1
1
mirror of https://github.com/urbit/shrub.git synced 2024-12-22 02:11:38 +03:00
shrub/gen164/5/tape.c
2014-09-03 20:10:43 -07:00

57 lines
880 B
C

/* j/3/tape.c
**
** This file is in the public domain.
*/
#include "all.h"
/* functions
*/
static u2_noun
_norm(
u2_noun a)
{
if ( u2_no == u2du(a) ) {
return u2_nul;
} else {
return u2nc(((u2_yes == u2du(u2h(a))) ? u2_nul : u2k(u2h(a))),
_norm(u2t(a)));
}
}
static u2_bean
_good(
u2_noun a)
{
while ( 1 ) {
if ( u2_nul == a ) {
return u2_yes;
}
if ( u2_no == u2ud(u2h(a)) ) {
return u2_no;
}
a = u2t(a);
}
}
u2_noun
u2_cqe_tape(u2_noun a)
{
if ( u2_yes == _good(a) ) {
return u2k(a);
} else {
return _norm(a);
}
}
u2_noun
u2_cwe_tape(u2_noun cor)
{
u2_noun a;
if ( (u2_none == (a = u2_cr_at(u2_cv_sam, cor))) ) {
return u2_cm_bail(c3__fail);
} else {
return u2_cqe_tape(a);
}
}