From d2cba4f2cbfe69b2c5f93f364da4e574e075cb03 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Mon, 22 Jul 2024 19:43:12 -0400 Subject: Doc: improve description of plpgsql's FETCH and MOVE commands. We were not being clear about which variants of the "direction" clause are permitted in MOVE. Also, the text seemed to be written with only the FETCH/MOVE NEXT case in mind, so it didn't apply very well to other variants. Also, document that "MOVE count IN cursor" only works if count is a constant. This is not the whole truth, because some other cases such as a parenthesized expression will also work, but we want to push people to use "MOVE FORWARD count" instead. The constant case is enough to cover what we allow in plain SQL, and that seems sufficient to claim support for. Update a comment in pl_gram.y claiming that we don't document that point. Per gripe from Philipp Salvisberg. Discussion: https://postgr.es/m/172155553388.702.7932496598218792085@wrigleys.postgresql.org --- src/pl/plpgsql/src/pl_gram.y | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'src') diff --git a/src/pl/plpgsql/src/pl_gram.y b/src/pl/plpgsql/src/pl_gram.y index a29d2dfacdd..97be9239e37 100644 --- a/src/pl/plpgsql/src/pl_gram.y +++ b/src/pl/plpgsql/src/pl_gram.y @@ -3219,11 +3219,11 @@ read_fetch_direction(void) { /* * Assume it's a count expression with no preceding keyword. - * Note: we allow this syntax because core SQL does, but we don't - * document it because of the ambiguity with the omitted-direction - * case. For instance, "MOVE n IN c" will fail if n is a variable. - * Perhaps this can be improved someday, but it's hardly worth a - * lot of work. + * Note: we allow this syntax because core SQL does, but it's + * ambiguous with the case of an omitted direction clause; for + * instance, "MOVE n IN c" will fail if n is a variable, because the + * preceding else-arm will trigger. Perhaps this can be improved + * someday, but it hardly seems worth a lot of work. */ plpgsql_push_back_token(tok); fetch->expr = read_sql_expression2(K_FROM, K_IN, -- cgit v1.2.3