references now have a new appearance which is more compact and
also gives a clue about what the target of the reference is.
By setting parameters in the print state, more fancy printing can
be achieved. This is used by the (not yet commited) backtrace
code.
* print.c: Added #include "struct.h". Removed function
scm_prlist.
* print.c (scm_prin1): Print states are now allocated when calling
scm_prin1 and then passed around to all printing functions as an
argument. A cache `print_state_pool' enables reuse of print
states.
(scm_make_print_state): New function.
(scm_iprin1): Adaption to print states.
(scm_iprlist): An initial "hare and tortoise" scan brings down
time complexity to O (depth * N). (Better time complexity will be
achieved when the printing code is completely rewritten.)
* print.c, print.h: Closures now print like #<procedure foo (x)>.
People who whish to see the source can do `(print-enable 'source)'.
Removed #ifdef DEBUG_EXTENSIONS.
printing. (init_ref_stack, grow_ref_stack): New functions. Added
a hook for printing of closures (accessible via print options).
This leads to a split of calls to scm_iprin1 into two classes:
elementary print operations (e. g. the code which prints a smob)
still use scm_iprin1 while top level calls (like scm_display) use
scm_prin1. scm_prin1 begins by clearing the data structure used
to record reference information.
