bugfix for lua.org demo page

demo.lua

local write,D,L,select,tostring,ipairs,concat,execute,sub,gsub=io.write,{},8192,select,tostring,ipairs,table.concat,os.execute,string.sub,string.gsub
local T,E,I
T=io.read"*a"
T=string.match(T,"=(.-)$") or ""
T=gsub(T,"+"," ")
T=gsub(T,"%%(%x%x)",function (x) return string.char(tonumber(x,16)) end)
T=gsub(T,"^%s*=%s*","return ")

write(sub(T,1,L))
write[[</TEXTAREA>
<P>
<INPUT TYPE="submit" VALUE="Run">
<INPUT TYPE="button" VALUE="Clear" onclick="this.form.elements['input'].value=''">
<INPUT TYPE="reset" VALUE="Original">
</FORM>
<P>

<H2>Output</H2>
<TEXTAREA ROWS="8" COLS="80">
]]
io.flush()

arg=nil
debug.debug=nil
debug.getfenv=getfenv
debug.getregistry=nil
dofile=nil
io={write=io.write}
loadfile=nil
os.execute=nil
os.getenv=nil
os.remove=nil
os.rename=nil
os.tmpname=nil
package.loaded.io=io
package.loaded.package=nil
package=nil
require=nil

function write(...)
	for _,v in ipairs{...} do
		v=sub(v,1,L)
		D[#D+1]=v
		L=L-#v
	end
end

T,E=loadstring(T,"=input")
if not T then
	write(E) E="failed to compile" I="alert"
else
	T=(function (...) return {select('#',...),...} end)(pcall(T))
	if not T[2] then
		write(T[3]) E="failed to run" I="alert"
	else
		E="ran successfully" I="ok"
		for i=3,T[1]+1 do write(tostring(T[i]),"\t") end
	end
end
write[[</TEXTAREA><P>]]
write('<IMG SRC="images/',I,'.png" ALIGN="absbottom">\n')
write("Your program ",E,".")
write("<!-- ")

execute("printf '%s\\n' '"..gsub(concat(D),"'","'\\''").."' >&3")

demo.sh

#!/bin/sh

LUA=/home/lhf/websites/lua.org/www/bin/lua
LOG=log
ECHO="/bin/echo -E"

cat <<EOF
Content-type: text/html

EOF

date "+%n@ %c $REMOTE_HOST $REQUEST_METHOD $HTTP_REFERER" >> $LOG
if [ "$REQUEST_METHOD" = "GET" ]
then
	if [ "$QUERY_STRING" = "" ]
	then
		exec cat demo.html
	else
		$ECHO "$QUERY_STRING" >> $LOG
		F=`basename -- "$QUERY_STRING"`.lua
		sed '/TEXTAREA/q' demo.html
		$ECHO "-- $F"
		(cat -- "$F" 2>&1)
		sed '1,/TEXTAREA/d' demo.html
	fi
else
	sed '/TEXTAREA/q' demo.html
	tee -a $LOG | (ulimit -t 1 ; { res=$($LUA demo.lua 3>&1 >&4 2>&4 4>&-); } 4>&1 ; printf "%s\n" "$res")

	cat <<EOF

</TEXTAREA><P><IMG SRC="images/alert.png" ALIGN="absbottom">
Your program was aborted.<!-- -->
<P>

<HR>
<SMALL>
EOF
	$LUA -v 2>&1
	cat <<EOF
</SMALL>

</BODY>
</HTML>
EOF
	echo '' >> $LOG
fi