I was reading the 'Problems with do notation' thread and Thomas Schilling suggested reading about mdo. Not knowing mdo I thought that sounds interesting and went to http://haskell.org/ which redirects you to http://haskell.org/haskellwiki/Haskell and gives you a search box. Typing mdo and clicking the Search button gives "Showing below 0 results starting with #1. No page title matches No page text matches Note: unsuccessful searches are often caused by searching for common words like "have" and "from", which are not indexed, or by specifying more than one search term (only pages containing all of the search terms will appear in the result)." Maybe mdo is too common to be indexed? So I went to Google and searched for Haskell mdo and top of the list is this page : http://www.haskell.org/ghc/docs/latest/html/users_guide/syntax-extns.html which is Chapter 8. GHC Language Features 8.3. Syntactic extensions which describes mdo. Did I do something wrong when searching haskell.org? Richard.