-
::and:::are only permitted within certain contexts; the parser is currently permissive about where these tokens are found. -
Equality operators (
<,<=,>,>=,=,!=) can only occur once within the same level of an expression. -
->and->>need to be translated into<-and<<-when generating the R parse tree.
Remove it? It really just tries to check for parse errors but the parser itself is equipped to do that.