casting TEXT to CIDR (or to INET) has to be possible

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                        POSTGRESQL BUG REPORT TEMPLATE
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Your name        :    Paul Vixie
Your email address    :    paul@vix.com


System Configuration
---------------------
  Architecture (example: Intel Pentium)      :    Intel Dual Pentium

  Operating System (example: Linux 2.0.26 ELF)     :    Freebsd 4.3

  PostgreSQL version (example: PostgreSQL-7.1.1):   PostgreSQL-7.2devel

  Compiler used (example:  gcc 2.95.2)        :    gcc version 2.95.3


Please enter a FULL description of your problem:
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I know there's code in the server to convert presentation-format INET or CIDR
into internal format.  To get the effect of C's "inet_netof()" I need to be
able to do this conversion from TEXT rather than from interpreter literals.


Please describe a way to repeat the problem.   Please try to provide a
concise reproducible example, if at all possible:
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lartomatic=# select (host(relay)||'/18')::cidr from spam limit 5;
ERROR:  Cannot cast type 'text' to 'cidr'
lartomatic=# select (host(relay)||'/18')::inet from spam limit 5;
ERROR:  Cannot cast type 'text' to 'inet'



If you know how this problem might be fixed, list the solution below:
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Nope, this is beyond my abilities.