Thomas Lockhart <lockhart@fourpalms.org> writes:
> Are dollar signs currently allowed in operators?
Not at present. If they were, you'd have a problem telling whether
"$12" is a parameter identifier or a prefix "$" operator applied to an
integer constant.
However, this is no argument for allowing them into identifiers, since
doing so will equally create lexing ambiguity where there was none
before.
regards, tom lane