TODO_DESIGN

An attempt at distilling some mainlines from TODO.
None of this points to a yawning abyss of missing functionality.

The last meandering discussion of stacks tied to sinks
meshed with writeto changing output streams is of some interest.


-  (ever) better separate character munging code.
   clearer grip on device whitespace munging and special rules
   for the extreme corner cases.
   (which corner cases? maybe described in TODO).

-  implement append modes \writeto{a}{name}, \write{a}{name}{filter}{stuff}.
   For writeto also make commandline switch that makes \writeto{name}
   append by default.

-  better structuring and sectioning of source code.  parse/segment/digest
   include most of each other, due e.g. to seg_check_ok and yamFormatted1.

-  Env well-formedness should pbb best be checked at output time,
   not during processing time. It should be possible (?) to make
   contrived examples failing during processing time, producing
   correct output nevertheless.
   Well, they would be contrived, so I don't agree with this, but will
   leave the note.

-  better (inode) hashing of file pointers (right now by name, so foo
   and ./foo are different).

-  remove 9-arg limitation.
   Or not. 9 arguments should be enough for anyone. Varargs can already
   be used, and there is some parse support. This could be extended.

-  the implementation of f#2 f#3 and fv#2 is very straightforward
   from a numerical point of view.

-  fix long routines.

-  better special/level design (why/how?)
-  reconsider tracing implementation (why?)



Below seems a discussion prompted by:
-  in zpresent \writeto{} makes env {presentation} inaccessible.


further qualify stacks + dictionaries with associated sink?
or, perhaps,

\get{itemize}{foo}
   will search across all stacks irrespective of sink.

dollarstack tied to output.
default dollarstack: changed by writeto.

aephea:
   \writeto{-}
      \begin{presentation}
   \writeto{1.html}
      \begin{slide}
           \get{$presentation}{foo}
           \write{index.htmL}{device}{.... ??\get{$presentation}{foo}?? ...}
      \end{slide}

write3
      yamOutputNew(fname->str))
      yamKeyDef("__fnwrite__", fname->str)
      yamOutput(yamtxt, xfout->usr, fltidx)
         sinkPush(sk, fltidx)
         sinkPop(sk)

writeto
   yamOutputClose
   yamOutputNew
      if (!xf->usr)
      xf->usr = sinkNew
      else
      filterSetFP
   sinkPush
   ## changed sinkPush: does this fix it?

write

-  in zpresent \writeto{} makes env {presentation} inaccessible.
   1) is there a global dollar stack? (yes, sinkGetDLRdefault)
   2) why is env presentation not tied to it?
      a) is there a way to tie it?
      b) if no, make it.
         -> way to specify that dictionary should be tied to DLRdefault.
         -> OR \writeto should act the same as \write
         -> and optionally make that configurable.