# module PG::BasicTypeRegistry

This module defines the mapping between OID and encoder/decoder classes for `PG::BasicTypeMapForResults`, `PG::BasicTypeMapForQueries` and `PG::BasicTypeMapBasedOnResult`.

Additional types can be added like so:

    require 'pg'
    require 'ipaddr'

    class InetDecoder < PG::SimpleDecoder
      def decode(string, tuple=nil, field=nil)
        IPAddr.new(string)
      end
    end
    class InetEncoder < PG::SimpleEncoder
      def encode(ip_addr)
        ip_addr.to_s
      end
    end

    # 0 if for text format, can also be 1 for binary
    PG::BasicTypeRegistry.register_type(0, 'inet', InetEncoder, InetDecoder)

### Constants

CODERS_BY_NAME

  The key of this hash maps to the `typname` column from the table. encoder_map is then dynamically built with oids as the key and Type objects as values.

ValidDirections
ValidFormats

### Public Class Methods

alias_type(format, new, old) click to toggle source

Alias the `old` type to the `new` type.

    # File lib/pg/basic_type_mapping.rb, line 180
    def self.alias_type(format, new, old)
            [:encoder, :decoder].each do |ende|
                    enc = CODERS_BY_NAME[format][ende][old]
                    if enc
                            CODERS_BY_NAME[format][ende][new] = enc
                    else
                            CODERS_BY_NAME[format][ende].delete(new)
                    end
            end
    end

register_coder(coder) click to toggle source

Register an encoder or decoder instance for casting a PostgreSQL type.

`Coder#name` must correspond to the `typname` column in the `pg_type` table. `Coder#format` can be 0 for text format and 1 for binary.

    # File lib/pg/basic_type_mapping.rb, line 163
    def self.register_coder(coder)
            h = CODERS_BY_NAME[coder.format] ||= { encoder: {}, decoder: {} }
            name = coder.name || raise(ArgumentError, "name of #{coder.inspect} must be defined")
            h[:encoder][name] = coder if coder.respond_to?(:encode)
            h[:decoder][name] = coder if coder.respond_to?(:decode)
    end

register_type(format, name, encoder_class, decoder_class) click to toggle source

Register the given `encoder_class` and/or `decoder_class` for casting a PostgreSQL type.

`name` must correspond to the `typname` column in the `pg_type` table. `format` can be 0 for text format and 1 for binary.

    # File lib/pg/basic_type_mapping.rb, line 174
    def self.register_type(format, name, encoder_class, decoder_class)
            register_coder(encoder_class.new(name: name, format: format)) if encoder_class
            register_coder(decoder_class.new(name: name, format: format)) if decoder_class
    end

### Protected Instance Methods

check_format_and_direction(format, direction) click to toggle source

    # File lib/pg/basic_type_mapping.rb, line 146
    def check_format_and_direction(format, direction)
            raise(ArgumentError, "Invalid format value %p" % format) unless ValidFormats[format]
            raise(ArgumentError, "Invalid direction %p" % direction) unless ValidDirections[direction]
    end