diff --git a/runtime/syntax/vim.vim b/runtime/syntax/vim.vim
index 1ff7d71..eb24216 100644
--- a/runtime/syntax/vim.vim
+++ b/runtime/syntax/vim.vim
@@ -34,8 +34,8 @@
 " regular vim commands {{{2
 " GEN_SYN_VIM: vimCommand normal, START_STR='syn keyword vimCommand contained', END_STR='nextgroup=vimBang'
 syn keyword vimCommand contained abo[veleft] al[l] ar[gs] arga[dd] argd[elete] argdo argded[upe] arge[dit] argg[lobal] argl[ocal] argu[ment] as[cii] b[uffer] bN[ext] ba[ll] bad[d] balt bd[elete] bel[owright] bf[irst] bl[ast] bm[odified] bn[ext] bo[tright] bp[revious] br[ewind] brea[k] breaka[dd] breakd[el] breakl[ist] bro[wse] buffers bufd[o] bun[load] bw[ipeout] c[hange] cN[ext] cNf[ile] cabo[ve] cad[dbuffer] cadde[xpr] caddf[ile] caf[ter] cb[uffer] cbe[fore] cbel[ow] cbo[ttom] cc ccl[ose] cd cdo ce[nter] cex[pr] cf[ile] cfd[o] cfir[st] cg[etfile] cgetb[uffer] cgete[xpr] chd[ir] changes che[ckpath] checkt[ime] chi[story] cl[ist] cla[st] clo[se] cle[arjumps] cn[ext] cnew[er] cnf[ile] co[py] col[der] colo[rscheme] com[mand] comc[lear] comp[iler] con[tinue] conf[irm] nextgroup=vimBang
-syn keyword vimCommand contained cons[t] cope[n] cp[revious] cpf[ile] cq[uit] cr[ewind] cs[cope] cst[ag] cw[indow] d[elete] delm[arks] deb[ug] defc[ompile] defe[r] delf[unction] di[splay] dif[fupdate] diffg[et] diffo[ff] diffp[atch] diffpu[t] diffs[plit] difft[his] dig[raphs] disa[ssemble] dj[ump] dli[st] dr[op] ds[earch] dsp[lit] e[dit] ea[rlier] em[enu] endfo[r] endt[ry] endw[hile] ene[w] ev[al] ex exi[t] exu[sage] f[ile] files filet[ype] fin[d] fina[lly] fini[sh] fir[st] fix[del] fo[ld] foldc[lose] foldd[oopen] folddoc[losed] foldo[pen] g[lobal] go[to] gu[i] gv[im] h[elp] helpc[lose] helpf[ind] helpt[ags] ha[rdcopy] hi[ghlight] hid[e] his[tory] hor[izontal] ij[ump] il[ist] int[ro] ip[ut] is[earch] isp[lit] j[oin] ju[mps] k kee[pmarks] keepj[umps] keepp[atterns] nextgroup=vimBang
-syn keyword vimCommand contained keepa[lt] l[ist] lN[ext] lNf[ile] la[st] lab[ove] lan[guage] lad[dexpr] laddb[uffer] laddf[ile] laf[ter] lat[er] lb[uffer] lbe[fore] lbel[ow] lbo[ttom] lc[d] lch[dir] lcl[ose] lcs[cope] ld[o] le[ft] lefta[bove] lex[pr] leg[acy] lf[ile] lfd[o] lfir[st] lg[etfile] lgetb[uffer] lgete[xpr] lgr[ep] lgrepa[dd] lhi[story] ll lla[st] lli[st] lmak[e] lne[xt] lnew[er] lnf[ile] lo[adview] loc[kmarks] lockv[ar] lol[der] lop[en] lp[revious] lpf[ile] lr[ewind] lt[ag] lw[indow] ls m[ove] ma[rk] marks menut[ranslate] mes[sages] mk[exrc] mks[ession] mksp[ell] mkv[imrc] mkvie[w] mod[e] n[ext] nb[key] nbc[lose] nbs[tart] noa[utocmd] noh[lsearch] nos[wapfile] nu[mber] o[pen] ol[dfiles] on[ly] opt[ions] ow[nsyntax] p[rint] pa[ckadd] packl[oadall] pb[uffer] nextgroup=vimBang
