diff options
Diffstat (limited to 'Master/texmf-dist/tex/luatex/luatexja/ltj-jfmglue.lua')
-rw-r--r-- | Master/texmf-dist/tex/luatex/luatexja/ltj-jfmglue.lua | 344 |
1 files changed, 207 insertions, 137 deletions
diff --git a/Master/texmf-dist/tex/luatex/luatexja/ltj-jfmglue.lua b/Master/texmf-dist/tex/luatex/luatexja/ltj-jfmglue.lua index 3a7101e827d..7c5ba8661aa 100644 --- a/Master/texmf-dist/tex/luatex/luatexja/ltj-jfmglue.lua +++ b/Master/texmf-dist/tex/luatex/luatexja/ltj-jfmglue.lua @@ -296,9 +296,13 @@ local function calc_np_pbox(lp, last) Np.first = Np.first or lp; Np.id = id_pbox set_attr(lp, attr_icflag, get_attr_icflag(lp)); while lp ~=last and (lpa>=PACKED) and (lpa<BOXBDD) do - if getid(lp)==id_hlist or getid(lp)==id_vlist then + local lpi = getid(lp) + if lpi==id_hlist or lpi==id_vlist then head, lp, nc = ltjd_make_dir_whatsit(head, lp, list_dir, 'jfm pbox') Np.first = first and nc or Np.first + elseif (lpi==id_rule) and (lpa==PACKED) then + lp = node_next(lp) + nc, lp = lp, node_next(lp) else nc, lp = lp, node_next(lp) end @@ -319,9 +323,9 @@ local function calc_np_aux_glyph_common(lp) Np.first= (Np.first or lp) if getfield(lp, 'lang') == lang_ja then Np.id = id_jglyph - local m, cls = set_np_xspc_jachar(Np, lp) + local m, mc, cls = set_np_xspc_jachar(Np, lp) local npi, npf - lp, head, npi, npf = capsule_glyph(lp, m, cls, head, tex_dir, lp) + lp, head, npi, npf = capsule_glyph(lp, m, mc[cls], head, tex_dir) Np.first = (Np.first~=Np.nuc) and Np.first or npf or npi Np.nuc = npi return true, check_next_ickern(lp); @@ -567,6 +571,7 @@ do c = c or c_glyph local cls = slow_find_char_class(c, m, c_glyph) Nx.met, Nx.class, Nx.char = m, cls, c; + local mc = m.char_type; Nx.char_type = mc if cls~=0 then set_attr(x, attr_jchar_class, cls) end if c~=c_glyph then set_attr(x, attr_jchar_code, c) end Nx.pre = table_current_stack[PRE + c] or 0 @@ -574,12 +579,13 @@ do Nx.xspc = table_current_stack[XSP + c] or 3 Nx.kcat = table_current_stack[KCAT + c] or 0 Nx.auto_kspc, Nx.auto_xspc = (has_attr(x, attr_autospc)==1), (has_attr(x, attr_autoxspc)==1) - return m, cls + return m, mc, cls end function set_np_xspc_jachar_hbox(Nx, x) local m = ltjf_font_metric_table[getfont(x)] local c = has_attr(x, attr_jchar_code) or getchar(x) Nx.met, Nx.char = m, c; Nx.class = has_attr(x, attr_jchar_class) or 0; + local mc = m.char_type; Nx.char_type = mc Nx.pre = table_current_stack[PRE + c] or 0 Nx.post = table_current_stack[POST + c] or 0 Nx.xspc = table_current_stack[XSP + c] or 3 @@ -682,20 +688,20 @@ local function handle_penalty_suppress(post, pre, g) end -- 和文文字間の JFM glue を node 化 -local function new_jfm_glue(m, bc, ac) +local function new_jfm_glue(mc, bc, ac) -- bc, ac: char classes - local g = m.char_type[bc][ac] + local g = mc[bc][ac] if g then if g[1] then local f = node_new(id_glue) - set_attr(f, attr_icflag, g[4]) + set_attr(f, attr_icflag, g.priority) setfield(f, 'spec', node_copy(g[2])) - return f, g[3] + return f, g.ratio, g.kanjiskip_natural, g.kanjiskip_stretch, g.kanjiskip_shrink else - return node_copy(g[2]), g[3] + return node_copy(g[2]), g.ratio, false, false, false end end - return nil, 