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markom |
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As much as possible, I've tried to make itcl3.0 backward-compatible
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with earlier releases. The class definition syntax has not changed
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at all from itcl2.2, and the old itcl1.x syntax is still supported.
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But you'll notice changes related to namespaces. John Ousterhout
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adopted a slightly different namespace model for Tcl8. The syntax
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of the "namespace" command is different, as well as the semantics
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for command/variable lookups and imports. Also, John Ousterhout
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failed to adopt ensembles into the Tcl core, so itcl can't add
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functions like "info objects" and "info classes" into the usual "info"
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command. These functions have been moved to a new "itcl::find" command.
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The [incr Widgets] package has changed quite a bit. There are many
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new widgets, and some of the existing widgets were streamlined--some
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of the widget options were removed to improve performance. For details,
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see the "CHANGES" file in the iwidgets3.0.0 directory. Because there
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are a lot of changes, this distribution contains the iwidgets2.2.0
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package, which is backward-compatible with the existing [incr Widgets].
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Following is a quick summary of changes, to serve as a porting guide.
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----------------------------------|-------------------------------------
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You have code like this... | change to this...
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----------------------------------|-------------------------------------
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namespace foo {...} | namespace eval foo {...}
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delete namespace foo | namespace delete foo
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info which -namespace $name | if {![string match ::* $name]} {
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| set name [namespace current]::$name
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| }
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info context | namespace current
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info objects ... | itcl::find objects ...
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info classes ... | itcl::find classes ...
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In itcl2.2, commands/classes | In Tcl8.0, all commands/classes that
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could be found in any namespace | are not in the global namespace must
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in a hierarchy. So within a | be qualified. For example, the
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namespace like "iwidgets" you | "iwidgets" namespace has a bunch of
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could use simple names like: | classes within it. You must always
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| refer to these classes with qualified
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| names, like this:
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Labeledwidget::alignlabels ... | iwidgets::Labeledwidget::alignlabels ...
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Pane #auto | iwidgets::Pane #auto
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In itcl2.2, the "global" | In Tcl8.0, the "variable" command is
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command was used to access | used to access variables in a namespace:
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variables in a namespace: |
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namespace foo { | namespace eval foo {
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variable x 0 | variable x 0
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proc example {} { | proc example {} {
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global x | variable x
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return $x | return $x
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} | }
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} | }
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public itk_component add... | itk_component add ...
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protected itk_component add... | itk_component add -protected ...
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private itk_component add... | itk_component add -private ...
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OTHER DIFFERENCES
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------------------------------------------------------------------------
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- You can now use instance variables (along with the usual common
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variables) with the "scope" command. Thus, you're no longer forced
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to use the trick with a common array like: [scope modes($this)]
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- All widget/mega-widget access commands (e.g., ".foo.bar") are
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installed in the global namespace. Therefore, they can be accessed
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from any namespace context.
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- The [incr Widgets] package used to be loaded by default. You must
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now use the "package require" command to load it explicitly:
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package require Iwidgets <-- loads the lastest (iwidgets3.0.0)
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package require -exact Iwidgets 2.2 <-- loads the older release
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- Command/variable names are now reported with fully-qualified names
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in "info" inquiries and in error messages.
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- No public/protected/private declarations outside of class definitions
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- The "scope" command used to be more or less the same as the "code"
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command. In itcl3.x, "scope" is only for variables, and if a variable
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is not recognized, you'll get an error.
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- The "code" command used to return a value like "@scope ...". It now
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returns "namespace inscope ...", to be compatible with Tcl8.
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- The prototypes for Itcl_RegisterC and Itcl_FindC have changed. You
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can now include ClientData when you register C functions. Also, there
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is a new Itcl_RegisterObjC function for (objc,objv)-style command
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handlers.
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