Hello all,

In TeX, to save a series of catcodes one might do something like:

\edef\savedcatcodes{%
  \catcode\string`\string ` \the\catcode\string`\`\relax
  \catcode\string`\string = \the\catcode\string`\=\relax
  \catcode\string`\string ^ \the\catcode\string`\^\relax
  \catcode\string`\string _ \the\catcode\string`\_\relax
  \catcode\string`\string ~ \the\catcode\string`\~\relax
  \catcode\string`\string : \the\catcode\string`\:\relax
  \catcode\string`\string - \the\catcode\string`\-\relax
  \catcode\string`\string + \the\catcode\string`\+\relax
  \catcode\string`\string ; \the\catcode\string`\;\relax
  \catcode\string`\string , \the\catcode\string`\,\relax
  \catcode\string`\string . \the\catcode\string`\.\relax}

the use \savedcatcodes later to restore them.  Achieving the same in
expl3 seems to be driving me round the bend.  I can't figure out what
the correct syntax is for \char_value_catcode:n and \char_set_catcode:nn
under these circumstances.  Any chance of a clue?
-- 
Joseph Wright