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Resurrect quasisyntax support.

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* mes.c (the_unsyntaxers): New symbol.
  (mes_builtins)[QUASISYNTAX]: Initialize it, add to environment.
* quasiquote.c (add_unsyntaxers): Use it.
  (vm_eval_quasisyntax): New function.
  (eval_quasisyntax): Use it.
This commit is contained in:
Jan Nieuwenhuizen 2016-12-16 15:10:03 +01:00
parent e8b78a1077
commit 15eabee623
2 changed files with 31 additions and 12 deletions
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11
mes.c
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@ -122,6 +122,7 @@ scm scm_symbol_primitive_load = {SYMBOL, "primitive-load"};
scm scm_symbol_read_input_file = {SYMBOL, "read-input-file"};
scm scm_symbol_the_unquoters = {SYMBOL, "*the-unquoters*"};
scm scm_symbol_the_unsyntaxers = {SYMBOL, "*the-unsyntaxers*"};
scm scm_symbol_car = {SYMBOL, "car"};
scm scm_symbol_cdr = {SYMBOL, "cdr"};
@ -445,7 +446,7 @@ vm_eval_env ()
#endif // FIXED_PRIMITIVES
case cell_symbol_quote: return cadr (r1);
#if QUASISYNTAX
case cell_symbol_syntax: return r1;
case cell_symbol_syntax: return cadr (r1);
#endif
case cell_symbol_begin: return begin_env (r1, r0);
case cell_symbol_lambda:
@ -1129,6 +1130,14 @@ mes_builtins (SCM a)
cell_nil));
a = acons (cell_symbol_the_unquoters, the_unquoters, a);
#endif
#if QUASISYNTAX
SCM cell_unsyntax = assq_ref_cache (cell_symbol_unsyntax, a);
SCM cell_unsyntax_splicing = assq_ref_cache (cell_symbol_unsyntax_splicing, a);
SCM the_unsyntaxers = cons (cons (cell_symbol_unsyntax, cell_unsyntax),
cons (cons (cell_symbol_unsyntax_splicing, cell_unsyntax_splicing),
cell_nil));
a = acons (cell_symbol_the_unsyntaxers, the_unsyntaxers, a);
#endif
a = add_environment (a, "*dot*", cell_dot);
a = add_environment (a, "*foo-bar-baz*", cell_nil); // FIXME: some off-by one?

32
quasiquote.c
View file

@ -93,22 +93,31 @@ unsyntax_splicing (SCM x) ///((no-environment))
SCM
eval_quasisyntax (SCM e, SCM a)
{
if (e == cell_nil) return e;
else if (atom_p (e) == cell_t) return e;
else if (eq_p (car (e), cell_symbol_unsyntax) == cell_t)
return eval_env (cadr (e), a);
else if (TYPE (e) == PAIR && TYPE (car (e)) == PAIR
&& eq_p (caar (e), cell_symbol_unsyntax_splicing) == cell_t)
return append2 (eval_env (cadar (e), a), eval_quasisyntax (cdr (e), a));
return cons (eval_quasisyntax (car (e), a), eval_quasisyntax (cdr (e), a));
return vm_call (vm_eval_quasisyntax, e, cell_undefined, a);
}
SCM
vm_eval_quasisyntax ()
{
if (r1 == cell_nil) return r1;
else if (atom_p (r1) == cell_t) return r1;
else if (eq_p (car (r1), cell_symbol_unsyntax) == cell_t)
return eval_env (cadr (r1), r0);
else if (TYPE (r1) == PAIR && TYPE (car (r1)) == PAIR
&& eq_p (caar (r1), cell_symbol_unsyntax_splicing) == cell_t)
{
r2 = eval_env (cadar (r1), r0);
return append2 (r2, eval_quasisyntax (cdr (r1), r0));
}
r2 = eval_quasisyntax (car (r1), r0);
return cons (r2, eval_quasisyntax (cdr (r1), r0));
}
SCM
add_unsyntaxers (SCM a)
{
a = cons (cons (cell_symbol_unsyntax, cell_unsyntax), a);
a = cons (cons (cell_symbol_unsyntax_splicing, cell_unsyntax_splicing), a);
return a;
SCM q = assq_ref_cache (cell_symbol_the_unsyntaxers, a);
return append2 (q, a);
}
#else // !QUASISYNTAX
@ -117,5 +126,6 @@ SCM unsyntax (SCM x){}
SCM unsyntax_splicing (SCM x){}
SCM add_unsyntaxers (SCM a){}
SCM eval_quasisyntax (SCM e, SCM a){}
SCM vm_eval_quasisyntax () {}
#endif // !QUASISYNTAX