class Sequel::Postgres::PGRow::Parser
The Parser is responsible for taking the input string from PostgreSQL, and returning an appropriate ruby object that the type represents, such as an ArrayRow or HashRow.
Attributes
Converters for each member in the composite type. If not present, no conversion will be done, so values will remain strings. If present, should be an array of callable objects.
The OIDs for each member in the composite type. Not currently used, but made available for user code.
The columns for the parser, if any. If the parser has no columns, it will treat the input as an array. If it has columns, it will treat the input as a hash. If present, should be an array of strings.
The oid for the composite type itself.
A callable object used for typecasting the object. This is similar to the converter, but it is called by the typecasting code, which has different assumptions than the converter. For instance, the converter should be called with all of the member values already typecast, but the typecaster may not be.
Public Class Methods
Sets each of the parser's attributes, using options with the same name (e.g. :columns sets the columns attribute).
# File lib/sequel/extensions/pg_row.rb, line 296 def initialize(h=OPTS) @columns = h[:columns] @column_converters = h[:column_converters] @column_oids = h[:column_oids] @converter = h[:converter] @typecaster = h[:typecaster] @oid = h[:oid] end
Public Instance Methods
Convert the PostgreSQL composite type input format into an appropriate ruby object.
# File lib/sequel/extensions/pg_row.rb, line 307 def call(s) convert(convert_format(convert_columns(Splitter.new(s).parse))) end
Typecast the given object to the appropriate type using the typecaster. Note that this does not conversion for the members of the composite type, since those conversion expect strings and strings may not be provided.
# File lib/sequel/extensions/pg_row.rb, line 315 def typecast(obj) case obj when Array _typecast(convert_format(obj)) when Hash unless @columns raise Error, 'PGRow::Parser without columns cannot typecast from a hash' end _typecast(obj) else raise Error, 'PGRow::Parser can only typecast arrays and hashes' end end
Private Instance Methods
If the parser has a typecaster, call it with the object, otherwise return the object as is.
# File lib/sequel/extensions/pg_row.rb, line 333 def _typecast(obj) if t = @typecaster t.call(obj) else obj end end
If the parser has a converter, call it with the object, otherwise return the object as is.
# File lib/sequel/extensions/pg_row.rb, line 366 def convert(obj) if c = @converter c.call(obj) else obj end end
If the parser has column converters, map the array of strings input to a array of appropriate ruby objects, one for each converter.
# File lib/sequel/extensions/pg_row.rb, line 344 def convert_columns(arr) if ccs = @column_converters arr.zip(ccs).map{|v, pr| (v && pr) ? pr.call(v) : v} else arr end end
If the parser has columns, return a hash assuming that the array is ordered by the columns.
# File lib/sequel/extensions/pg_row.rb, line 354 def convert_format(arr) if cs = @columns h = {} arr.zip(cs).each{|v, c| h[c] = v} h else arr end end