0 + return false, 0 end -- Nq.last (kern w) .... (glue/kern g) Np.first @@ -708,50 +714,6 @@ end -------------------- 和文文字間空白量の決定 -local null_skip_table = {0, 0, 0} --- get kanjiskip -local get_kanjiskip -local get_kanjiskip_normal, get_kanjiskip_jfm -do - local KANJI_SKIP = luatexja.icflag_table.KANJI_SKIP - local KANJI_SKIP_JFM = luatexja.icflag_table.KANJI_SKIP_JFM - get_kanjiskip_normal = function () - if Np.auto_kspc or Nq.auto_kspc then - return node_copy(kanji_skip) - else - local g = node_copy(zero_glue) - set_attr(g, attr_icflag, KANJI_SKIP) - return g - end - end - - get_kanjiskip_jfm = function () - local g - if Np.auto_kspc or Nq.auto_kspc then - g = node_new(id_glue); --copy_attr(g, Nq.nuc) - local gx = node_new(id_glue_spec); - setfield(gx, 'stretch_order', 0); setfield(gx, 'shrink_order', 0) - local pm, qm = Np.met, Nq.met - local bk = qm.kanjiskip or null_skip_table - if (pm.char_type==qm.char_type) and (qm.var==pm.var) then - setfield(gx, 'width', bk[1]) - setfield(gx, 'stretch', bk[2]) - setfield(gx, 'shrink', bk[3]) - else - local ak = pm.kanjiskip or null_skip_table - setfield(gx, 'width', round(diffmet_rule(bk[1], ak[1]))) - setfield(gx, 'stretch', round(diffmet_rule(bk[2], ak[2]))) - setfield(gx, 'shrink', -round(diffmet_rule(-bk[3], -ak[3]))) - end - setfield(g, 'spec', gx) - else - g = node_copy(zero_glue) - end - set_attr(g, attr_icflag, KANJI_SKIP_JFM) - return g - end -end - local calc_ja_ja_aux do local bg_ag = 2*id_glue - id_glue @@ -759,12 +721,13 @@ do local bk_ag = 2*id_kern - id_glue local bk_ak = 2*id_kern - id_kern - calc_ja_ja_aux = function (gb,ga, db, da) - local rbb, rab = 0.5*(1-db), 0.5*(1-da) -- 「前の文字」由来のグルーの割合 - local rba, raa = 0.5*(1+db), 0.5*(1+da) -- 「前の文字」由来のグルーの割合 + local function blend_diffmet(b, a, rb, ra) + return round(diffmet_rule((1-rb)*b+rb*a, (1-ra)*b+ra*a)) + end + calc_ja_ja_aux = function (gb, ga, db, da) if diffmet_rule ~= math.two_pleft and diffmet_rule ~= math.two_pright and diffmet_rule ~= math.two_paverage then - rbb, rab, rba, raa = 1,0,0,1 + db, da = 0, 1 end if not gb then if ga then @@ -778,126 +741,234 @@ do if k == bg_ag then local bs, as = getfield(gb, 'spec'), getfield(ga, 'spec') -- 両方とも glue. - local bd, ad = getfield(bs, 'width'), getfield(as, 'width') - setfield(bs, 'width', round(diffmet_rule(rbb*bd + rba*ad, rab*bd + raa*ad))) - bd, ad = getfield(bs, 'stretch'), getfield(as, 'stretch') - setfield(bs, 'stretch', round(diffmet_rule(rbb*bd + rba*ad, rab*bd + raa*ad))) - bd, ad = getfield(bs, 'shrink'), getfield(as, 'shrink') - setfield(bs, 'shrink', -round(diffmet_rule(-rbb*bd - rba*ad, -rab*bd - raa*ad))) + setfield(bs, 'width', blend_diffmet( + getfield(bs, 'width'), getfield(as, 'width'), db, da)) + setfield(bs, 'stretch', blend_diffmet( + getfield(bs, 'stretch'), getfield(as, 'stretch'), db, da)) + setfield(bs, 'shrink', -blend_diffmet( + -getfield(bs, 'shrink'), -getfield(as, 'shrink'), db, da)) node_free(ga) return gb elseif k == bk_ak then -- 両方とも kern. - local bd, ad = getfield(gb, 'kern'), getfield(ga, 'kern') - setfield(gb, 'kern', round(diffmet_rule(rbb*bd + rba*ad, rab*bd + raa*ad))) + setfield(gb, 