Experimentally highlight `type (...)` regions for Go

after/syntax/go.vim

@@ -1,19 +1,31 @@
+syn cluster goTypes contains=goType,goSignedInts,goUnsignedInts,goFloats,goComplexes
+syn cluster goNumber contains=goDecimalInt,goHexadecimalInt,goOctalInt,goFloat,goImaginary,goImaginaryFloat
+
 if !exists("g:go_highlight_fields")
   let g:go_highlight_fields = 0
 endif
 if g:go_highlight_fields != 0
-  syn match goField                 /\(\.\)\@<=\w\+\([.\ \n\r\)\[,]\)\@=/
-  " Match fields in type constructors
-  syn match goField                 /\([{, ]\|\s\)\@<=\w\+\(:\)\@=/
+  syn match goField                 /\(\.\)\@<=\w\+\([.\ \n\r\:\)\[,+-\*\\\]]\)\@=/
 endif
 
 if !exists("g:go_highlight_functions")
   let g:go_highlight_functions = 0
 endif
 if g:go_highlight_functions != 0
-  syn match goReceiver          /(\(\w\|[ *]\)\+)/ contained nextgroup=goFunction contains=goReceiverOpen,goReceiverVar,goReceiverClose skipwhite skipnl
-  syn match goReceiverOpen      /(/ contained
-  syn match goReceiverClose     /)/ contained
+  syn match goDeclaration          /\<func\>/ nextgroup=goReceiverRegion,goFunctionTagLine skipwhite skipnl
+  syn region goReceiverRegion      matchgroup=ContainerChars start=/(/ end=/)/ contains=goReceiver nextgroup=goFunction contained
+  syn match goReceiver             /\(\w\|[ *]\)\+/ contained contains=goReceiverVar skipwhite skipnl contained
+
+  syn clear goFunctionCall
+  syn clear goFunction
+
+  syn cluster validFuncRegionContains contains=@goTypes,goField,goDeclaration,GoBuiltins,goDeclStruct,goDeclInterface,OperatorChars,ContainerChars,goString,goRawString,@goNumber
+
+  syn match goFunctionTagLine       /\w\+(.\{-})\s*\((.\{-})\|\(\w\|\*\|\.\)\+\)\?/ nextgroup=goFunction contains=goFunction,goFunctionParamRegion,goFunctionReturnRegion,goFunctionReturn,OperatorChars,ContainerChars
+  syn region goFunctionParamRegion  matchgroup=ContainerChars start=/(/ end=/)/ contains=@validFuncRegionContains nextgroup=goFunctionReturnRegion,goFunctionReturn contained
+  syn region goFunctionReturnRegion matchgroup=ContainerChars start=/(/ end=/)/ contains=@validFuncRegionContains contained
+  syn match goFunctionReturn        /\w\+/ contains=@goTypes,goField,goDeclaration,GoBuiltins,goDeclStruct,goDeclInterface,OperatorChars,ContainerChars skipwhite contained
+  syn match goFunction              /\w\+\((\)\@=/  nextgroup=goFunctionParamRegion contained
 endif
 
 if !exists("g:go_highlight_types")
@@ -22,16 +34,59 @@ endif
 if g:go_highlight_types != 0
   syn match goTypeConstructor      /\<\w\+{/he=e-1 contains=goTypeOpen
   syn match goTypeOpen             /{/ contained
+  "syn match goTypeClose            /}/ contained
+
+  " TODO (maybe): handle only Type-highlighting things like xml.Name ignoring
+  " the first \w+\. and highlighting the remaining \w+
+  "
+  " This is most likely bad... probably very bad.. and brittle?
+  syn clear goTypeDecl
+  syn clear goTypeName
+  syn clear goDeclType
+
+  syn cluster validTypeContains          contains=goComment,goTypeField,goSTypeDefinition,goITypeDefinition,goString,goRawString,OperatorChars,ContainerChars
+  syn cluster validStructContains        contains=goComment,goTypeField,goSTypeDefinition,goITypeDefinition,goString,goRawString,@goTypes,goDeclStructRegion,OperatorChars,ContainerChars
+  syn cluster validInterfaceContains     contains=goComment,goFunctionTagLine,OperatorChars,ContainerChars
 
