urbit/j/f/ut_swab.c
2015-02-10 15:13:17 -08:00

60 lines
1.1 KiB
C

/* j/6/swab.c
**
*/
#include "all.h"
/* internals
*/
/* functions
*/
u3_noun
_cqfu_snub(u3_noun van,
u3_noun sut,
u3_noun har)
{
if ( c3n == u3du(har) ) {
return u3_nul;
} else {
u3_noun i_har = u3h(har);
u3_noun t_har = u3t(har);
u3_noun pi_har = u3h(i_har);
u3_noun qi_har = u3t(i_har);
u3_noun peh = u3qb_flop(pi_har);
u3_noun ret = u3nc(u3nc(peh, u3k(qi_har)),
_cqfu_snub
(van, sut, t_har));
return ret;
}
}
/* boilerplate
*/
u3_noun
u3wfu_snub(
u3_noun cor)
{
u3_noun van, sut, har;
if ( (c3n == u3r_mean(cor, u3x_sam, &har,
u3x_con, &van,
0)) ||
(u3_none == (sut = u3r_at(u3x_sam, van))) )
{
return u3m_bail(c3__fail);
} else {
return _cqfu_snub(van, sut, har);
}
}
u3_noun
u3qfu_snub(u3_noun van,
u3_noun sut,
u3_noun har)
{
return _cqfu_snub(van, sut, har);
}