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https://github.com/urbit/shrub.git
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215 lines
4.8 KiB
C
215 lines
4.8 KiB
C
/* j/6/peek.c
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**
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*/
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#include "all.h"
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/* logic
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*/
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u3_noun
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_cqzu_peek(u3_noun, u3_noun, u3_noun, u3_atom);
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static u3_noun
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_peek_in(u3_noun, u3_noun, u3_noun, u3_atom, u3_noun);
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static u3_noun
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_peek_fork(u3_noun van, u3_noun p_sut, u3_noun way, u3_noun axe, u3_noun gil)
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{
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if ( u3_nul == p_sut ) {
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return u3_nul;
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}
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else {
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return u3nc(_peek_in(van, u3h(p_sut), way, axe, gil),
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_peek_fork(van, u3t(p_sut), way, axe, gil));
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}
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}
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static u3_noun
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_peek_in(u3_noun van,
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u3_noun sut,
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u3_noun way,
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u3_atom axe,
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u3_noun gil)
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{
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u3_noun p_sut, q_sut;
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u3_noun pro;
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if ( (c3n == u3du(sut)) ) switch ( sut ) {
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default: return u3m_bail(c3__fail);
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case c3__noun: {
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return c3__noun;
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}
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case c3__void: {
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return c3__void;
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}
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}
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else switch ( u3h(sut) ) {
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default: return u3m_bail(c3__fail);
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case c3__atom: {
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return c3__void;
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}
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case c3__cell: {
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if ( (c3n == u3r_trel(sut, 0, &p_sut, &q_sut)) ) {
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return u3m_bail(c3__fail);
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} else {
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u3_atom tip = u3qc_cap(axe);
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u3_atom tap = u3qc_mas(axe);
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if ( 2 == tip ) {
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pro = _cqzu_peek(van, p_sut, way, tap);
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}
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else {
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pro = _cqzu_peek(van, q_sut, way, tap);
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}
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u3z(tap);
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u3z(tip);
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return pro;
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}
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}
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case c3__core: {
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u3_noun pq_sut, qq_sut, rq_sut;
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u3_noun prq_sut, qrq_sut;
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if ( (c3n == u3r_trel(sut, 0, &p_sut, &q_sut)) ||
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(c3n == u3r_trel(q_sut, &pq_sut, &qq_sut, &rq_sut)) ||
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(c3n == u3r_cell(rq_sut, &prq_sut, &qrq_sut)) )
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{
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return u3m_bail(c3__fail);
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} else {
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u3_atom now = u3qc_cap(axe);
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u3_atom lat = u3qc_mas(axe);
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if ( 3 == now ) {
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u3_noun pec = u3qzu_peel(van, sut, way, pq_sut);
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u3_noun sam = u3h(pec);
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u3_noun con = u3t(pec);
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if ( c3y == c3a(sam, con) ) {
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pro = _cqzu_peek(van, p_sut, way, lat);
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}
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else {
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u3_noun typ;
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{
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u3_noun hed, tal;
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if ( c3n == sam ) {
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hed = c3__noun;
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} else {
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hed = _cqzu_peek(van, p_sut, way, 2);
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}
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if ( c3n == con ) {
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tal = c3__noun;
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} else {
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tal = _cqzu_peek(van, p_sut, way, 3);
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}
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typ = u3qz_cell(hed, tal);
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u3z(hed);
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u3z(tal);
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}
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pro = _cqzu_peek(van, typ, way, lat);
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u3z(typ);
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}
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u3z(pec);
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}
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else {
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pro = c3__noun;
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}
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u3z(lat);
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u3z(now);
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return pro;
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}
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}
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case c3__help:
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case c3__face: {
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if ( (c3n == u3r_trel(sut, 0, &p_sut, &q_sut)) ) {
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return u3m_bail(c3__fail);
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} else {
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return _peek_in(van, q_sut, way, axe, gil);
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}
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}
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case c3__fork: p_sut = u3t(sut);
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{
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u3_noun yed = u3qdi_tap(p_sut, u3_nul);
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u3_noun ret = u3kf_fork(_peek_fork(van, yed, way, axe, gil));
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u3z(yed);
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return ret;
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}
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case c3__hold: {
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if ( (c3y == u3qdi_has(gil, sut)) ) {
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return c3__void;
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}
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else {
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u3_noun zoc = u3qdi_put(gil, sut);
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u3_noun fop = u3qzu_repo(van, sut);
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u3_noun pro = _peek_in(van, fop, way, axe, zoc);
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u3z(fop);
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u3z(zoc);
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return pro;
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}
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}
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}
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}
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u3_noun
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_cqzu_peek(u3_noun van,
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u3_noun sut,
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u3_noun way,
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u3_atom axe)
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{
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if ( 1 == axe ) {
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return u3k(sut);
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}
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else return _peek_in(van, sut, way, axe, u3_nul);
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}
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/* boilerplate
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*/
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u3_noun
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u3wzu_peek(u3_noun cor)
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{
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u3_noun sut, way, axe, van;
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if ( (c3n == u3r_mean(cor, u3x_sam_2, &way,
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u3x_sam_3, &axe,
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u3x_con, &van,
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0)) ||
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(c3n == u3ud(axe)) ||
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(u3_none == (sut = u3r_at(u3x_sam, van))) )
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{
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return u3m_bail(c3__fail);
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} else {
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return _cqzu_peek(van, sut, way, axe);
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}
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}
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u3_noun
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u3qzu_peek(u3_noun van,
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u3_noun sut,
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u3_noun way,
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u3_noun axe)
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{
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c3_m fun_m = 144 + c3__peek + ((!!u3r_at(u3qzu_van_vet, van)) << 8);
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u3_noun pro = u3z_find_3(fun_m, sut, way, axe);
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if ( u3_none != pro ) {
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return pro;
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}
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else {
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pro = _cqzu_peek(van, sut, way, axe);
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return u3z_save_3(fun_m, sut, way, axe, pro);
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}
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}
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