-- Put this file (or the parts of it you find useful) in your ~/.elinks/hooks.lua, then
-- start elinks and to look up page on a symbol in HyperSpec just type
-- "hs <your symbol>" in location window.

-- One more thing I will tell you: on my machine elinks fails to run lua code if
-- there is any other elinks open.  Just to let you know -- if you see that something
-- is not working, first check this.


-- This one is needed for openfile
---
enable_systems_functions ()


-- I used this for debugging

  debug_file = "/home/jdz/tmp/lua.debug"
  debug_on = 1

function debug (str)
  if debug_on and str then
    f = openfile (debug_file, "a+")
    if f then
      write (f, str)
      write (f, "\n")
      closefile (f)
    end
    -- Someone on irc told me this works for him.  But not for me...
    --xdialog (str)
  end
end




  clhs_root = "file:///usr/share/doc/hyperspec/"
  clhs_map_path = "/usr/share/doc/hyperspec/Data/Map_Sym.txt"

  -- Filled on first use
  clhs_table = nil


-- Loads CLHS symbol map
-- ** Maybe it is possible to use some of the elinks function to fetch
--    the file by URI?
--
function clhs_fill_table (table)
  local fh = openfile (clhs_map_path, "r")

  if fh then
    -- I could not find any sensible looping construct to accomplish this
    local symbol, path
    repeat
      -- read returns nil on EOF
      symbol = read (fh, "*l")
      path = read (fh, "*l")

      if symbol then
        table[symbol] = strsub (path, 4)
      else
        break
      end
    until nil
    closefile (fh)
  else
    debug ("Could not open HyperSpec map file: "..clhs_map_path)
  end
end


function clhs_dump_table (table)
  debug ("table dump:")
  for key, val in table do
    debug (key.." -> "..val)
  end
end


function clhs_lookup (str)

  -- Table not filled yet.  Do it now.
  if not clhs_table then
    clhs_table = {}
    clhs_fill_table (clhs_table)
  end

  str = strupper (str)

  -- This was named suffix once, and I could not understand why my program
  -- does not work.  I don't understand that now, either.  It must be some
  -- kind of *magical* name that lua interpreter doesn't tell I should not
  -- use.
  local url_suffix = clhs_table[str]
  if url_suffix then
    return clhs_root..url_suffix
  else
    debug ("HyperSpec entry for: '"..str.."' not found!")
    return nil
  end
end



function match (prefix, url)
  return strsub (url, 1, strlen (prefix)) == prefix
end



  -- Store the previous value of goto_url_hook.  If we do not process the
  -- url, we call the original handler (if there was one).
  old_goto_url_hook = goto_url_hook

function goto_url_hook (url, current_url)
  -- Common Lisp HyperSpec lookup
  if match ("hs", url) then
    return clhs_lookup (strsub (url, 4))
  else
    if old_goto_url_hook then
      return call (old_goto_url_hook, url, current_url)
    else
      return url
    end
  end
end