mirror of
https://github.com/urbit/shrub.git
synced 2024-12-15 12:43:31 +03:00
56 lines
815 B
C
56 lines
815 B
C
/* j/3/tape.c
|
|
**
|
|
*/
|
|
#include "all.h"
|
|
|
|
|
|
/* functions
|
|
*/
|
|
static u3_noun
|
|
_norm(
|
|
u3_noun a)
|
|
{
|
|
if ( c3n == u3du(a) ) {
|
|
return u3_nul;
|
|
} else {
|
|
return u3nc(((c3y == u3du(u3h(a))) ? u3_nul : u3k(u3h(a))),
|
|
_norm(u3t(a)));
|
|
}
|
|
}
|
|
|
|
static u3_noun
|
|
_good(
|
|
u3_noun a)
|
|
{
|
|
while ( 1 ) {
|
|
if ( u3_nul == a ) {
|
|
return c3y;
|
|
}
|
|
if ( c3n == u3ud(u3h(a)) ) {
|
|
return c3n;
|
|
}
|
|
a = u3t(a);
|
|
}
|
|
}
|
|
|
|
u3_noun
|
|
u3qe_tape(u3_noun a)
|
|
{
|
|
if ( c3y == _good(a) ) {
|
|
return u3k(a);
|
|
} else {
|
|
return _norm(a);
|
|
}
|
|
}
|
|
u3_noun
|
|
u3we_tape(u3_noun cor)
|
|
{
|
|
u3_noun a;
|
|
|
|
if ( (u3_none == (a = u3r_at(u3x_sam, cor))) ) {
|
|
return u3m_bail(c3__fail);
|
|
} else {
|
|
return u3qe_tape(a);
|
|
}
|
|
}
|