cursor-home sequence. |
| -3 | Clear-to-end-of-screen sequence. |
| -4 | Clear-to-end-of-line sequence. |
| -5 | Start flashing. |
| -6 | Stop flashing. |
| -7 | Start protect. |
| -8 | Stop protect. |
| -9 | Cursor-back sequence. |
| -10 | Cursor-up sequence. |
| -11 | Cursor on. |
| -12 | Cursor off. |
| -13 | Status line on. |
| -14 | Status line off. |
| -15 | Cursor forward. |
| -16 | Cursor down. |
| -17 | Enable slave port. |
| -18 | Disable slave port. |
| -19 | Screen dump. |
Different terminal types are specified via the TERM or SSM command (refer to Terminal Types).
Video Effects
The table below lists the video effects that can be achieved using the @ function. These codes send an eight-bit character to the terminal.
The video effects can also be achieved by using the code (without the minus sign) as the value in a CHAR() function. PRINT CHAR(130) is the same as PRINT @(-130). The same is not true for extended cursor addressing codes.
All of the video effects shown in the table may not work with all terminals. For example, one terminal may not provide for Dimmed and Blanked Video while another will not provide for Bold Video. Consult the appropriate terminal documentation for complete information.
| Code | Bold | Underlined | Blanked | Reversed | Flashing | Dimmed | Code |
|---|---|---|---|---|---|---|---|
| -128 | This is video off. | -128 | |||||
| -129 | Dimmed | -129 | |||||
| -130 | Flashing | -130 | |||||
| -131 | Flashing | Dimmed | -131 | ||||
| -132 | Reversed | -132 | |||||
| -133 | Reversed | Dimmed | -133 | ||||
| -134 | Reversed | Flashing | -134 | ||||
| -135 | Reversed | Flashing | Dimmed | -135 | |||
| -136 | Blanked | -136 | |||||
| -137 | Blanked | Dimmed | -137 | ||||
| -138 | Blanked | Flashing | -138 | ||||
| -139 | Blanked | Flashing | Dimmed | -139 | |||
| -140 | Blanked | Reversed | -140 | ||||
| -141 | Blanked | Reversed | Dimmed | -141 | |||
| -142 | Blanked | Reversed | Flashing | -142 | |||
| -143 | Blanked | Reversed | Flashing | Dimmed | -143 | ||
| -144 | Underlined | -144 | |||||
| -145 | Underlined | Dimmed | -145 | ||||
| -146 | Underlined | Flashing | -146 | ||||
| -147 | Underlined | Flashing | Dimmed | -147 | |||
| -148 | Underlined | Reversed | -148 | ||||
| -149 | Underlined | Reversed | Dimmed | -149 | |||
| -150 | Underlined | Reversed | Flashing | -150 | |||
| -151 | Underlined | Reversed | Flashing | Dimmed | -151 | ||
| -152 | Underlined | Blanked | -152 | ||||
| -153 | Underlined | Blanked | Dimmed | -153 | |||
| -154 | Underlined | Blanked | Flashing | -154 | |||
| -155 | Underlined | Blanked | Flashing | Dimmed | -155 | ||
| -156 | Underlined | Blanked | Reversed | -156 | |||
| -157 | Underlined | Blanked | Reversed | Dimmed | -157 | ||
| -158 | Underlined | Blanked | Reversed | Flashing | -158 | ||
| -159 | Underlined | Blanked | Reversed | Flashing | Dimmed | -159 | |
| -160 | Bold | -160 | |||||
| -161 | Bold | Dimmed | -161 | ||||
| -162 | Bold | Flashing | -162 | ||||
| -163 | Bold | Flashing | Dimmed | -163 | |||
| -164 | Bold | Reversed | -164 | ||||
| -165 | Bold | Reversed | Dimmed | -165 | |||
| -166 | Bold | Reversed | Flashing | -166 | |||
| -167 | Bold | Reversed | Flashing | Dimmed | -167 | ||
| -168 | Bold | Blanked | -168 | ||||
| -169 | Bold | Blanked | Dimmed | -169 | |||
| -170 | Bold | Blanked | Flashing | -170 | |||
| -171 | Bold | Blanked | Flashing | Dimmed | -171 | ||
| -172 | Bold | Blanked | Reversed | -172 | |||
| -173 | Bold | Blanked | Reversed | Dimmed | -173 | ||
| -174 | Bold | Blanked | Reversed | Flashing | -174 | ||
| -175 | Bold | Blanked | Reversed | Flashing | Dimmed | -175 | |
| -176 | Bold | Underlined | -176 | ||||
| -177 | Bold | Underlined | Dimmed | -177 | |||
| -178 | Bold | Underlined | Flashing | -178 | |||
| -179 | Bold | Underlined | Flashing | Dimmed | -179 | ||
| -180 | Bold | Underlined | Reversed | -180 | |||
| -181 | Bold | Underlined | Reversed | Dimmed | -181 | ||
| -182 | Bold | Underlined | Reversed | Flashing | -182 | ||
| -183 | Bold | Underlined | Reversed | Flashing | Dimmed | -183 | |
| -184 | Bold | Underlined | Blanked | -184 | |||
| -185 | Bold | Underlined | Blanked | Dimmed | -185 | ||
| -186 | Bold | Underlined | Blanked | Flashing | -186 | ||
| -187 | Bold | Underlined | Blanked | Flashing | Dimmed | -187 | |
| -189 | Bold | Underlined | Blanked | Reversed | Dimmed | -189 | |
| -190 | Bold | Underlined | Blanked | Reversed | Flashing | -190 | |
| -191 | Bold | Underlined | Blanked | Reversed | Flashing | Dimmed | -191 |
MultiValue Compatibility
Refer to MultiValue Compatibility.
Example 1
This example clears the screen and prints the heading "MAIN MENU" at the top of screen starting at the 35th column.
HEAD = @(35,0):"MAIN MENU":@(35,1) PRINT @(-1),HEAD
Example 2
This example clears the screen and prints a bold and flashing "MAIN MENU" at the top of the screen:
HEAD = "MAIN MENU" PRINT @(-1):@(-162),HEAD:@(-128)