" For version 6.x: Quit when this syntax file was already loaded
if v:version < 600
syntax clear
set iskeyword+=-,*,#,+,_,/
elseif exists("b:current_syntax")
finish
else
setlocal iskeyword+=-,*,#,+,_,/
endif
" NATURAL is case insensitive
syntax case ignore
" preprocessor
syn keyword naturalInclude include nextgroup=naturalObjName skipwhite
" define data
syn keyword naturalKeyword define data end-define
syn keyword naturalKeyword independent global parameter local redefine view
syn keyword naturalKeyword const[ant] init initial
" loops
syn keyword naturalLoop read end-read end-work find end-find histogram end-histogram
syn keyword naturalLoop end-all sort end-sort sorted descending ascending
syn keyword naturalRepeat repeat end-repeat while until for step end-for
syn keyword naturalKeyword in file with field starting from ending at thru by isn where
syn keyword naturalError on error end-error
syn keyword naturalKeyword accept reject end-enddata number unique retain as release
syn keyword naturalKeyword start end-start break end-break physical page top sequence
syn keyword naturalKeyword end-toppage end-endpage end-endfile before processing
syn keyword naturalKeyword end-before
" conditionals
syn keyword naturalConditional if then else end-if end-norec
syn keyword naturalConditional decide end-decide value when condition none any
" assignment / calculation
syn keyword naturalKeyword reset assign move left right justified compress to into edited
syn keyword naturalKeyword add subtract multiply divide compute name
syn keyword naturalKeyword all giving remainder rounded leaving space
syn keyword naturalKeyword examine full replace giving separate delimiter modified
syn keyword naturalKeyword suspend identical suppress
" program flow
syn keyword naturalFlow callnat fetch return enter escape bottom top stack formatted
syn keyword naturalFlow command call
syn keyword naturalflow end-subroutine routine
" file operations
syn keyword naturalKeyword update store get delete end transaction work once close
" other keywords
syn keyword naturalKeyword first every of no record[s] found ignore immediate
syn keyword naturalKeyword set settime key control stop terminate
" in-/output
syn keyword naturalKeyword write display input reinput notitle nohdr map newpage mark
syn keyword naturalKeyword alarm text help eject index
syn keyword naturalKeyword format printer skip lines
" functions
syn keyword naturalKeyword abs atn cos exp frac int log sgn sin sqrt tan val old
" report mode keywords
syn keyword naturalRMKeyword same loop obtain indexed do doend
" Subroutine name
syn keyword naturalFlow perform subroutine nextgroup=naturalFunction skipwhite
syn match naturalFunction "\<[a-z][-_a-z0-9]*\>"
syn keyword naturalFlow using nextgroup=naturalKeyword,naturalObjName skipwhite
syn match naturalObjName "\<[a-z][-_a-z0-9]\{,7}\>"
" Labels
syn match naturalLabel "\<[+#a-z][-_#a-z0-9]*\."
syn match naturalRef "\<[+#a-z][-_#a-z0-9]*\>\.\<[+#a-z][*]\=[-_#a-z0-9]*\>"
" System variables
syn match naturalSysVar "\<\*[a-z][-a-z0-9]*\>"
"integer number, or floating point number without a dot.
syn match naturalNumber "\<-\=\d\+\>"
"floating point number, with dot
syn match naturalNumber "\<-\=\d\+\.\d\+\>"
"floating point number, starting with a dot
syn match naturalNumber "\.\d\+"
" Formats in write statement
syn match naturalFormat "\<\d\+[TX]\>"
" String and Character contstants
syn match naturalString "H'\x\+'"
syn region naturalString start=+"+ end=+"+
syn region naturalString start=+'+ end=+'+
" Type definition
syn match naturalAttribute "\<[-a-z][a-z]=[-a-z0-9_\.,]\+\>"
syn match naturalType contained "\<[ABINP]\d\+\(,\d\+\)\=\>"
syn match naturalType contained "\<[CL]\>"
" "TODO" / other comments
syn keyword naturalTodo contained todo test
syn match naturalCommentMark contained "[a-z][^ \t/:|]*\(\s[^ \t/:'"|]\+\)*:\s"he=e-1
" comments
syn region naturalComment start="/\*" end="$" contains=naturalTodo,naturalLineRef,naturalCommentMark
syn region naturalComment start="^\*[\ \*]" end="$" contains=naturalTodo,naturalLineRef,naturalCommentMark
syn region naturalComment start="^\d\{4} \*[\ \*]"lc=5 end="$" contains=naturalTodo,naturalLineRef,naturalCommentMark
syn match naturalComment "^*$"
syn match naturalComment "^\d\{4} \*$"lc=5
" /* is legal syntax in parentheses e.g. "#ident(label./*)"
syn region naturalPComment contained start="/\*\s*[^),]" end="$" contains=naturalTodo,naturalLineRef,naturalCommentMark
" operators
syn keyword naturalOperator and or not eq ne gt lt ge le mask scan
" constants
syn keyword naturalBoolean true false
syn match naturalLineNo "^\d\{4}"
" identifiers
syn match naturalIdent "\<[+#a-z][-_#a-z0-9]*\>[^\.']"me=e-1
syn match naturalIdent "\<[+#a-z][-_#a-z0-9]*$"
syn match naturalLegalIdent "[+#a-z][-_#a-z0-9]*/[-_#a-z0-9]*"
" parentheses
syn region naturalPar matchgroup=naturalParGui start="(" end=")" contains=naturalLabel,naturalRef,naturalOperator,@naturalConstant,naturalType,naturalSysVar,naturalPar,naturalLineNo,naturalPComment
