Re: Re: UNION JOIN vs UNION SELECT
Tom Lane <tgl@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
To: chris@bitmead.com
Cc: pgsql-hackers@postgreSQL.org
Date: 2000-08-29T00:27:27Z
Lists: pgsql-hackers
Chris <chrisb@nimrod.itg.telstra.com.au> writes: >> the grammar is just plain not LR(1) unless you >> count UNION JOIN as a single token. > Would it be bad to make UNION JOIN as a single token? That's exactly the solution I'm proposing. However, it's pretty painful to make the lexer do it directly (consider intervening comments, for example) so what I have in mind is a filter between the parser and lexer that does one-token lookahead when it finds a UNION token. If next token is JOIN, pass back just one UNIONJOIN token, else stash away the second token to be returned on next call from parser. regards, tom lane