Options and Arguments
Tk commands have got options and arguments which are strings.
set text1 [text .t] pack $text1 $text insert 1.0 "Hello World"
In Scheme, the arguments have data types as needed:
(define text1 (tk 'create-widget 'text)) (tk/pack text1) (text1 'insert '(1 . 0) "Hello World")
Scheme data are translated to Tk arguments as follows:
|
Data type |
Scheme |
Tcl/Tk |
|---|---|---|
|
false |
#f |
0 |
|
true |
#t |
1 |
|
keywords |
#:keyword |
-keyword |
|
widgets |
(tk 'create-widget 'frame) |
.frame |
|
menu commands |
#:command (lambda () ... ) |
-command {...} |
|
lists |
(item1 item2 ...) |
{item1 item2 ...} |
|
dotted pairs |
(2 . 4) |
2.4 |
|
numbers |
9 |
9 |
|
strings |
"arg" |
arg |
|
symbols |
'arg |
arg |
In some cases, you are free to use Tk-style data, e. g. 1 and 0 for #t and #f. In some other cases you must use Scheme-style data, e. g. associated commands.—My first advice is: where legibility matters, use Scheme-style data. My second advice is: legibility matters always.