4D v14.3

ST FREEZE EXPRESSIONS

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4D v14.3
ST FREEZE EXPRESSIONS

ST FREEZE EXPRESSIONS 


 

ST FREEZE EXPRESSIONS ( {* ;} object {; startSel {; endSel}}{; *} ) 
Parameter Type   Description
Operator in If specified, object is an object name (string) If omitted, object is a field or variable
object  Form object in Object name (if * is specified) or Field or variable (if * is omitted)
startSel  Longint in Start of selection
endSel  Longint in End of selection
Operator in If passed = update expressions before freezing them

The ST FREEZE EXPRESSIONS command "freezes" the contents of expressions found in the styled text field or variable designated by the object parameter. This action converts dynamic expressions into static text and removes the associated references from the object

For more information about 4D expressions used in multi-style text areas, refer to the description of the ST INSERT EXPRESSION command.

The ST FREEZE EXPRESSIONS command stores the computed value of an expression at a given time. This operation is necessary particularly before each use of the object outside of a multi-style area (exports, storage in a disk file, printing, etc.) since only the reference of the expression is kept in the area itself. 

Passing the optional * parameter indicates that the object parameter is an object name (string). If you do not pass this parameter, it indicates that the object parameter is a field or variable. In this case, you pass a field or variable reference instead of a string (field or variable object only).

The optional startSel and endSel parameters designate a selection of text in object. The startSel and endSel values express a plain text selection, without taking into account any style tags or references that may be present.

  • If you pass startSel and endSel, ST FREEZE EXPRESSIONS only freezes the expressions located within this selection.
  • If you only pass startSel or if the value of endSel is greater than the total number of characters in the object, all the expressions between startSel and the end of the text are frozen.
  • If you omit startSel and endSel, all the expressions included in the user selection of the object are frozen.

4D provides predefined constants so that you can designate the selection limits automatically in the startSel and endSel parameters.
These constants are found in the "Multistyle Text" theme: 

Constant Type Value Comment
ST End highlight Longint -1001 Designates last character of current text selection in object (*)
ST End text Longint 0 Designates last character of text contained in object
ST Start highlight Longint -1000 Designates first character of current text selection in object (*)
ST Start text Longint 1 Designates first character of text contained in object
  

(*) You must pass an object name in object to be able to use this constant. If you pass a reference to a field or variable, the command is applied to all the text of the object.

Note: If startSel is greater than endSel (except when endSelis 0), the command does nothing and the OK variable is set to 0.

By default, expressions are not re-evaluated before they are frozen. If you want the expression to be recomputed and then frozen, you can pass the second * parameter.

Example  

You want to insert the current time at the start of the text and then freeze it before saving the record:

  //Inserting the time at the start of the text
 ST INSERT EXPRESSION(*;StyledText_t;"Current time";1)
  //We freeze the expression
 ST FREEZE EXPRESSIONS(*;"StyledText_t";1)

 
PROPERTIES 

Product: 4D
Theme: Styled Text
Number: 1282

 
HISTORY 

New
Created: 4D v14

 
SEE ALSO 

ST COMPUTE EXPRESSIONS
ST INSERT EXPRESSION

 
ARTICLE USAGE

4D Language Reference ( 4D v14 R2)
4D Language Reference ( 4D v14 R3)
4D Language Reference ( 4D v14.3)
4D Language Reference ( 4D v14 R4)