Re: array support patch phase 1 patch

Joe Conway kirjutas E, 07.04.2003 kell 05:12:
> Joe Conway wrote:
> It covers the following:
> ----------------------------------------------------------------------
> 1. Support for polymorphic functions, accepting and returning ANYARRAY
>     and ANYELEMENT datatypes that are "tied" to each other and resolved
>     to an actual type at runtime. This also includes the ability to
>     define aggregates using the polymorphic functions.
>
> 2. Array handling functions:
>     - singleton_array(ANYELEMENT) returns ANYARRAY
>     - array_append(ANYARRAY, ANYELEMENT) returns ANYARRAY
>     - array_prepend(ANYELEMENT, ANYARRAY) returns ANYARRAY
>     - array_accum(ANYARRAY, ANYELEMENT) returns ANYARRAY
>     - array_assign(ANYARRAY, int, ANYELEMENT) returns ANYARRAY
>     - array_subscript(ANYARRAY, int) returns ANYELEMENT
>     - array_cat(ANYARRAY, ANYARRAY) returns ANYARRAY
>

How hard would it be to add

array_eq, array_ne, array_gt, array_le and corresponding operators

SELECT ARRAY[1,2,3] = ARRAY[1,2,3];  # --> TRUE
SELECT ARRAY[1,2,3] < ARRAY[1,2,3];  # --> FALSE
SELECT ARRAY[1,2,3] <= ARRAY[1,2,3];  # --> TRUE
SELECT ARRAY[1,2,3] > ARRAY[1,2,3];  # --> FALSE
SELECT ARRAY[1,2,3] >= ARRAY[1,2,3];  # --> TRUE

I'd assume them to behave like string comparisons, i.e shorter subarray
is smaller:

SELECT ARRAY[1,2] < ARRAY[1,2,3];  # --> FALSE

Support for sorting and b-tree indexing could be nice too.

> Still needs to be done (in roughly this order):
> ----------------------------------------------------------------------
> 1. Functions:
>     - str_to_array(str TEXT, delim TEXT) returns TEXT[]
>     - array_to_str(array ANYARRAY, delim TEXT) returns TEXT
>
> 2. Documentation update:
>      Update "User's Guide"->"Data Types"->"Arrays" documentation
>      create a new section: "User's Guide"->
>                            "Functions and Operators"->
>                            "Array Functions and Operators"
>
>
> 4. PL/pgSQL support for polymorphic types

Where should one start to add PL/Python support for polymorphic types ?

> 6. Move as much of contrib/intarray into backend as makes sense,
>     including migration to use polymorphic semantics (therefore make
>     work on other than int where possible). Note: this may not happen
>     for 7.4 as it looks to be fairly involved, at least at first glance.

What about moving contrib/intagg into backend ?

(And converting it into ANYagg on the way ;)

--------------------
Hannu