doc: improve description of subscripting of arrays

It wasn't clear the non-integers are cast to integers for subscripting,
rather than throwing an error.

Reported-by: [email protected]
Discussion: https://postgr.es/m/159538675800.624.7728794628229799531@wrigleys.postgresql.org

Backpatch-through: 9.5

diff --git a/doc/src/sgml/syntax.sgml b/doc/src/sgml/syntax.sgml
index c91554821f4bdd99ad4038273d457e8dbf3b5055..bdd6345d73fcdcaef83e7d6d7a9a10c1f4bf968b 100644 (file)
--- a/doc/src/sgml/syntax.sgml
+++ b/doc/src/sgml/syntax.sgml
@@ -1383,7 +1383,7 @@ CREATE FUNCTION dept(text) RETURNS dept
 
     (Here, the brackets [ ] are meant to appear literally.)
     Each subscript is itself an expression,
-    which must yield an integer value.
+    which will be rounded to the nearest integer value.