git-commit-vandalism/lib/class.tcl
Shawn O. Pearce 6233ab1729 git-gui: Teach class system to support [$this cmd] syntax
Its handy to be able to ask an object to do something for you by
handing it a subcommand.  For example if we want to get the value
of an object's private field the object could expose a method that
would return that value.  Application level code can then invoke
"$inst get" to perform the method call.

Tk uses this pattern for all of its widgets, so we'd certainly
like to use it for our own mega-widgets that we might develop.
Up until now we haven't needed such functionality, but I'm working
on a new revision picker mega-widget that would benefit from it.

To make this work we have to change the definition of $this to
actually be a procedure within the namespace.  By making $this a
procedure any caller that has $this can call subcommands by passing
them as the first argument to $this.  That subcommand then needs
to call the proper subroutine.

Placing the dispatch procedure into the object's variable namespace
ensures that it will always be deleted when the object is deleted.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
2007-07-08 21:12:45 -04:00

186 lines
4.2 KiB
Tcl

# git-gui simple class/object fake-alike
# Copyright (C) 2007 Shawn Pearce
proc class {class body} {
if {[namespace exists $class]} {
error "class $class already declared"
}
namespace eval $class "
variable __nextid 0
variable __sealed 0
variable __field_list {}
variable __field_array
proc cb {name args} {
upvar this this
concat \[list ${class}::\$name \$this\] \$args
}
"
namespace eval $class $body
}
proc field {name args} {
set class [uplevel {namespace current}]
variable ${class}::__sealed
variable ${class}::__field_array
switch [llength $args] {
0 { set new [list $name] }
1 { set new [list $name [lindex $args 0]] }
default { error "wrong # args: field name value?" }
}
if {$__sealed} {
error "class $class is sealed (cannot add new fields)"
}
if {[catch {set old $__field_array($name)}]} {
variable ${class}::__field_list
lappend __field_list $new
set __field_array($name) 1
} else {
error "field $name already declared"
}
}
proc constructor {name params body} {
set class [uplevel {namespace current}]
set ${class}::__sealed 1
variable ${class}::__field_list
set mbodyc {}
append mbodyc {set this } $class
append mbodyc {::__o[incr } $class {::__nextid]::__d} \;
append mbodyc {create_this } $class \;
append mbodyc {set __this [namespace qualifiers $this]} \;
if {$__field_list ne {}} {
append mbodyc {upvar #0}
foreach n $__field_list {
set n [lindex $n 0]
append mbodyc { ${__this}::} $n { } $n
regsub -all @$n\\M $body "\${__this}::$n" body
}
append mbodyc \;
foreach n $__field_list {
if {[llength $n] == 2} {
append mbodyc \
{set } [lindex $n 0] { } [list [lindex $n 1]] \;
}
}
}
append mbodyc $body
namespace eval $class [list proc $name $params $mbodyc]
}
proc method {name params body {deleted {}} {del_body {}}} {
set class [uplevel {namespace current}]
set ${class}::__sealed 1
variable ${class}::__field_list
set params [linsert $params 0 this]
set mbodyc {}
append mbodyc {set __this [namespace qualifiers $this]} \;
switch $deleted {
{} {}
ifdeleted {
append mbodyc {if {![namespace exists $__this]} }
append mbodyc \{ $del_body \; return \} \;
}
default {
error "wrong # args: method name args body (ifdeleted body)?"
}
}
set decl {}
foreach n $__field_list {
set n [lindex $n 0]
if {[regexp -- $n\\M $body]} {
if { [regexp -all -- $n\\M $body] == 1
&& [regexp -all -- \\\$$n\\M $body] == 1
&& [regexp -all -- \\\$$n\\( $body] == 0} {
regsub -all \
\\\$$n\\M $body \
"\[set \${__this}::$n\]" body
} else {
append decl { ${__this}::} $n { } $n
regsub -all @$n\\M $body "\${__this}::$n" body
}
}
}
if {$decl ne {}} {
append mbodyc {upvar #0} $decl \;
}
append mbodyc $body
namespace eval $class [list proc $name $params $mbodyc]
}
proc create_this {class} {
upvar this this
namespace eval [namespace qualifiers $this] [list proc \
[namespace tail $this] \
[list name args] \
"eval \[list ${class}::\$name $this\] \$args" \
]
}
proc delete_this {{t {}}} {
if {$t eq {}} {
upvar this this
set t $this
}
set t [namespace qualifiers $t]
if {[namespace exists $t]} {namespace delete $t}
}
proc make_toplevel {t w args} {
upvar $t top $w pfx this this
if {[llength $args] % 2} {
error "make_toplevel topvar winvar {options}"
}
set autodelete 1
foreach {name value} $args {
switch -exact -- $name {
-autodelete {set autodelete $value}
default {error "unsupported option $name"}
}
}
if {[winfo ismapped .]} {
regsub -all {::} $this {__} w
set top .$w
set pfx $top
toplevel $top
} else {
set top .
set pfx {}
}
if {$autodelete} {
wm protocol $top WM_DELETE_WINDOW "
[list delete_this $this]
[list destroy $top]
"
}
}
## auto_mkindex support for class/constructor/method
##
auto_mkindex_parser::command class {name body} {
variable parser
variable contextStack
set contextStack [linsert $contextStack 0 $name]
$parser eval [list _%@namespace eval $name] $body
set contextStack [lrange $contextStack 1 end]
}
auto_mkindex_parser::command constructor {name args} {
variable index
variable scriptFile
append index [list set auto_index([fullname $name])] \
[format { [list source [file join $dir %s]]} \
[file split $scriptFile]] "\n"
}