PluggableAdaptor subclass:#TypeConverter

	instanceVariableNames:''

	classVariableNames:''

	poolDictionaries:''

	category:'Interface-Support-Models'

!

!TypeConverter class methodsFor:'documentation'!

documentation

"

    a typeConverter can be used as an editFields model,

    to convert the fields string value to some object.

    No real new functionality is added here - all is inherited

    from PluggableAdapter; however, some specialized instance creation

    methods are added here..

    Notice: 

        this class was implemented using protocol information

        from alpha testers - it may not be complete or compatible to

        the corresponding ST-80 class. 

        If you encounter any incompatibilities, please forward a note 

        describing the incompatibility verbal (i.e. no code) to the ST/X team.

    [author:]

        Claus Gittinger

"

!

examples 

"

    convert a number to a string:

                                                                        [exBegin]

        |v t i|

        v := 1 asValue.

        t := HorizontalPanelView new.

        t extent:200@50.

        t horizontalLayout:#fitSpace.

        i := EditField in:t.

        i model:(TypeConverter onNumberValue:v).

        t open.

        (Delay forSeconds:3) wait.

        v value:2.

                                                                        [exEnd]

"

! !

!TypeConverter class methodsFor:'instance creation'!

onNumberValue:aValueHolder

    "create and return a typeConverter, which retrieves

     a values string representation via #value, and converts

     a number-string to a value via #value:.

     Useful as an editFields model, which operates on some

     numeric value (or aspectAdaptor, which adapts to a numeric slot)"

    ^ (self on:aValueHolder) numberToText

    "Modified: 21.2.1997 / 18:46:11 / cg"

!

onSymbolValue:aValueHolder

    "create and return a typeConverter, which retrieves

     a symbol-values string representation via #value, and converts

     a string to a symbol via #value:.

     Useful as an editFields model, which operates on some

     numeric value (or aspectAdaptor, which adapts to a numeric slot)"

    ^ (self on:aValueHolder) symbolOrNil

    "Modified: 21.2.1997 / 18:46:11 / cg"

! !

!TypeConverter methodsFor:'accessing'!

subject

    "return the cobverted subject"

    ^ model

    "Created: 21.2.1997 / 18:45:12 / cg"

!

value:newValue

    "convert and change"

    self setValue:newValue

    "Created: 21.2.1997 / 18:45:39 / cg"

! !

!TypeConverter methodsFor:'initialize-release'!

numberOrNil

    "setup the converter to convert from a string to a number

     and vice versa. Invalid numbers are converted to nil."

    self

        getBlock:[:model |

                |numericValue|

                (numericValue := model value) isNil ifTrue:[

                    String new

                ] ifFalse:[

                    numericValue printString

                ]]

        putBlock:

                [:model :string |

                |value|

                string isEmpty ifTrue:[

                    value := nil

                ] ifFalse:[

                    value := Number readFrom:string onError:nil

                ].

                model value:value]

        updateBlock: [:m :a :p | true]

    "Created: 21.2.1997 / 18:58:38 / cg"

!

numberToText

    "setup the converter to convert from a string to a number

     and vice versa, using formatString."

    self

        getBlock:[:model |

                |numericValue|

                (numericValue := model value) isNil ifTrue:[

                    String new

                ] ifFalse:[

                    numericValue printString

                ]]

        putBlock:

                [:model :string |

                |value|

                string isEmpty ifTrue:[

                    value := 0

                ] ifFalse:[

                    value := string asNumber

                ].

                model value:value]

        updateBlock: [:m :a :p | true]

    "Created: 21.2.1997 / 18:57:05 / cg"

    "Modified: 21.2.1997 / 18:59:06 / cg"

!

numberToTextFormattedBy:formatString

    "setup the converter to convert from a string to a number

     and vice versa, using formatString.

     The formatString is currently ignored when numbers are converted

     from a string."

    self

        getBlock:[:model |

                |numericValue|

                (numericValue := model value) isNil ifTrue:[

                    String new

                ] ifFalse:[

                    PrintConverter print:numericValue formattedBy:formatString

                ]]

        putBlock:

                [:model :string |

                |value|

                string isEmpty ifTrue:[

                    value := 0

                ] ifFalse:[

                    value := string asNumber "asNumberFromFormatString:formatString"

                ].

                model value:value]

        updateBlock: [:m :a :p | true]

    "Modified: 21.2.1997 / 18:59:44 / cg"

!

symbolOrNil

    "setup the converter to convert from a string to a symbol

     and vice versa. Invalid symbols (i.e. empty) are converted to nil."

    self

        getBlock:[:model |

                |symbolValue|

                (symbolValue := model value) isNil ifTrue:[

                    String new

                ] ifFalse:[

                    '#' , symbolValue asString

                ]]

        putBlock:

                [:model :string |

                |value s|

                string isEmpty ifTrue:[

                    value := nil

                ] ifFalse:[

                    s := string withoutSeparators.

                    (s startsWith:'#') ifTrue:[

                        s := s copyFrom:2

                    ].

                    value := s asSymbol

                ].

                model value:value]

        updateBlock: [:m :a :p | true]

    "Created: 21.2.1997 / 18:58:38 / cg"

! !

!TypeConverter class methodsFor:'documentation'!

version

    ^ '$Header: /cvs/stx/stx/libview2/TypeConverter.st,v 1.3 1997-02-24 19:50:19 ca Exp $'

! !