CALL
Root / Documentation / [.]
Call functions by name, or run callbacks.
---
* Call by Name (Statement)
Call a function, given its name as a string, using the specified arguments. This function *must not* return a value.
** Syntax
```sb4
CALL name$, { in... }
```
|* Input | Description |
| `name$` |The name of the function to call.|
| `in...` |A list of arguments to pass to the function. Can be zero or more, depending on the function.|
** Examples
```sb4
'call GLINE by name and pass parameters
CALL "GLINE",0,0,100,100
'call a DEF by name
DEF FOO
PRINT "HELLO"
END
VAR N$="FOO"
CALL N$ '> HELLO
```
---
* Call by Name (Function Expression)
Call a function, given its name and parameters, and return its value in an expression
** Syntax
```sb4
ret = CALL(name$ {, in... })
```
|* Input | Description |
| `name$` |The name of the function to call.|
| `in...` |A list of arguments to pass to the function. Can be zero or more, depending on the function.|
|* Output | Description |
| `ret` | The return value of this function. |
** Examples
```sb4
PRINT CALL("MAX", 2,3) '> 3
```
--
* Call by Name (`OUT` Form)
Call a function given its name, in `OUT` form.
** Syntax
```sb4
CALL name$ {, in...} OUT { out... }
```
|* Input | Description |
| `name$` |The name of the function to call.|
| `in...` |A list of arguments to pass to the function. Can be zero or more, depending on the function.|
|* Output | Description |
| `out...` | The return values of this function. Can be zero or more, depending on the function. |
** Examples
```sb4
VAR YEAR,MONTH,DAY
CALL "DTREAD" OUT YEAR, MONTH, DAY
```
---
* Sprite Callback
Run all callbacks associated to sprites with `SPFUNC`, in order of sprite ID. The value of `CALLIDX` is changed to the sprite ID for each callback.
** Syntax
```sb4
CALL SPRITE
```
** Examples
```sb4
DEF MYCALL
PRINT CALLIDX()
END
SPSET 0,0
SPFUNC 0,"MYCALL"
CALL SPRITE 'prints 0
```
---
* Text Screen Callback
Run all callbacks associated to text screens with `TFUNC`, in order of text screen ID. The value of `CALLIDX` is changed to the text screen ID for each callback.
** Syntax
```sb4
CALL TEXT
```
** Examples
```sb4
DEF MYCALL
PRINT CALLIDX()
END
TFUNC 0,"MYCALL"
CALL TEXT 'prints 0
```
No posts yet (will you be the first?)