Check-in [96cdaa7bf6]

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Overview
Comment:Untabify for consistent indentation
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | trunk | minor change
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SHA3-256:96cdaa7bf66087cd6d6a0868f74445480f735ab322482a1e892a45124263be1e
User & Date: dkf 2018-05-19 10:49:14
Context
2018-05-19
10:51
Added comment to highlight a (minor) syntactic feature check-in: 3a4f7e4abc user: dkf tags: trunk
10:49
Untabify for consistent indentation check-in: 96cdaa7bf6 user: dkf tags: trunk, minor change
10:48
Added an example check-in: e6ade010a0 user: dkf tags: trunk
Changes
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Changes to tip/500.md.

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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.

# Example

    oo::class create LabelEqual {
		constructor {label} {
			set [my varname label] $label
		}
        private {
		    variable label
			method getLabel {} {
			    return $label
			}
		}
		method equals {other} {
			expr {$label eq [$other getLabel]}
		}
	}

	oo::class create Evaluated {
		superclass LabelEqual
		# Poorly chosen variable name! Happens too easily in real life
		variable label
		constructor {expression} {
			next $expression
			set label [expr $expression]
		}
	    method value {} {
			return $label
		}
	}

	set expr1 [Evaluated new {1 + 2 + 3}]
	set expr2 [Evaluated new {3 + 2 + 1}]
	puts "one is two? [$expr1 equals $expr2]"
	# Prints: one is two? 0
	puts "one=[$expr1 value] two=[$expr2 value]"
	# Prints: one=6 two=6
	puts [info vars [info object namespace $expr1]::*]
	# Prints something like: {::oo::Obj13::11 : label} ::oo::Obj13::label
	catch {$expr2 getLabel} msg
	puts $msg
	# Prints: unknown method "getLabel": must be destroy, equals or value

# Implementation

See the [`tip-500` branch](https://core.tcl.tk/tcl/timeline?r=tip-500).

# Copyright

This document has been placed in the public domain.







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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.

# Example

    oo::class create LabelEqual {
        constructor {label} {
            set [my varname label] $label
        }
        private {
            variable label
            method getLabel {} {
                return $label
            }
        }
        method equals {other} {
            expr {$label eq [$other getLabel]}
        }
    }

    oo::class create Evaluated {
        superclass LabelEqual
        # Poorly chosen variable name! Happens too easily in real life
        variable label
        constructor {expression} {
            next $expression
            set label [expr $expression]
        }
        method value {} {
            return $label
        }
    }

    set expr1 [Evaluated new {1 + 2 + 3}]
    set expr2 [Evaluated new {3 + 2 + 1}]
    puts "one is two? [$expr1 equals $expr2]"
    # Prints: one is two? 0
    puts "one=[$expr1 value] two=[$expr2 value]"
    # Prints: one=6 two=6
    puts [info vars [info object namespace $expr1]::*]
    # Prints something like: {::oo::Obj13::11 : label} ::oo::Obj13::label
    catch {$expr2 getLabel} msg
    puts $msg
    # Prints: unknown method "getLabel": must be destroy, equals or value

# Implementation

See the [`tip-500` branch](https://core.tcl.tk/tcl/timeline?r=tip-500).

# Copyright

This document has been placed in the public domain.