This page is for anyone writing text strings in expressions, macros or scripts. It also includes informtion about how to escape special characters.

Using Text Expressions

In PhixFlow, a text expression is made up from a string of characters inside double quotes.  Text expressions can also include variable elements so that data from streams or other PhixFlow items can be inserted into the string. The expression must evaluate to a fixed string.

Escaping Special Characters

When writing expressions you may need to enter a character that has special meaning. For example, a string could include a double-quote, but in the expression PhixFlow will read this as the end of the string. To tell PhixFlow to ignore a special character, you can use the backslash character.  

You must use a backslast to escape any of the special characters listed in the table below.

Example

The following macro escapes special characters. 

do(
    $value = $args[1],
    $value = replaceAll( $value , "\b","\\\\b"),
    $value = replaceAll( $value , "\f","\\\\f"),
    $value = replaceAll( $value , "\t","\\\\t"),
    $value = replaceAll( $value , "\r","\\\\r"),
    $value = replaceAll( $value , "\n","\\\\n"),
    $value = replaceAll( $value , "\\\\","\\\\\\\\"),
    $value = replaceAll( $value , '"','\\\\"')
)