ST Get expression

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4D v16.3

ST Get expression


ST Get expression ( {* ;} object {; startSel {; endSel}} ) -> Function result

Parameter	Type	Description
*	Operator	If specified, object is an object name (string) If omitted, object is a field or variable
object	Form object	Object name (if * is specified) or Field or variable (if * is omitted)
startSel	Longint	Start of selection
endSel	Longint	End of selection
Function result	Text	Expression label

Description

The ST Get expression command returns the first expression found in the current selection of the styled text field or variable designated by the object parameter.

The command returns the label of the expression as it was inserted into the object (for example "mymethod" or "[table1]field1"). The current value of the expression is not returned.

Passing the optional * parameter indicates that the object parameter is an object name (string). During execution, if the object has the focus, the command returns the information of the object being edited; if the object does not have the focus, the command returns the information of the object’s data source (variable or field).
If you omit the * 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. During execution, the command returns the information of the variable or field.

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 that may be present.

If you pass startSel and endSel, ST Get expression looks for the expression within this selection.
If you only pass startSel or if the value of endSel is greater than the total number of characters in object, the command looks for the expression between startSel and the end of the text.
If you omit startSel and endSel, the command looks for the expression within the current text selection.

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 endSel is 0), the command does nothing and the OK variable is set to 0.

If there is no expression found in the selection, the command returns an empty string.

Example 1

When there is a double-click event, you check that there is in fact an expression, and if so, you display a dialog where you have retrieved its values so that the user can modify them:

 Case of

    :(Form event=On Double Clicked)

       GET HIGHLIGHT(*;"StyledText_t";startSel;endSel)

       If(ST Get content type(*;"StyledText_t";startSel;endSel)=ST Expression type)

          vExpression:=ST Get expression(*;"StyledText_t";startSel;endSel)

          $winRef:=Open form window("Dial_InsertExpr";Movable form dialog box;Horizontally centered;Vertically centered;*)

          DIALOG("Dial_InsertExpr")

          If(OK=1)

             ST INSERT EXPRESSION(*;"StyledText_t";vExpression;startSel;endSel)

             HIGHLIGHT TEXT(*;"StyledText_t";startSel;endSel)

          End if

       End if

 End case

Example 2

You want to execute a 4D method when a user link is clicked:

 Case of

    :(Form event=On Clicked)

  //we retrieve the selection

       HIGHLIGHT TEXT(*;"myText";startSel;endSel)

       If(startSel#endSel) //there is selected content

  //we get the content type

          $CT_type:=ST Get content type(*;"myText";startSel;endSel)

          If($CT_type=ST User type) //this is a user link

             MyMethod //we execute a 4D method

          End if

       End if

 End case