Practical Programming in Tcl & Tk, Third Edition By Brent B. Welch
Table of Contents
Chapter 43. A User Interface to Bindings
All that remains is the actual change or definition of a binding and some way to remember the bindings the next time the application is run. The BindDefine procedure attempts a bind command that uses the contents of the entries. If it succeeds, then the edit window is removed by unpacking it.
The bindings are saved by Bind_Save as a series of Tcl commands that define the bindings. It is crucial that the list command be used to construct the commands properly.
Bind_Read uses the source command to read the saved commands. The application must call Bind_Read as part of its initialization to get the customized bindings for the widget or class. It also must provide a way to invoke Bind_Interface, such as a button, menu entry, or key binding.
Example 43-7 Defining and saving bindings.
proc BindDefine { f } { if [catch { bind [$f.top.e get] [$f.edit.key.e get] \ [$f.edit.cmd.e get] } err] { Status $err } else { # Remove the edit window pack forget $f.edit } } proc Bind_Save { dotfile args } { set out [open $dotfile.new w] foreach w $args { foreach seq [bind $w] { # Output a Tcl command puts $out [list bind $w $seq [bind $w $seq]] } } close $out file rename -force $dotfile.new $dotfile } proc Bind_Read { dotfile } { if [catch { if [file exists $dotfile] { # Read the saved Tcl commands source $dotfile } } err] { Status "Bind_Read $dotfile failed: $err" } }
