HtmlDecode - ObjectVision/GeoDMS GitHub Wiki

String functions HtmlDecode

The HtmlDecode function decodes HTML-encoded strings back to their original form.

HtmlDecode(strings: E->String) -> E->String

Converts HTML-encoded strings back to their original format by replacing HTML entity references with the corresponding characters:

The first five are the predefined XML/HTML entities that HtmlEncode produces, so HtmlDecode(HtmlEncode(x)) returns x.   is accepted as well because it is ubiquitous in HTML, although HtmlEncode never produces it.

Also decodes numeric character references, decimal < as well as hexadecimal <, emitting the code point as UTF-8.

Anything that is not a reference this function knows is copied through verbatim rather than being an error: an unknown name (&unknown;), an unterminated reference (&amp x) and an out-of-range numeric reference all stay as they are, since that is what the input meant literally. < therefore decodes to <, not to <: decoding is applied once, not repeatedly.

Time complexity: O(n × L) where n is the number of strings and L is the average string length.

Decoded strings are typically slightly shorter than input strings.

unit<uint32> HtmlContent: nrofrows = 3;
attribute<String> encoded (HtmlContent) := union_data(HtmlContent,
    'Hello &lt;world&gt;',
    'A &amp; B',
    'Quote: &quot;test&quot;'
);

attribute<String> decoded (HtmlContent) := HtmlDecode(encoded);
// decoded = {'Hello <world>', 'A & B', 'Quote: "test"'}

• Processing data extracted from HTML sources
• Converting HTML content to plain text
• Cleaning up HTML entity artifacts in imported data

• HtmlEncode - reverse operation
• UrlDecode - for URL parameters
• String functions

20.13.0