Get Value returns a single value from a list of values separated by returns (your paragraph symbols). Thus, if the contents of the active field is more than one paragraph of text with paragraphs separated by returns, it will only extract the first paragraph from your script parameter.
This expression will extract a multi-paragraph block of text as the last parameter in your list of values:
Let ( p = Get ( ScriptParameter ) ; RightValues ( p ; ValueCount ( p ) - 2 ) )
Since this leaves a return as the last character you might need to add additional code to strip off that added return if it is not wanted.
You can also use a different method for passign multiple values to your script.
Your parameter expression could be:
"$TableName = "Let ( [ & & Get ( ActiveFieldTableName ) & "; $FieldName = " & Get ( ActiveFieldName ) & "; $Contents = " & Get ( ActiveFieldContents ) & "]; 1 " )
Then use this expression to create the three variables and assign values to them:
Set Variable [$Dummy ; value: Evaluate ( Get (ScriptParameter ) ) ]
Thanks so much PhilModjunk for the quick response and explaination. I think I will use the valuecount approach as I am cleaning up the text anyway so the extra return is not a problem