" Declarations, definitions and blocks
syn region NITModuleDecl matchgroup=NITDefine start="\<\(import\|module\|package\)\>\s*" matchgroup=NONE end="\ze\(\s\|:\|(\|$\)" oneline
-syn region NITClassBlock matchgroup=NITDefine start="\<\(class\|enum\|universal\|interface\)\>" matchgroup=NITDefine end="\<end\>" contains=ALL fold
+syn region NITClassBlock matchgroup=NITDefine start="\<\(class\|enum\|universal\|interface\|extern\)\>" matchgroup=NITDefine end="\<end\>" contains=ALL fold
syn region NITFunctionDecl matchgroup=NITDefine start="\<fun\>\s*" matchgroup=NONE end="\ze\(\<do\>\|\s\|:\|(\|$\)" oneline
syn region NITTypeDecl matchgroup=NITDefine start="\<type\>\s*" matchgroup=NONE end="\ze\(\<do\>\|\s\|:\|(\|$\)" oneline contained containedin=NITClassBlock
syn region NITAttrDecl matchgroup=NITDefine start="\<var\>\s*\ze_" matchgroup=NONE end="\ze\(\<do\>\|\s\|:\|(\|$\)" oneline contained containedin=NITClassBlock
syn match NITComment "#.*" contains=NITTodo
" Keywords
-syn keyword NITKeyword is abstract intern extern new
+syn keyword NITKeyword is abstract intern new
syn keyword NITDefine private public protected intrude readable writable redef
syn keyword NITControl if while for assert and or in as isa once break continue return abort
syn keyword NITClass nullable