The Escape(s, form) command escapes special characters in the input string s, according to rules specified by the optional second argument form.

The form argument defaults to xml, which specifies that rules appropriate for including the text of the string s in an XML document are to be used.

Alternatively, the form argument can be the symbol html. Escaping rules suitable for HTML text are then used.

If the form argument is regexp, then the input is taken to be a regular expression, and is escaped in such a way that RegMatch( Escape( rx, 'regexp' ), rx ) returns true, for any regular expression rx.

All of the StringTools package commands treat strings as (null-terminated) sequences of $8$-bit (ASCII) characters.  Thus, there is no support for multibyte character encodings, such as unicode encodings.

$\mathrm{with}\left(\mathrm{StringTools}\right)\:$

$r≔\mathrm{Escape}\left(''Some\; text\; with\text{'}embedded\text{'}\; HTML.''\right)\:$$\mathrm{lprint}\left(r\right)$

"Some text with <b>'embedded' HTML</b>."

$r≔\mathrm{Escape}\left(''Some\; text\; with\text{'}embedded\text{'}\; HTML.''\,'\mathrm{xml}'\right)\:$$\mathrm{lprint}\left(r\right)$

"Some text with <b>'embedded' HTML</b>."

$r≔\mathrm{Escape}\left(''Some\; text\; with\text{'}embedded\text{'}\; HTML.''\,'\mathrm{html}'\right)\:$$\mathrm{lprint}\left(r\right)$

"Some text with <b>'embedded' HTML</b>."

$\mathrm{rx}≔''0x([0-9a-f]+|[0-9A-F]+)\$''\:$

$r≔\mathrm{Escape}\left(\mathrm{rx}\,'\mathrm{regexp}'\right)\:$$\mathrm{lprint}\left(r\right)$

"0x\\(\\[0-9a-f\\]\\+\\|\\[0-9A-F\\]\\+\\)\\$"

$\mathrm{RegMatch}\left(r\,\mathrm{rx}\right)$

$\mathrm{true}$