tsearch2: how to plainto_tsquery() with "|"

i can run "...@@ to_tsquery('cat | dog')".

but if i run "...@@ to_tsquery('cat dog')", it gives me a syntax error (#42601).

so i run "...@@ plainto_tsquery('cat dog')".

but then i can't run "...@@ plainto_tsquery('cat | dog')".

can you help before i give up on tsearch2?

thks, jzs

http://postgresql.1045698.n5.nabble.com/tsearch2-plainto-tsquery-with-OR-td1885955.html
http://www.postgresql.org/docs/9.3/static/textsearch.html