-  " Redefine so interface and struct isn't falsely matched as a type constructor
-  syn match goDeclType             /\<\(interface\|struct\)\>/ skipwhite skipnl
+  syn match goTypeDecl                   /\<type\>/ nextgroup=goSTypeDefinition,goITypeDefinition,goTypeRegion skipwhite skipnl
+  syn region goTypeRegion                matchgroup=ContainerChars start=/(/ end=/)/ contains=@validTypeContains fold contained
+  syn region goDeclStructRegion          matchgroup=ContainerChars start=/{/ end=/}/ contains=@validStructContains fold contained
+  syn region goDeclInterfaceRegion       matchgroup=ContainerChars start=/{/ end=/}/ contains=@validInterfaceContains fold contained
+
+  syn match goTypeField                  /\w\+\s\+\(\*\|\[.\{-}\]\)*\(\w\|\.\)\+/ contains=goDeclTypeField,goDeclTypeFieldPointerOp,goDeclTypeFieldSlice,goDeclTypeFieldType skipwhite contained
+  syn match goDeclTypeFieldPointerOp     /\*/ nextgroup=goDeclTypeFieldPointerOp,goDeclTypeFieldSlice,goDeclTypeFieldType skipwhite contained
+  syn region goDeclTypeFieldSlice        matchgroup=ContainerChars start=/\[/ end=/\]/ contains=goDecimalInt,goHexadecimalInt,goOctalInt nextgroup=goDeclTypeFieldPointerOp,goDeclTypeFieldSlice,goDeclTypeFieldType skipwhite contained
+  syn match goDeclTypeFieldType          /\(\w\+\s\+\(\*\|\[.\{-}\]\)*\)\@<=\(\w\|\.\)\+/ skipwhite contained
+  syn match goDeclTypeField              /\w\+/ nextgroup=goDeclTypeFieldPointerOp,goDeclTypeFieldSlice,goDeclTypeFieldType skipwhite contained
+
+  syn match goSTypeDefinition            /\w\+\s\+\(\*\|\[.\{-}\]\)*\<struct\>/ nextgroup=goDeclStructRegion contains=goSTypeName,goSTypeDefPointerOp,goSTypeDefSlice,goDeclStruct skipwhite skipnl contained
+  syn match goSTypeName                  /\w\+/ nextgroup=goSTypeDefPointerOp,goSTypeDefSlice,goDeclStruct skipwhite contained
+  syn match goSTypeDefPointerOp          /\*/ nextgroup=goSTypeDefPointerOp,goSTypeDefSlice,goDeclStruct skipwhite contained
+  syn region goSTypeDefSlice             matchgroup=ContainerChars start=/\[/ end=/\]/ contains=goDecimalInt,goHexadecimalInt,goOctalInt nextgroup=goSTypeDefPointerOp,goSTypeDefSlice,goDeclStruct skipwhite contained
+  syn match goDeclStruct                 /\<struct\>/ nextgroup=goDeclStructRegion skipwhite skipnl
+
+  syn match goITypeDefinition            /\w\+\s\+\(\*\|\[.\{-}\]\)*\<interface\>/ nextgroup=goDeclInterfaceRegion contains=goITypeName,goITypeDefPointerOp,goITypeDefSlice,goDeclInterface skipwhite skipnl contained
+  syn match goITypeName                  /\w\+/ nextgroup=goITypeDefPointerOp,goITypeDefSlice,goDeclInterface skipwhite contained
+  syn match goITypeDefPointerOp          /\*/ nextgroup=goITypeDefPointerOp,goITypeDefSlice,goDeclInterface skipwhite contained
+  syn region goITypeDefSlice             matchgroup=ContainerChars start=/\[/ end=/\]/ contains=goDecimalInt,goHexadecimalInt,goOctalInt nextgroup=goITypeDefPointerOp,goITypeDefSlice,goDeclInterface skipwhite contained
+  syn match goDeclInterface              /\<interface\>/ nextgroup=goDeclInterfaceRegion skipwhite skipnl
 endif
 
-hi link goReceiverOpen    ContainerChars
-hi link goReceiverClose   ContainerChars
-hi link goTypeOpen        ContainerChars
+hi link goPointerOperator        Operator
+hi link goITypeDefPointerOp      Operator
+hi link goSTypeDefPointerOp      Operator
+hi link goDeclTypeFieldPointerOp Operator
+
+hi link goTypeConstructor        Type
+hi link goTypeOpen               ContainerChars
+
+hi link goSTypeName              Type
+hi link goITypeName              Type
+hi link goDeclTypeFieldType      Type
 
-hi link goPointerOperator Operator
+hi link goDeclInterface          Keyword
+hi link goDeclStruct             Keyword
 
-hi link goMethodCall   Function
-hi link goFunctionCall Function
+hi link goFunction               Function
+hi link goMethodCall             Function
+hi link goFunctionCall           Function