+syn keyword vimCommand contained cons[t] cope[n] cp[revious] cpf[ile] cq[uit] cr[ewind] cs[cope] cst[ag] cw[indow] d[elete] delm[arks] deb[ug] defc[ompile] defe[r] delf[unction] di[splay] dif[fupdate] diffg[et] diffo[ff] diffp[atch] diffpu[t] diffs[plit] difft[his] dig[raphs] disa[ssemble] dj[ump] dli[st] dr[op] ds[earch] dsp[lit] e[dit] ea[rlier] em[enu] endfo[r] endt[ry] endw[hile] ene[w] ev[al] ex exi[t] exu[sage] f[ile] files filet[ype] fin[d] fina[lly] fini[sh] fir[st] fix[del] fo[ld] foldc[lose] foldd[oopen] folddoc[losed] foldo[pen] g[lobal] go[to] gu[i] gv[im] h[elp] helpc[lose] helpf[ind] helpt[ags] ha[rdcopy] hi[ghlight] hid[e] his[tory] hor[izontal] ij[ump] il[ist] int[ro] ip[ut] is[earch] isp[lit] j[oin] ju[mps] kee[pmarks] keepj[umps] keepp[atterns] nextgroup=vimBang
+syn keyword vimCommand contained keepa[lt] l[ist] lN[ext] lNf[ile] la[st] lab[ove] lan[guage] lad[dexpr] laddb[uffer] laddf[ile] laf[ter] lat[er] lb[uffer] lbe[fore] lbel[ow] lbo[ttom] lc[d] lch[dir] lcl[ose] lcs[cope] ld[o] le[ft] lefta[bove] lex[pr] leg[acy] lf[ile] lfd[o] lfir[st] lg[etfile] lgetb[uffer] lgete[xpr] lgr[ep] lgrepa[dd] lhi[story] ll lla[st] lli[st] lmak[e] lne[xt] lnew[er] lnf[ile] lo[adview] loc[kmarks] lockv[ar] lol[der] lop[en] lp[revious] lpf[ile] lr[ewind] lt[ag] lw[indow] ls m[ove] marks menut[ranslate] mes[sages] mk[exrc] mks[ession] mksp[ell] mkv[imrc] mkvie[w] mod[e] n[ext] nb[key] nbc[lose] nbs[tart] noa[utocmd] noh[lsearch] nos[wapfile] nu[mber] o[pen] ol[dfiles] on[ly] opt[ions] ow[nsyntax] p[rint] pa[ckadd] packl[oadall] pb[uffer] nextgroup=vimBang
 syn keyword vimCommand contained pc[lose] ped[it] po[p] pp[op] pre[serve] prev[ious] pro[mptfind] promptr[epl] prof[ile] profd[el] ps[earch] pt[ag] ptN[ext] ptf[irst] ptj[ump] ptl[ast] ptn[ext] ptp[revious] ptr[ewind] pts[elect] pu[t] pw[d] q[uit] quita[ll] qa[ll] r[ead] rec[over] red[o] redr[aw] redraws[tatus] redrawt[abline] redrawtabp[anel] reg[isters] res[ize] ret[ab] rew[ind] ri[ght] rightb[elow] ru[ntime] rub[y] rubyd[o] rubyf[ile] rund[o] rv[iminfo] sN[ext] sa[rgument] sal[l] san[dbox] sav[eas] sb[uffer] sbN[ext] sba[ll] sbf[irst] sbl[ast] sbm[odified] sbn[ext] sbp[revious] sbr[ewind] scr[iptnames] scripte[ncoding] scriptv[ersion] scs[cope] setf[iletype] sf[ind] sfir[st] sh[ell] sim[alt] sig[n] sil[ent] sla[st] sn[ext] so[urce] sp[lit] spe[llgood] spelld[ump] nextgroup=vimBang
