tools: add vim snippet

Signed-off-by: David Lamparter <equinox@diac24.net>

tools/frr.vim

@@ -0,0 +1,36 @@
+" settings & syntax hilighting for FRR codebase
+" 2019 by David Lamparter, placed in public domain
+
+let c_gnu=1
+
+function! CStyleFRR()
+	syn clear	cFormat
+	syn match	cFormat		display "%\(\d\+\$\)\=[-+' #0*]*\(\d*\|\*\|\*\d\+\$\)\(\.\(\d*\|\*\|\*\d\+\$\)\)\=\([hlLjzt]\|ll\|hh\)\=\([aAbiuoxXDOUfFeEgGcCsSn]\|[pd]\([A-Z][A-Z0-9]*[a-z]*\|\)\|\[\^\=.[^]]*\]\)" contained
+	syn match	cFormat		display "%%" contained
+
+	syn keyword	cIterator	frr_each frr_each_safe frr_each_from
+	syn keyword	cMacroOp	offsetof container_of container_of_null array_size
+
+	syn keyword	cStorageClass	atomic
+	syn keyword	cFormatConst	PRId64	PRIu64	PRIx64
+	syn keyword	cFormatConst	PRId32	PRIu32	PRIx32
+	syn keyword	cFormatConst	PRId16	PRIu16	PRIx16
+	syn keyword	cFormatConst	PRId8	PRIu8	PRIx8
+
+	" you can unlink these by just giving them their own hilighting / color
+	hi link cFormatConst	cFormat
+	hi link cIterator	cRepeat
+	hi link cMacroOp	cOperator
+
+	" indentation
+	setlocal cindent
+	setlocal cinoptions=:0,(0,u4,w1,W8
+	setlocal shiftwidth=8
+	setlocal softtabstop=0
+	setlocal textwidth=0
+	setlocal fo=croql
+	setlocal noet
+endfunction
+
+" auto-apply the above based on path rules
+"autocmd BufRead,BufNewFile /home/.../frr/*.[ch] call CStyleFRR()