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Overview
| Comment: | Add some titles to the examples |
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| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | trunk |
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8b7522e1b5f7f83e9b58d973113f9a56 |
| User & Date: | dkf 2018-05-27 10:35:37.367 |
Context
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2018-05-27
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| 10:43 | A few more notes on exporting, and lengthen some very short paragraphs by combining them. check-in: a023e48805 user: dkf tags: trunk | |
| 10:35 | Add some titles to the examples check-in: 8b7522e1b5 user: dkf tags: trunk | |
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2018-05-26
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| 09:49 | Fixed typo in JO's name (SHAME!) check-in: 22823b2821 user: fbonnet tags: trunk | |
Changes
Changes to tip/500.md.
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A supporting introspector is also added, **info object creationid**, which
returns the creation ID of any existing object. It also applies to classes.
Again, note that creation IDs are _always_ system-allocated and are _never_
guaranteed to be unique between interpreters, either in multiple processes or
in the same thread or process; they are only ever locally unique.
# Examples
This example shows a private variable linked to a Tk entry:
oo::class create Editable {
variable w; # Allow subclasses to see this
private variable val; # Hide this from subclasses
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A supporting introspector is also added, **info object creationid**, which
returns the creation ID of any existing object. It also applies to classes.
Again, note that creation IDs are _always_ system-allocated and are _never_
guaranteed to be unique between interpreters, either in multiple processes or
in the same thread or process; they are only ever locally unique.
# Examples
## Example: Private Variables and Tk
This example shows a private variable linked to a Tk entry:
oo::class create Editable {
variable w; # Allow subclasses to see this
private variable val; # Hide this from subclasses
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340 341 342 343 344 345 346 347 348 349 350 351 352 353 |
}
Editable create field .e
field trace {args {
puts "field is now [field value]"
}}
field value "Set the contents"
Ths is an example of private methods. It shows how private methods can be used
to manage the complexity of a method without making its API (as exposed to
either subclasses or the rest of Tcl) overly complex.
oo::class create Modulator {
# The exported interface to the class
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}
Editable create field .e
field trace {args {
puts "field is now [field value]"
}}
field value "Set the contents"
## Example: Private Methods and Code Complexity Management
Ths is an example of private methods. It shows how private methods can be used
to manage the complexity of a method without making its API (as exposed to
either subclasses or the rest of Tcl) overly complex.
oo::class create Modulator {
# The exported interface to the class
|
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390 391 392 393 394 395 396 397 398 399 400 401 402 403 |
# invoked from within
# "::oo::Obj15 modulate 5 6 7 8"
catch {$m no.such.method} msg
puts $msg
# Prints something like:
# unknown method "no.such.method": must be destroy or modulate
This is a combined example of private methods and variables.
oo::class create LabelEqual {
constructor {label} {
set [my varname label] $label
}
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# invoked from within
# "::oo::Obj15 modulate 5 6 7 8"
catch {$m no.such.method} msg
puts $msg
# Prints something like:
# unknown method "no.such.method": must be destroy or modulate
## Example: Private Methods and Variables Working Together
This is a combined example of private methods and variables.
oo::class create LabelEqual {
constructor {label} {
set [my varname label] $label
}
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puts "one=[$expr1 value] two=[$expr2 value]"
# Prints:
# one=6 two=6
puts [info vars [info object namespace $expr1]::*]
# Prints something like:
# {::oo::Obj13::11 : label} ::oo::Obj13::label
This example highlights the behaviour of private variables and
`info object creationid`:
# A simple introspection procedure for classes
proc dumpinfo cls {
puts "class ID of $cls is [info object creationid $cls]"
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puts "one=[$expr1 value] two=[$expr2 value]"
# Prints:
# one=6 two=6
puts [info vars [info object namespace $expr1]::*]
# Prints something like:
# {::oo::Obj13::11 : label} ::oo::Obj13::label
## Example: Private Variable Naming and Creation IDs
This example highlights the behaviour of private variables and
`info object creationid`:
# A simple introspection procedure for classes
proc dumpinfo cls {
puts "class ID of $cls is [info object creationid $cls]"
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