@main[]

$s[ 
	^taint[html][ some <a href="/?a&b">html</a> code ]
	^taint[parser-code][ ^$b(2+2) ]
	^taint[regex][ ^^(.*?)^$ ]
	^taint[ some <?dirty?> code ]
]

^apply-taint[$s]
^apply-taint[html;$s]
^apply-taint[regex;$s]

$f[^file::exec[cat^os[-windows].sh; $.stdin[$s] ;stdin]]
$f.text

code coverage tests:

2. ^try-catch{ ^file::exec[cat^os[-windows].sh; $.HTTP_OK[value] $.CGI_OK[value] $.REMOTE_ADDR[allowed]  $.unsafe_env_name[env_value] ] }
3. ^try-catch{ ^file::exec[text] }
4. ^try-catch{ ^file::exec[cat^os[-windows].sh; $.stdin[ $.hash[] ] ] }
5. ^try-catch{ ^file::exec[cat^os[-windows].sh; ;arg1;^table::create[nameless]{arg2}; $.arg_hash[] ] }