Normally if i indent by 4 spaces, the text will format as computer code, for example,

int main () {
...
}

but it doesn't work for [ [ foobar ] ] (remove the space between the two square brackets). It will expose code like:

<span class="createlink"><a href="/ikiwiki.cgi?do=create&amp;from=forum%2FHow_to_format___91____91__foobar__93____93___in_code_blocks__63__&amp;page=foobar" rel="nofollow">?</a>foobar</span>