Обсуждение: Built-in casts for ltree

contrib/ltree includes text2ltree and ltree2text functions, but no
implicit casts. Is there any particular reason for this?

--- ltree.sql.in.orig   Mon Jan 24 22:47:01 2005
+++ ltree.sql.in        Mon Jan 24 22:58:40 2005
@@ -155,10 +155,14 @@AS 'MODULE_PATHNAME'LANGUAGE 'C' WITH (isstrict,iscachable);
+CREATE CAST (ltree AS text) WITH FUNCTION ltree2text(ltree) AS IMPLICIT;
+CREATE FUNCTION text2ltree(text)RETURNS ltreeAS 'MODULE_PATHNAME'LANGUAGE 'C' WITH (isstrict,iscachable);
+
+CREATE CAST (text AS ltree) WITH FUNCTION text2ltree(text) AS IMPLICIT;CREATE FUNCTION lca(_ltree)RETURNS ltree
-- 
Jim C. Nasby, Database Consultant               decibel@decibel.org 
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"Jim C. Nasby" <decibel@decibel.org> writes:
> contrib/ltree includes text2ltree and ltree2text functions, but no
> implicit casts. Is there any particular reason for this?

Implicit casts to or from text are evil.
        regards, tom lane