'kern', blend_diffmet( + getfield(gb, 'kern'), getfield(ga, 'kern'), db, da)) node_free(ga) return gb elseif k == bk_ag then local as = getfield(ga, 'spec') -- gb: kern, ga: glue - local bd, ad = getfield(gb, 'kern'), getfield(as, 'width') - setfield(as, 'width', round(diffmet_rule(rbb*bd + rba*ad, rab*bd + raa*ad))) - ad = getfield(as, 'stretch') - setfield(bs, 'stretch', round(diffmet_rule(rba*ad, raa*ad))) - ad = getfield(as, 'shrink') - setfield(bs, 'shrink', -round(diffmet_rule(-rba*ad, -raa*ad))) + setfield(as, 'width', blend_diffmet( + getfield(gb, 'kern'), getfield(as, 'width'), db, da)) + setfield(as, 'stretch', blend_diffmet( + 0, getfield(as, 'stretch'), db, da)) + setfield(as, 'shrink', -blend_diffmet( + 0, -getfield(as, 'shrink'), db, da)) node_free(gb) - return ga + return ga, 0, 0, 0 else local bs = getfield(gb, 'spec') -- gb: glue, ga: kern - local bd, ad = getfield(bs, 'width'), getfield(ga, 'kern') - setfield(bs, 'width', round(diffmet_rule(rbb*bd + rba*ad, rab*bd + raa*ad))) - bd = getfield(bs, 'stretch') - setfield(bs, 'stretch', round(diffmet_rule(rbb*bd, rab*bd))) - bd = getfield(bs, 'shrink') - setfield(bs, 'shrink', -round(diffmet_rule(-rbb*bd, -rab*bd))) + setfield(bs, 'width', blend_diffmet( + getfield(bs, 'width'), getfield(ga, 'kern'), db, da)) + setfield(bs, 'stretch', blend_diffmet( + getfield(bs, 'stretch'), 0, db, da)) + setfield(bs, 'shrink', -blend_diffmet( + -getfield(bs, 'shrink'), 0, db, da)) node_free(ga) return gb end end end -local function calc_ja_ja_glue() - local qm, pm = Nq.met, Np.met - if (qm.char_type==pm.char_type) and (qm.var==pm.var) then - return new_jfm_glue(qm, Nq.class, Np.class) - else - local npn, nqn = Np.nuc, Nq.nuc - local gb, db = new_jfm_glue(qm, Nq.class, - slow_find_char_class(Np.char, - qm, getchar(npn))) - local ga, da = new_jfm_glue(pm, - slow_find_char_class(Nq.char, - pm, getchar(nqn)), - Np.class) - return calc_ja_ja_aux(gb, ga, db, da); +local null_skip_table = {0, 0, 0} +-- get kanjiskip +local get_kanjiskip, kanjiskip_jfm_flag +local calc_ja_ja_glue +do + local KANJI_SKIP = luatexja.icflag_table.KANJI_SKIP + local KANJI_SKIP_JFM = luatexja.icflag_table.KANJI_SKIP_JFM + + get_kanjiskip_low = function(flag, qm, bn, bp, bh) + if flag or (qm.with_kanjiskip and (bn or bp or bh)) then + if kanjiskip_jfm_flag then + local g = node_new(id_glue); + local gx = node_new(id_glue_spec); + setfield(gx, 'stretch_order', 0); setfield(gx, 'shrink_order', 0) + local bk = qm.kanjiskip or null_skip_table + setfield(gx, 'width', bn and (bn*bk[1]) or 0) + setfield(gx, 'stretch', bp and (bp*bk[2]) or 0) + setfield(gx, 'shrink', bh and (bh*bk[3]) or 0) + setfield(g, 'spec', gx) + set_attr(g, attr_icflag, KANJI_SKIP_JFM) + return g + elseif flag then + return node_copy(kanji_skip) + else + local g = node_new(id_glue); + local gx = node_new(id_glue_spec); + setfield(gx, 'stretch_order', 0); setfield(gx, 'shrink_order', 0) + local ks = getfield(kanji_skip, 'spec') + setfield(gx, 'width', bn and (bn*getfield(ks, 'width')) or 0) + setfield(gx, 'stretch', bp and (bp*getfield(ks, 'stretch')) or 0) + setfield(gx, 'shrink', bh and (bh*getfield(ks, 'shrink')) or 