[MLIR] Fix MLIR vim syntax file

[sgrechanik]

Summary

This commit fixes several things in the MLIR vim syntax file:

• Spell checking is now on by default only in comments.
• '#' now starts an identifier instead of starting an outline attribute declaration, which fixes coloring the rest of the line as a preprocessor directive when there is a '#' in the middle.
• '!' and '^' -prefixed identifiers are now colored as types and labels.

[bondhugula]

Thanks for this. Can you also add the bullets from the commit summary as comments in the syntax file itself?

[sgrechanik]

Added comments

[bondhugula]

Won't this change the color for the attribute definitions? (from PreProc to Identifier)

[sgrechanik]

Yes, it will. I can separate it into a separate group if you want it to stand out more.

[sgrechanik]

Added separate groups for different kinds of identifiers, they will have different colors now.

[bondhugula]

LGTM.

mlir/utils/vim/syntax/mlir.vim

 syn match   mlirNumber /-\?\<\d\+\>/
 " Match numbers even in shaped types.
 syn match   mlirNumber /-\?\<\d\+\ze\s*x/
 syn match   mlirNumber /x\s*\zs-\?\d\+\ze\s*x/
 
 syn match   mlirFloat  /-\?\<\d\+\.\d*\(e[+-]\d\+\)\?\>/
 syn match   mlirFloat  /\<0x\x\+\>/
 syn keyword mlirBoolean true false
-syn match   mlirComment /\/\/.*$/
+" Spell checking is enabled only in comments by default.
+syn match   mlirComment /\/\/.*$/ contains=@Spell
 syn region  mlirString start=/"/ skip=/\\"/ end=/"/
 syn match   mlirLabel /[-a-zA-Z$._][-a-zA-Z$._0-9]*:/
-syn match   mlirIdentifier /[%@][a-zA-Z$._-][a-zA-Z0-9$._-]*/
-syn match   mlirIdentifier /[%@!]\d\+\>/
-syn match mlirMapSetOutline "#.*$"
+" Prefixed identifiers, including attribute aliases (starting with '#').
+syn match   mlirIdentifier /[%@#][a-zA-Z$._-][a-zA-Z0-9$._-]*/
+syn match   mlirIdentifier /[%@#!]\d\+\>/
 
 " Syntax-highlight lit test commands and bug numbers.
 syn match  mlirSpecialComment /\/\/\s*RUN:.*$/
 syn match  mlirSpecialComment /\/\/\s*CHECK:.*$/
 syn match  mlirSpecialComment "\v\/\/\s*CHECK-(NEXT|NOT|DAG|SAME|LABEL):.*$"
 syn match  mlirSpecialComment /\/\/\s*expected-error.*$/
 syn match  mlirSpecialComment /\/\/\s*expected-remark.*$/
 syn match  mlirSpecialComment /;\s*XFAIL:.*$/
 syn match  mlirSpecialComment /\/\/\s*PR\d*\s*$/
 syn match  mlirSpecialComment /\/\/\s*REQUIRES:.*$/
 
 if version >= 508 || !exists("did_c_syn_inits")
   if version < 508
     let did_c_syn_inits = 1
     command -nargs=+ HiLink hi link <args>
   else
     command -nargs=+ HiLink hi def link <args>
   endif
 
   HiLink mlirType Type
   HiLink mlirOps Statement
-  HiLink mlirMapSetOutline PreProc
   HiLink mlirNumber Number
   HiLink mlirComment Comment
   HiLink mlirString String
   HiLink mlirLabel Label
   HiLink mlirKeyword Keyword
   HiLink mlirBoolean Boolean
   HiLink mlirFloat Float
   HiLink mlirConstant Constant
   HiLink mlirSpecialComment SpecialComment
   HiLink mlirIdentifier Identifier
 
   delcommand HiLink
 endif
 
 let b:current_syntax = "mlir"