Tests for regexp with multi-byte encoding and various magic settings.
Test matchstr() with a count and multi-byte chars.
See test44 for exactly the same test with re=1.

STARTTEST
:so mbyte.vim
:set nocompatible encoding=utf-8 termencoding=latin1 viminfo+=nviminfo
:set re=2
/^1
/a*b\{2}c\+/e
x/\Md\*e\{2}f\+/e
x:set nomagic
/g\*h\{2}i\+/e
x/\mj*k\{2}l\+/e
x/\vm*n{2}o+/e
x/\V^aa$
x:set magic
/\v(a)(b)\2\1\1/e
x/\V[ab]\(\[xy]\)\1
x:" Now search for multi-byte without composing char
/ม
x:" Now search for multi-byte with composing char
/ม่
x:" find word by change of word class
/ち\<カヨ\>は
x:" Test \%u, [\u] and friends
/\%u20ac
x/[\u4f7f\u5929]\+
x/\%U12345678
x/[\U1234abcd\u1234\uabcd]
x/\%d21879b
x/ [[=A=]]* [[=B=]]* [[=C=]]* [[=D=]]* [[=E=]]* [[=F=]]* [[=G=]]* [[=H=]]* [[=I=]]* [[=J=]]* [[=K=]]* [[=L=]]* [[=M=]]* [[=N=]]* [[=O=]]* [[=P=]]* [[=Q=]]* [[=R=]]* [[=S=]]* [[=T=]]* [[=U=]]* [[=V=]]* [[=W=]]* [[=X=]]* [[=Y=]]* [[=Z=]]*/e
x/ [[=a=]]* [[=b=]]* [[=c=]]* [[=d=]]* [[=e=]]* [[=f=]]* [[=g=]]* [[=h=]]* [[=i=]]* [[=j=]]* [[=k=]]* [[=l=]]* [[=m=]]* [[=n=]]* [[=o=]]* [[=p=]]* [[=q=]]* [[=r=]]* [[=s=]]* [[=t=]]* [[=u=]]* [[=v=]]* [[=w=]]* [[=x=]]* [[=y=]]* [[=z=]]*/e
x:" Test backwards search from a multi-byte char
/x
x?.
x:let @w=':%s#comb[i]nations#œ̄ṣ́m̥̄ᾱ̆́#g'
:@w
:?^1?,$w! test.out
:e! test.out
G:put =matchstr(\"אבגד\", \".\", 0, 2) " ב
:put =matchstr(\"אבגד\", \"..\", 0, 2) " בג
:put =matchstr(\"אבגד\", \".\", 0, 0) " א
:put =matchstr(\"אבגד\", \".\", 4, -1) " ג
:w!
:qa!
ENDTEST

1 a aa abb abbccc
2 d dd dee deefff
3 g gg ghh ghhiii
4 j jj jkk jkklll
5 m mm mnn mnnooo
6 x ^aa$ x
7 (a)(b) abbaa
8 axx [ab]xx
9 หม่x อมx
a อมx หม่x
b ちカヨは
c x ¬€x
d 天使x
e ������y
f ������z
g a啷bb
h AÀÁÂÃÄÅĀĂĄǍǞǠẢ BḂḆ CÇĆĈĊČ DĎĐḊḎḐ EÈÉÊËĒĔĖĘĚẺẼ FḞ GĜĞĠĢǤǦǴḠ HĤĦḢḦḨ IÌÍÎÏĨĪĬĮİǏỈ JĴ KĶǨḰḴ LĹĻĽĿŁḺ MḾṀ NÑŃŅŇṄṈ OÒÓÔÕÖØŌŎŐƠǑǪǬỎ PṔṖ Q RŔŖŘṘṞ SŚŜŞŠṠ TŢŤŦṪṮ UÙÚÛÜŨŪŬŮŰŲƯǓỦ VṼ WŴẀẂẄẆ XẊẌ YÝŶŸẎỲỶỸ ZŹŻŽƵẐẔ
i aàáâãäåāăąǎǟǡả bḃḇ cçćĉċč dďđḋḏḑ eèéêëēĕėęěẻẽ fḟ gĝğġģǥǧǵḡ hĥħḣḧḩẖ iìíîïĩīĭįǐỉ jĵǰ kķǩḱḵ lĺļľŀłḻ mḿṁ nñńņňʼnṅṉ oòóôõöøōŏőơǒǫǭỏ pṕṗ q rŕŗřṙṟ sśŝşšṡ tţťŧṫṯẗ uùúûüũūŭůűųưǔủ vṽ wŵẁẃẅẇẘ xẋẍ yýÿŷẏẙỳỷỹ zźżžƶẑẕ
j 0123❤x
k combinations