 syn keyword vimCommand contained spelli[nfo] spellr[epall] spellra[re] spellu[ndo] spellw[rong] spr[evious] sre[wind] st[op] sta[g] star[tinsert] startg[replace] startr[eplace] stopi[nsert] stj[ump] sts[elect] sun[hide] sus[pend] sv[iew] sw[apname] synti[me] sync[bind] smi[le] t tN[ext] ta[g] tags tab tabc[lose] tabd[o] tabe[dit] tabf[ind] tabfir[st] tabm[ove] tabl[ast] tabn[ext] tabnew tabo[nly] tabp[revious] tabN[ext] tabr[ewind] tabs tc[d] tch[dir] te[aroff] ter[minal] tf[irst] tj[ump] tl[ast] tn[ext] to[pleft] tp[revious] tr[ewind] try ts[elect] u[ndo] undoj[oin] undol[ist] unh[ide] unlo[ckvar] uns[ilent] up[date] v[global] ve[rsion] verb[ose] vert[ical] vi[sual] vie[w] vim9[cmd] viu[sage] vne[w] vs[plit] w[rite] wN[ext] wa[ll] wi[nsize] winc[md] wind[o] winp[os] nextgroup=vimBang
 syn keyword vimCommand contained wn[ext] wp[revious] wq wqa[ll] wu[ndo] wv[iminfo] x[it] xa[ll] xr[estore] y[ank] z dl dell delel deletl deletel dp dep delp delep deletp deletep a i nextgroup=vimBang
@@ -286,7 +286,7 @@
 syn case match
 
 " All vimCommands are contained by vimIsCommand. {{{2
-syn cluster vimCmdList	contains=vimAbb,vimAddress,vimAutocmd,vimAugroup,vimBehave,vimCall,vimCatch,vimConst,vimDoautocmd,vimDebuggreedy,vimDef,vimDefFold,vimDelcommand,@vimEcho,vimElse,vimEnddef,vimEndfunction,vimEndif,vimExecute,vimIsCommand,vimExtCmd,vimExFilter,vimFor,vimFunction,vimFuncFold,vimGrep,vimGrepAdd,vimGlobal,vimHelpgrep,vimHighlight,vimImport,vimLet,vimLoadkeymap,vimLockvar,vimMake,vimMap,vimMark,vimMatch,vimNotFunc,vimNormal,vimRedir,vimSet,vimSleep,vimSort,vimSyntax,vimThrow,vimUnlet,vimUnlockvar,vimUnmap,vimUserCmd,vimVimgrep,vimVimgrepadd,vimMenu,vimMenutranslate,@vim9CmdList,@vimExUserCmdList,vimLua,vimMzScheme,vimPerl,vimPython,vimPython3,vimPythonX,vimRuby,vimTcl
+syn cluster vimCmdList	contains=vimAbb,vimAddress,vimAutocmd,vimAugroup,vimBehave,vimCall,vimCatch,vimConst,vimDoautocmd,vimDebuggreedy,vimDef,vimDefFold,vimDelcommand,@vimEcho,vimElse,vimEnddef,vimEndfunction,vimEndif,vimExecute,vimIsCommand,vimExtCmd,vimExFilter,vimExMark,vimFor,vimFunction,vimFuncFold,vimGrep,vimGrepAdd,vimGlobal,vimHelpgrep,vimHighlight,vimImport,vimLet,vimLoadkeymap,vimLockvar,vimMake,vimMap,vimMark,vimMatch,vimNotFunc,vimNormal,vimRedir,vimSet,vimSleep,vimSort,vimSyntax,vimThrow,vimUnlet,vimUnlockvar,vimUnmap,vimUserCmd,vimVimgrep,vimVimgrepadd,vimMenu,vimMenutranslate,@vim9CmdList,@vimExUserCmdList,vimLua,vimMzScheme,vimPerl,vimPython,vimPython3,vimPythonX,vimRuby,vimTcl
 syn cluster vim9CmdList	contains=vim9Abstract,vim9Class,vim9Const,vim9Enum,vim9Export,vim9Final,vim9For,vim9Interface,vim9Type,vim9Var
 syn match vimCmdSep	"\\\@1<!|"	skipwhite nextgroup=@vimCmdList,vimSubst1,vimFunc
 syn match vimCmdSep	":\+"	skipwhite nextgroup=@vimCmdList,vimSubst1
@@ -901,10 +901,16 @@
 syn cluster	vimSubstList	contains=vimPatSep,vimPatRegion,vimPatSepErr,vimSubstTwoBS,vimSubstRange,vimNotation
 syn cluster	vimSubstRepList	contains=vimSubstSubstr,vimSubstTwoBS,vimNotation
 syn cluster	vimSubstList	add=vimCollection