0) + setfield(g, 'spec', gx) + set_attr(g, attr_icflag, KANJI_SKIP_JFM) + return g + end + end + end + + get_kanjiskip = function() + if Np.auto_kspc or Nq.auto_kspc then + local pm, qm = Np.met, Nq.met + if (pm.char_type==qm.char_type) and (qm.var==pm.var) then + return get_kanjiskip_low(true, qm, 1, 1, 1) + else + local gb = get_kanjiskip_low(true, qm, 1, 1, 1) + local ga = get_kanjiskip_low(true, pm, 1, 1, 1) + return calc_ja_ja_aux(gb, ga, 0, 1) + end + else + local g = node_copy(zero_glue) + set_attr(g, attr_icflag, kanjiskip_jfm_flag and KANJI_SKIP_JFM or KANJI_SKIP) + return g + end + end + + calc_ja_ja_glue = function () + local qm, pm = Nq.met, Np.met + local qmc, pmc = qm.char_type, pm.char_type + if (qmc==pmc) and (qm.var==pm.var) then + local g, _, kn, kp, kh = new_jfm_glue(qmc, Nq.class, Np.class) + return g, (Np.auto_kspc or Nq.auto_kspc) and get_kanjiskip_low(false, qm, kn, kp, kh) + else + local npn, nqn = Np.nuc, Nq.nuc + local gb, db, bn, bp, bh + = new_jfm_glue(qmc, Nq.class, + slow_find_char_class(Np.char, + qm, getchar(npn))) + local ga, da, an, ap, ah + = new_jfm_glue(pmc, + slow_find_char_class(Nq.char, + pm, getchar(nqn)), + Np.class) + local g = calc_ja_ja_aux(gb, ga, db, da) + local k + if (pmc==qmc) and (qm.var==pm.var) then + gb = get_kanjiskip_low(false, qm, bn, bp, bh) + ga = get_kanjiskip_low(false, pm, an, ap, ah) + k = calc_ja_ja_aux(gb, ga, db, da) + end + return g, k + end end end -------------------- 和欧文間空白量の決定 -- get xkanjiskip -local get_xkanjiskip +local get_xkanjiskip, xkanjiskip_jfm_flag local get_xkanjiskip_normal, get_xkanjiskip_jfm do local XKANJI_SKIP = luatexja.icflag_table.XKANJI_SKIP local XKANJI_SKIP_JFM = luatexja.icflag_table.XKANJI_SKIP_JFM - get_xkanjiskip_normal = function (Nn) - if (Nq.xspc>=2) and (Np.xspc%2==1) and (Nq.auto_xspc or Np.auto_xspc) then - return node_copy(xkanji_skip) - else - local g = node_copy(zero_glue) - set_attr(g, attr_icflag, XKANJI_SKIP) - return g + + get_xkanjiskip_low = function(flag, qm, bn, bp, bh) + if flag or (qm.with_kanjiskip and (bn or bp or bh)) then + if xkanjiskip_jfm_flag then + local g = node_new(id_glue); + local gx = node_new(id_glue_spec); + setfield(gx, 'stretch_order', 0); setfield(gx, 'shrink_order', 0) + local bk = qm.xkanjiskip or null_skip_table + setfield(gx, 'width', bn and bk[1] or 0) + setfield(gx, 'stretch', bp and bk[2] or 0) + setfield(gx, 'shrink', bh and bk[3] or 0) + setfield(g, 'spec', gx) + set_attr(g, attr_icflag, XKANJI_SKIP_JFM) + return g + elseif flag then + return node_copy(xkanji_skip) + else + local g = node_new(id_glue); + local gx = node_new(id_glue_spec); + setfield(gx, 'stretch_order', 0); setfield(gx, 'shrink_order', 0) + local ks = getfield(xkanji_skip, 'spec') + setfield(gx, 'width', bn and getfield(ks, 'width') or 0) + setfield(gx, 'stretch', bp and getfield(ks, 'stretch') or 0) + setfield(gx, 'shrink', bh and getfield(ks, 'shrink') or 0) + setfield(g, 'spec', gx) + set_attr(g, attr_icflag, XKANJI_SKIP_JFM) + return g + end end end - get_xkanjiskip_jfm = function (Nn) - local g + + get_xkanjiskip = function(Nn) if (Nq.xspc>=2) and (Np.xspc%2==1) and (Nq.auto_xspc or Np.auto_xspc) then - g = node_new(id_glue) - local gx = node_new(id_glue_spec); - setfield(gx, 'stretch_order', 0); setfield(gx, 'shrink_order', 0) - local bk = Nn.met.xkanjiskip or null_skip_table - setfield(gx, 'width', bk[1]) - setfield(gx, 'stretch', bk[2]) - setfield(gx, 'shrink', bk[3]) - setfield(g, 'spec', gx) + return get_xkanjiskip_low(true, Nn.met, 1, 1, 1) else - g = node_copy(zero_glue) + local g = node_copy(zero_glue) + set_attr(g, attr_icflag, xkanjiskip_jfm_flag and XKANJI_SKIP_JFM or XKANJI_SKIP) + return g end - set_attr(g, attr_icflag, XKANJI_SKIP_JFM) - return g end end -------------------- 隣接した「塊」間の処理 -local function get_OA_skip() +local function get_OA_skip(is_kanji) local pm = Np.met - return new_jfm_glue(pm, - fast_find_char_class((Nq.id == id_math and -1 or 'jcharbdd'), pm), Np.class) + local g, _, kn, kp, kh = new_jfm_glue( + pm.char_type, + fast_find_char_class((Nq.id == id_math and -1 or 'jcharbdd'), pm), + Np.class) + local k + if is_kanji==0 then + k = (Np.auto_kspc or Nq.auto_kspc) and get_kanjiskip_low(false, pm, kn, kp, kh) + elseif is_kanji==1 then + k = ((Nq.xspc>=2) and (Np.xspc%2==1) and (Nq.auto_xspc or Np.auto_xspc)) + and get_xkanjiskip_low(false, pm, kn, kp, kh) + end + return g, k end -local function get_OB_skip() +local function get_OB_skip(is_kanji) local qm = Nq.met - return new_jfm_glue(qm, Nq.class, - fast_find_char_class((Np.id == id_math and -1 or'jcharbdd'), qm)) + local g, _, kn, kp, kh = new_jfm_glue( + qm.char_type, Nq.class, + fast_find_char_class((Np.id == id_math and -1 or'jcharbdd'), qm)) + local k + if is_kanji==0 then + k = (Np.auto_kspc or Nq.auto_kspc) and get_kanjiskip_low(false, qm, kn, kp, kh) + elseif is_kanji==1 then + k = ((Nq.xspc>=2) and (Np.xspc%2==1) and (Nq.auto_xspc or Np.auto_xspc)) + and get_xkanjiskip_low(false, qm, kn, kp, kh) + end + return g, k end -- (anything) .. jachar local function handle_np_jachar(mode) local qid = Nq.id if qid==id_jglyph or ((qid==id_pbox or qid==id_pbox_w) and Nq.met) then - local g = non_ihb_flag and calc_ja_ja_glue() or get_kanjiskip() -- M->K - handle_penalty_normal(Nq.post, Np.pre, g); real_insert(g) + local g, k + if non_ihb_flag then g, k = calc_ja_ja_glue() end -- M->K + if not g then g = get_kanjiskip() end + handle_penalty_normal(Nq.post, Np.pre, g); + real_insert(g); real_insert(k) elseif Nq.met then -- qid==id_hlist - local g = non_ihb_flag and get_OA_skip() or get_kanjiskip() -- O_A->K - handle_penalty_normal(0, Np.pre, g); real_insert(g) + local g, k + if non_ihb_flag then g, k = get_OA_skip(0) end -- O_A->K + if not g then g = get_kanjiskip() end + handle_penalty_normal(0, Np.pre, g); real_insert(g); real_insert(k) elseif Nq.pre then - local g = non_ihb_flag and get_OA_skip() or get_xkanjiskip(Np) -- O_A->X - handle_penalty_normal((qid==id_hlist and 0 or Nq.post), Np.pre, g); real_insert(g) + local g, k + if non_ihb_flag then g, k = get_OA_skip(1) end -- O_A->X + if not g then g = get_xkanjiskip(Np) end + handle_penalty_normal((qid==id_hlist and 0 or Nq.post), Np.pre, g); + real_insert(g); real_insert(k) else - local g = non_ihb_flag and get_OA_skip() -- O_A + local