needs tests/harness text/diff
testbegin

\test max[]=
create a1 map< , 1 2 3 4 5
create a2 map< , 1 2 9 4 5

a1 5 a2 5 max[]= 2 #eq
a1 5 a2 1 max[]= 1 #eq
a1 0 a2 5 max[]= 0 #eq

\test lcs
create a1 map< , 1 2 3 4 5
create a2 map< , 1 2 1 2 3 4 1 2 3

a1 5 a2 9 lcs 4 #eq 2 #eq

\test diffcrcs[]
: #hunk= ( lidx ridx delcnt addcnt lidx ridx delcnt addcnt -- )
  5 roll #eq 4 roll #eq rot #eq #eq ;

create a1 map< , 1 2 3 4 5
create a2 map< , 1 3 4 6 7 5
a1 5 a2 6 diffcrcs[] 2 #eq 4 3 0 2 #hunk= 1 1 1 0 #hunk=

\test diffcrcs[] compound deletions
create a1 map< , 1 2 3 4 5
create a2 map< , 1 2 5
a1 5 a2 3 diffcrcs[] 1 #eq 2 2 2 0 #hunk=

\test diffcrcs[] replacement
create a1 map< , 1 2 3 4 5
create a2 map< , 1 2 8 4 5
a1 5 a2 5 diffcrcs[] 1 #eq 2 2 1 1 #hunk=

\test diffcrcs[] tail replacement
create a1 map< , 1 2 3
create a2 map< , 1 2 4
a1 3 a2 3 diffcrcs[] 1 #eq 2 2 1 1 #hunk=

\test diff[]
: #hunk= ( hunk lidx ridx delcnt addcnt -- )
  5 roll 16 + 4 0 do 4- tuck @ #eq loop drop ;

"abc\ndef\nghi" c@+
"abc\nYYY\ndef\nXXX" c@+ diff[] 2 #eq
  dup 1 1 0 1 #hunk= 16 + 2 3 1 1 #hunk=

\test skipline
"ghi" "abc\ndef\nghi" c@+ skipline skipline #s[]=

\test .diff[]
\ no assert, just print the diff
"abc\ndef\nghi" c@+
"abc\nYYY\ndef\nXXX" c@+ .diff[]

testend