-syn match	vimSubst	"^\s*\%(s\%[ubstitute]\|sm\%[agic]\|sno\%[magic]\)\>"			skipwhite nextgroup=vimSubstPat
-syn match	vimSubst	"^\s*\%(s\%[ubstitute]\|sm\%[agic]\|sno\%[magic]\)[_#]\@="		skipwhite nextgroup=vimSubstPat
-syn match	vimSubst1	contained	"\%(s\%[ubstitute]\|sm\%[agic]\>\|sno\%[magic]\)\>"		skipwhite nextgroup=vimSubstPat
+syn match	vimSubst		"^\s*\%(s\%[ubstitute]\|sm\%[agic]\|sno\%[magic]\)\>"		skipwhite nextgroup=vimSubstPat,vimSubstFlags,vimSubstCount
+syn match	vimSubst		"^\s*\%(s\%[ubstitute]\|sm\%[agic]\|sno\%[magic]\)[_#]\@="	skipwhite nextgroup=vimSubstPat
+syn match	vimSubst		"^\s*\%(s\%[ubstitute]\|sm\%[agic]\|sno\%[magic]\)\%(\d\+\)\@="	skipwhite nextgroup=vimSubstCount
+syn match	vimSubst1	contained	"\%(s\%[ubstitute]\|sm\%[agic]\>\|sno\%[magic]\)\>"		skipwhite nextgroup=vimSubstPat,vimSubstFlags,vimSubstCount
 syn match	vimSubst1	contained	"\%(s\%[ubstitute]\|sm\%[agic]\>\|sno\%[magic]\)[_#]\@="	skipwhite nextgroup=vimSubstPat
+syn match	vimSubst1	contained	"\%(s\%[ubstitute]\|sm\%[agic]\>\|sno\%[magic]\)\%(\d\+\)\@="	skipwhite nextgroup=vimSubstCount
+syn match	vimSubstFlagErr	contained	"[^< \t\r|]\+" contains=vimSubstFlags
+" & and # after :s are always pattern delimiters not flags
+syn match	vimSubstFlags	contained	"[&cegiIlnpr#]\+"	skipwhite nextgroup=vimSubstCount
+syn match	vimSubstCount	contained	"\d\+\>"
 " TODO: Vim9 illegal separators for abbreviated :s form are [-.:], :su\%[...] required
 "     : # is allowed but "not recommended" (see :h pattern-delimiter)
 syn region	vimSubstPat	contained	matchgroup=vimSubstDelim start="\z([!#$%&'()*+,-./:;<=>?@[\]^_`{}~]\)"rs=s+1 skip="\\\\\|\\\z1" end="\z1"re=e-1,me=e-1	contains=@vimSubstList	nextgroup=vimSubstRep4	oneline
@@ -914,13 +920,41 @@
 syn match	vimCollClass	contained 	transparent	"\%#=1\[:\(alnum\|alpha\|blank\|cntrl\|digit\|graph\|lower\|print\|punct\|space\|upper\|xdigit\|retu\%[rn]\|tab\|escape\|backspace\):\]"
 syn match	vimSubstSubstr	contained	"\\z\=\d"
 syn match	vimSubstTwoBS	contained	"\\\\"
-syn match	vimSubstFlagErr	contained	"[^< \t\r|]\+" contains=vimSubstFlags
-syn match	vimSubstFlags	contained	"[&cegiIlnpr#]\+"
+
+" TODO: flags, unlike count, must follow immediately
+"     : distinguish from with Vim9 &var
+" syn match	vimSubst		"^\s*\zs&&\="	skipwhite nextgroup=vimSubstFlags,vimSubstCount
+" syn match	vimSubst		"^\s*\zs\~&\="	skipwhite nextgroup=vimSubstFlags,vimSubstCount
+" syn match	vimSubst1	contained	"&&\="	skipwhite nextgroup=vimSubstFlags,vimSubstCount
+" syn match	vimSubst1	contained	"\~&\="	skipwhite nextgroup=vimSubstFlags,vimSubstCount
+
+" two and three letter variants (matched as :s + flags, count may follow immediately)
+syn match	vimSubst		"^\s*\zssc[egiIlnp]\=\a\@!"	skipwhite nextgroup=vimSubstCount	contains=vimSubstFlags
