On 14.03.2016 17:54, Tom Lane wrote:
Joe Conway <m...@joeconway.com> writes:
This new version of the patch was posted after the commitfest item was
marked ready for committer. Does anyone have further comments or
objections to the concept or syntax before I try to take this forward?


The quoted excerpt fails to say what solution was adopted to the array
syntax issues, so it's impossible to have an opinion without actually
reading the patch.

However ... one thing I was intending to mention on this thread is that
"get the array type over this type" isn't the only extension one might
wish for.  Another likely desire is "get the type of field 'foo' of this
composite type".  I don't suggest that this patch needs to implement
that right now; but it would be a good thing if we could see how the
chosen syntax could be extended in such a direction.  Otherwise we might
be painting ourselves into a corner.

                        regards, tom lane


I looked this patch and the previous. The patch applies correctly to HEAD. Regression tests pass successfully, without errors.

In comparison with the previous patch it adds the following functionality:
- %TYPE - now can be used for composite types (same syntax).
- %TYPE[] - new functionality, provides the array type from a
variable or table column (syntax was changed).
- var ELEMENT OF othervar%TYPE - new funcitonality, provides the element type of a given array (syntax was changed).

Was changed plpgsql_derive_type(). Now it has the following definition:

PLpgSQL_type *
plpgsql_derive_type(PLpgSQL_type *base_type, bool to_element_type, bool 
to_array_type)

Previously it had the following definition:

static PLpgSQL_type *
derive_type(PLpgSQL_type *base_type, PLpgSQL_reftype reftype)

where PLpgSQL_reftype was the enum:

+ typedef enum
+ {
+       PLPGSQL_REFTYPE_TYPE,           /* use type of some variable */
+       PLPGSQL_REFTYPE_ELEMENT,        /* use a element type of referenced 
variable */
+       PLPGSQL_REFTYPE_ARRAY           /* use a array type of referenced 
variable */
+ } PLpgSQL_reftype;

I think the previous version was better, because enum is better than additional function parameters. But it is only for me.

Also there is a little typo here:

+  * This routine is used for generating element or array type from base type.
+  * The options to_element_type and to_array_type can be used together, when
+  * we would to ensure valid result. The array array type is original type, so
+  * this direction is safe. The element of scalar type is not allowed, but if
+  * we do "to array" transformation first, then this direction should be safe
+  * too. This design is tolerant, because we should to support a design of
+  * polymorphic parameters, where a array value can be passed as anyelement
+  * or anyarray parameter.
+  */
+ PLpgSQL_type *
+ plpgsql_derive_type(PLpgSQL_type *base_type,

Here the word "array" occurs two times in the third line.

--
Artur Zakirov
Postgres Professional: http://www.postgrespro.com
Russian Postgres Company


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