Escape literal beginning at (@) strings from qdapRegex parsing.
Usage
escape(pattern)
Value
Returns a character vector of the class "escape" and "character".
Arguments
pattern
A character string that should not be parsed.
Details
Many qdapRegex functions parse pattern strings
beginning with an at character (@) and comparing against the default and
supplemental (regex_supplement) dictionaries. This
means that a string such as "@before_" will be returned as
"\\w+?(?= ((%s|%s)\\b))". If the user wanted to use a regular
expression that was literally "@before_" the escape function classes
the character string and tells the qdapRegex functions not to parse it
(i.e., keep it as a literal string).