+syn match	vimSubst		"^\s*\zssg[ceiIlnpr]\=\a\@!"	skipwhite nextgroup=vimSubstCount	contains=vimSubstFlags
+syn match	vimSubst		"^\s*\zssi[ceInpr]\=\a\@!"	skipwhite nextgroup=vimSubstCount	contains=vimSubstFlags
+syn match	vimSubst		"^\s*\zssI[ceginplr]\=\a\@!"	skipwhite nextgroup=vimSubstCount	contains=vimSubstFlags
+syn match	vimSubst		"^\s*\zssr[cgiInplr]\=\a\@!"	skipwhite nextgroup=vimSubstCount	contains=vimSubstFlags
+
+syn match	vimSubst1	contained	"\<sc[egiIlnp]\=\a\@!"	skipwhite nextgroup=vimSubstCount	contains=vimSubstFlags
+syn match	vimSubst1	contained	"\<sg[ceiIlnpr]\=\a\@!"	skipwhite nextgroup=vimSubstCount	contains=vimSubstFlags
+syn match	vimSubst1	contained	"\<si[ceInpr]\=\a\@!"	skipwhite nextgroup=vimSubstCount	contains=vimSubstFlags
+syn match	vimSubst1	contained	"\<sI[ceginplr]\=\a\@!"	skipwhite nextgroup=vimSubstCount	contains=vimSubstFlags
+syn match	vimSubst1	contained	"\<sr[cgiInplr]\=\a\@!"	skipwhite nextgroup=vimSubstCount	contains=vimSubstFlags
 
 " Vi compatibility
 syn match	vimSubstDelim	contained	"\\"
 syn match	vimSubstPat	contained	"\\\ze[/?&]" contains=vimSubstDelim nextgroup=vimSubstRep4
 
+" Mark: {{{2
+" ====
+VimL syn match	vimExMark	"\<k\%([a-zA-Z0-9]\>\|[[\]<>'`]\)\@="         nextgroup=@vimMarkArg
+VimL syn match	vimExMark	"\<k\>"	      	skipwhite nextgroup=@vimMarkArg
+syn match	vimExMark	"\<mark\>"	      	skipwhite nextgroup=@vimMarkArg
+
+syn match	vimMarkArg	contained	"[a-zA-Z]\>\|[[\]<>'`]"	skipwhite nextgroup=vimCmdSep,vimComment
+syn match	vimMarkArgError	contained	"["^.(){}0-9]"
+syn cluster	vimMarkArg	contains=vimMarkArg,vimMarkArgError
+
 " Marks, Registers, Addresses, Filters: {{{2
 syn match	vimMark	"'[a-zA-Z0-9]\ze[-+,!]"	nextgroup=vimFilter,vimMarkNumber,vimSubst1
 syn match	vimMark	"'[[\]{}()<>]\ze[-+,!]"	nextgroup=vimFilter,vimMarkNumber,vimSubst1
@@ -2002,6 +2036,7 @@
   hi def link vimHiCtermError	vimError
   hi def link vimHiKeyError	vimError
   hi def link vimMapModErr	vimError
+  hi def link vimMarkArgError	vimError
   hi def link vimShebangError	vimError
   hi def link vimSortOptionsError	Error
   hi def link vimSubstFlagErr	vimError
@@ -2071,6 +2106,7 @@
  hi def link vimEscape	Special
  hi def link vimExFilter	vimCommand
  hi def link vimExFilterBang	vimCommand
+ hi def link vimExMark	vimCommand
  hi def link vimFBVar	vimVar
  hi def link vimFgBgAttrib	vimHiAttrib
  hi def link vimFuncEcho	vimCommand
@@ -2222,6 +2258,7 @@
  hi def link vimStringEnd	vimString
  hi def link vimStringInterpolationBrace	vimEscape
  hi def link vimSubst1	vimSubst
+ hi def link vimSubstCount	Number
  hi def link vimSubstDelim	Delimiter
  hi def link vimSubstFlags	Special
  hi def link vimSubstSubstr	SpecialChar