---input---
def ::(xs: List[T]): List[T] = ::(x, xs)

---tokens---
'def'         Keyword
' '           Text.Whitespace
'::'          Name.Function
'('           Punctuation
'xs'          Name
':'           Punctuation
' '           Text.Whitespace
'List'        Name.Class
'['           Punctuation
'T'           Name.Class
']'           Punctuation
')'           Punctuation
':'           Punctuation
' '           Text.Whitespace
'List'        Name.Class
'['           Punctuation
'T'           Name.Class
']'           Punctuation
' '           Text.Whitespace
'='           Operator
' '           Text.Whitespace
'::'          Name
'('           Punctuation
'x'           Name
','           Punctuation
' '           Text.Whitespace
'xs'          Name
')'           Punctuation
'\n'          Text.Whitespace