Escaping of URI with encode-for-uri(), iri-to-uri(), and escape-html-uri()

The function encode-for-uri() escapes characters which can cause problems in path segments of URL addresses. All characters are escaped other than the lower case letters a-z, the upper case letters A-Z, the digits 0-9, the NUMBER SIGN "#" and HYPHEN-MINUS ("-"), LOW LINE ("_"), FULL STOP ".", EXCLAMATION MARK "!", TILDE "~", ASTERISK "*", APOSTROPHE "'", LEFT PARENTHESIS "(", and RIGHT PARENTHESIS ")".

The function iri-to-uri() should be used for strings intended as URL addresses. All characters are escaped other than the lower case letters a-z, the upper case letters A-Z, the digits 0-9, the NUMBER SIGN "#" and HYPHEN-MINUS ("-"), LOW LINE ("_"), FULL STOP ".", EXCLAMATION MARK "!", TILDE "~", ASTERISK "*", APOSTROPHE "'", LEFT PARENTHESIS "(", and RIGHT PARENTHESIS ")", SEMICOLON ";", SOLIDUS "/", QUESTION MARK "?", COLON ":", COMMERCIAL AT "@", AMPERSAND "&", EQUALS SIGN "=", PLUS SIGN "+", DOLLAR SIGN "$", COMMA ",", LEFT SQUARE BRACKET "[", RIGHT SQUARE BRACKET "]", and the PERCENT SIGN "%".

The function escape-html-uri() escapes all characters except printable characters of the US-ASCII coded character set, specifically the octets ranging from 32 to 126 (decimal). The effect of the function is to escape a URI in the manner html user agents handle attribute values that expect URIs. Each character in $uri to be escaped is replaced by an escape sequence, which is formed by encoding the character as a sequence of octets in UTF-8, and then representing each of these octets in the form %HH, where HH is the hexadecimal representation of the octet. This function must always generate hexadecimal values using the upper-case letters A-F. This function is not implemented in saxon 8.6 at this moment (22nd Nov 2005), please send me an email if you find this sentence after March 2006)