g = non_ihb_flag and (get_OA_skip()) -- O_A if qid==id_glue then handle_penalty_normal(0, Np.pre, g) elseif qid==id_kern then handle_penalty_suppress(0, Np.pre, g) else handle_penalty_always(0, Np.pre, g) @@ -913,10 +984,10 @@ end -- jachar .. (anything) local function handle_nq_jachar() if Np.pre then - local g = non_ihb_flag and get_OB_skip() or get_xkanjiskip(Nq) -- O_B->X + local g = non_ihb_flag and get_OB_skip(1) or get_xkanjiskip(Nq) -- O_B->X handle_penalty_normal(Nq.post, (Np.id==id_hlist and 0 or Np.pre), g); real_insert(g) else - local g =non_ihb_flag and get_OB_skip() -- O_B + local g =non_ihb_flag and (get_OB_skip()) -- O_B if Np.id==id_glue then handle_penalty_normal(Nq.post, 0, g) elseif Np.id==id_kern then handle_penalty_suppress(Nq.post, 0, g) else handle_penalty_always(Nq.post, 0, g) @@ -929,7 +1000,7 @@ end local function handle_np_ja_hlist() local qid = Nq.id if qid==id_jglyph or ((qid==id_pbox or Nq.id == id_pbox_w) and Nq.met) then - local g = non_ihb_flag and get_OB_skip() or get_kanjiskip() -- O_B->K + local g = non_ihb_flag and get_OB_skip(0) or get_kanjiskip() -- O_B->K handle_penalty_normal(Nq.post, 0, g); real_insert(g) elseif Nq.met then -- Nq.id==id_hlist local g = get_kanjiskip() -- K @@ -987,7 +1058,7 @@ local function handle_list_tail(mode) -- the current list is the contents of a hbox local npi, pm = Np.id, Np.met if npi == id_jglyph or (npi==id_pbox and pm) then - local g = new_jfm_glue(pm, Np.class, fast_find_char_class('boxbdd', pm)) + local g = new_jfm_glue(pm.char_type, Np.class, fast_find_char_class('boxbdd', pm)) if g then set_attr(g, attr_icflag, BOXBDD) head = insert_after(head, Np.last, g) @@ -1001,7 +1072,7 @@ local function handle_list_head(par_indented) local npi, pm = Np.id, Np.met if npi == id_jglyph or (npi==id_pbox and pm) then if non_ihb_flag then - local g = new_jfm_glue(pm, fast_find_char_class(par_indented, pm), Np.class) + local g = new_jfm_glue(pm.char_type, fast_find_char_class(par_indented, pm), Np.class) if g then set_attr(g, attr_icflag, BOXBDD) if getid(g)==id_glue and #Bp==0 then @@ -1054,16 +1125,14 @@ do kanji_skip = node_new(id_glue); set_attr(kanji_skip, attr_icflag, KANJI_SKIP) local s = skip_table_to_spec(KSK) setfield(kanji_skip, 'spec', s) - get_kanjiskip = (getfield(s, 'width') == 1073741823) - and get_kanjiskip_jfm or get_kanjiskip_normal + kanjiskip_jfm_flag = (getfield(s, 'width') == 1073741823) end do xkanji_skip = node_new(id_glue); set_attr(xkanji_skip, attr_icflag, XKANJI_SKIP) local s = skip_table_to_spec(XSK) setfield(xkanji_skip, 'spec', s) - get_xkanjiskip = (getfield(s, 'width') == 1073741823) - and get_xkanjiskip_jfm or get_xkanjiskip_normal + xkanjiskip_jfm_flag = (getfield(s, 'width') == 1073741823) end if mode then @@ -1088,7 +1157,8 @@ local ensure_tex_attr = ltjb.ensure_tex_attr local function cleanup(mode, TEMP) -- adjust attr_icflag for avoiding error if tex.getattribute(attr_icflag)~=0 then ensure_tex_attr(attr_icflag, 0) end - node_free(kanji_skip); node_free(xkanji_skip); node_free(TEMP) + node_free(kanji_skip); + node_free(xkanji_skip); node_free(TEMP) if mode then local h = node_next(head) |