"

 COPYRIGHT (c) 1995 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

Object subclass:#PrintConverter 

	 instanceVariableNames:'valueToStringBlock stringToValueBlock'

	 classVariableNames:''

	 poolDictionaries:''

	 category:'Interface-Support'

!

!PrintConverter class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1995 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

!

version 

"

"

!

documentation

"

    printConverters are used with editFields to convert an object

    to/from some printed representation.

    Conversion is done via two blocks which can be set at instance

    creation time - either as custom blocks ot to one of the

    standard conversions.

    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 to the ST/X team.

"

!

examples 

"

      |conv|

      conv := (PrintConverter new)

		  toPrint:[:date | date printString]

		  toRead:[:string | Date readFromString:string].

      (conv printStringFor:(Date today)) inspect.

      (conv readValueFrom:(Date today printString)) inspect

      |conv|

      conv := (PrintConverter new) initForNumber.

      (conv printStringFor:12345) inspect.

      (conv readValueFrom:'12345') inspect

      |conv|

      conv := (PrintConverter new) initForYesNo.

      (conv printStringFor:true).  

      (conv printStringFor:false).    

      (conv readValueFrom:'yes').  

      (conv readValueFrom:'no').  

      'if language is german:'.

      (conv readValueFrom:'ja').    

      (conv readValueFrom:'nein')  

    concrete example: convert in an inputField:

      |dialog field|

      dialog := Dialog new.

      dialog addTextLabel:'a number (and only numbers):'.

      dialog addVerticalSpace.

      field := dialog addInputFieldOn:(0 asValue).

      field converter:(PrintConverter new initForNumber).

      field immediateAccept:true.

      dialog addOkButton.

      dialog open.

      dialog accepted ifTrue:[

	  Transcript showCr:field editValue

      ]

    see more examples in the EditField examples.

"

! !

!PrintConverter class methodsFor:'instance creation'!

new

    ^ (super new) 

	toPrint:[:val | val]

	toRead:[:string | string]

! !

!PrintConverter methodsFor:'initialization'!

toPrint:printBlock toRead:readBlock

    "initialize to convert using two custom blocks"

    valueToStringBlock := printBlock.

    stringToValueBlock := readBlock.

!

initForInteger

    "initialize to convert to/from an integer 

     - if the string is empty or invalid, convert to 0"

    valueToStringBlock := [:num | num printString].

    stringToValueBlock := [:string | Integer readFromString:string onError:0]

!

initForIntegerOrNil

    "initialize to convert to/from an integer 

     - if the string is empty or invalid, convert to nil"

    valueToStringBlock := [:num | 

	num isNil ifTrue:[''] 

		  ifFalse:[num printString]].

    stringToValueBlock := [:string | 

	Integer readFromString:string onError:nil]

!

initForNumber

    "initialize to convert to/from a number 

     - if the string is empty or invalid, convert to 0"

    valueToStringBlock := [:num | num printString].

    stringToValueBlock := [:string | Number readFromString:string onError:0]

!

initForNumberOrNil

    "initialize to convert to/from a number 

     - if the string is empty or invalid, convert to nil"

    valueToStringBlock := [:num | 

	num isNil ifTrue:[''] 

		  ifFalse:[num printString]].

    stringToValueBlock := [:string | 

	Number readFromString:string onError:nil]

!

initForString

    "initialize for a string - this is trivial"

    valueToStringBlock := [:val | val isNil ifTrue:[''] ifFalse:[val]].

    stringToValueBlock := [:string | string]

!

initForDate

    "initialize to convert to/from a date 

     - if the string is empty or invalid, convert to the current date"

    valueToStringBlock := [:date | date printString].

    stringToValueBlock := [:string | Date readFromString:string onError:[Date today]]

!

initForDateOrNil

    "initialize to convert to/from a date 

     - if the string is empty or invalid, convert to nil"

    valueToStringBlock := [:date | date printString].

    stringToValueBlock := [:string | Date readFromString:string onError:nil]

!

initForYesNo

    "initialize to convert a 'yes'/'no' string to/from a boolean 

     The string is supposed to be in the current Language

     (i.e. if german, ja/nein has to be enterred.

     Invalid entries are converted to false."

    valueToStringBlock := [:bool | bool ifTrue:[ApplicationModel classResources string:'yes']

					ifFalse:[ApplicationModel classResources string:'no']].

    stringToValueBlock := [:string | string = (ApplicationModel classResources string:'yes')]

! !

!PrintConverter methodsFor:'converting'!

printStringFor:aValue

    ^ valueToStringBlock value:aValue

!

readValueFrom:aString

    ^ stringToValueBlock value:aString

! !