264 lines
7.8 KiB
Ruby
264 lines
7.8 KiB
Ruby
# SmqlToAR - Builds AR-querys: Converts SMQL to ActiveRecord
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# Copyright (C) 2011 Denis Knauf
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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class SmqlToAR
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#######################################################################################
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# Baut die Queries zusammen.
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class QueryBuilder
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# Erzeugt einen eindeutigen Identikator "cX", wobei X iteriert wird.
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class Vid
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attr_reader :vid
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def initialize( vid) @vid = vid end
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def to_s() ":smql_c#{@vid}" end
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def to_sym() "smql_c#{@vid}".to_sym end
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alias sym to_sym
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def to_i() @vid end
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def === other
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to_s === other || to_sym === other || to_i === other || self == other || self === other
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end
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end
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class Aliases < Hash
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def self.new prefix, *a, &e
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e ||= lambda do |h, k|
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j = Array.wrap( k).compact
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h[k] = h.key?(j) ? h[j] : "#{prefix},#{j.collect( &:to_alias).join( ',')}"
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end
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super *a, &e
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end
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end
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attr_reader :table_alias, :model, :table_model, :base_table, :_where, :_select, :_wobs, :_joins, :prefix, :_vid
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attr_accessor :logger, :limit, :offset
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def initialize model, prefix = nil
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@prefix = "smql"
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@logger = SmqlToAR.logger
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@table_alias = Aliases.new @prefix
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@_vid, @_where, @_wobs, @model, @quoter = 0, SmqlToAR::And[], {}, model, model.connection
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@base_table = [Column::Col.new( model.table_name)]
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@table_alias[ @base_table] = @base_table.first
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t = quote_table_name @base_table.first.col
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@_select, @_joins, @_joined, @_includes, @_order = ["DISTINCT #{t}.*"], "", [@base_table], [], []
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@table_model = {@base_table => @model}
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end
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def vid() Vid.new( @_vid+=1) end
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def inspect
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"#<#{self.class.name}:#{"0x%x"% (self.object_id<<1)}|#{@prefix}:#{@base_table}:#{@model} vid=#{@_vid} where=#{@_where} wobs=#{@_wobs} select=#{@_select} aliases=#{@table_alias}>"
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end
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# Jede via where uebergebene Condition wird geodert und alle zusammen werden geundet.
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# "Konjunktive Normalform". Allerdings duerfen Conditions auch Komplexe Abfragen enthalten.
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# Ex: builder.where( ['a = a', 'b = c']).where( ['c = d', 'e = e']).where( 'x = y').where( ['( m = n AND o = p )', 'f = g'])
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# #=> WHERE ( a = a OR b = c ) AND ( c = d OR e = e ) AND x = y ( ( m = n AND o = p ) OR f = g )
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def where cond
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@_where.push cond
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self
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end
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def wobs vals
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@_wobs.update vals
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self
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end
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def quote_column_name name
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@quoter.quote_column_name( name).gsub /"\."/, ','
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end
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def quote_table_name name
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name = case name
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when Array, Column::Col then @table_alias[Array.wrap name]
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else name.to_s
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end
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@quoter.quote_table_name( name).gsub /"\."/, ','
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end
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def column table, name
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"#{quote_table_name table}.#{quote_column_name name}"
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end
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def build_join orig, pretable, table, prekey, key
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" LEFT JOIN #{orig} AS #{quote_table_name table} ON #{column pretable, prekey} = #{column table, key} "
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end
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def sub_joins table, col, model, query
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prefix, base_table = "#{@prefix}_sub", col.relation.table_name
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join_ table, model, "(#{query.build( prefix).ar.to_sql})"
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end
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def join_ table, model, query, pretable = nil
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pretable ||= table[0...-1]
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@table_model[ table] = model
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premodel = @table_model[ pretable]
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t = @table_alias[ table]
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pt = quote_table_name table[ 0...-1]
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refl = premodel.reflections[table.last.to_sym]
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case refl
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when ActiveRecord::Reflection::ThroughReflection
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through = refl.through_reflection
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throughtable = table[0...-1]+[Column::Col.new( through.name, table.last.as)]
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srctable = throughtable+[Column::Col.new( refl.source_reflection.name, table.last.as)]
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@table_model[ srctable] = model
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@table_alias[ table] = @table_alias[ srctable]
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join_ throughtable, through.klass, quote_table_name( through.table_name)
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join_ srctable, refl.klass, query, throughtable
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when ActiveRecord::Reflection::AssociationReflection
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case refl.macro
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when :has_many, :has_one
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@_joins += build_join query, pretable, t, premodel.primary_key, refl.primary_key_name
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when :belongs_to
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@_joins += build_join query, pretable, t, refl.primary_key_name, premodel.primary_key
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when :has_and_belongs_to_many
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jointable = [','] + table
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@_joins += build_join refl.options[:join_table], pretable, @table_alias[jointable], premodel.primary_key, refl.primary_key_name
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@_joins += build_join query, jointable, t, refl.association_foreign_key, refl.association_primary_key
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else raise BuilderError, "Unkown reflection macro: #{refl.macro.inspect}"
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end
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else raise BuilderError, "Unkown reflection type: #{refl.class.name}"
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end
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self
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end
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def joins table, model
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table = table.flatten.compact
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return self if @_joined.include? table # Already joined
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join_ table, model, quote_table_name( model.table_name)
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@_joined.push table
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end
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def includes table
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@_includes.push table
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self
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end
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def select col
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@_select.push quote_column_name( @table_alias[col])
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self
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end
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def order table, col, o
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ct = column table, col
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@_select.push ct
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@_order.push "#{ct} #{:DESC == o ? :DESC : :ASC}"
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self
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end
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def build_ar
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where_str = @_where.type_correction!.optimize!.build_where
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incls = {}
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@_includes.each do |inc|
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b = incls
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inc[1..-1].collect {|rel| b = b[rel] ||= {} }
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end
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@model = @model.
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select( @_select.join( ', ')).
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joins( @_joins).
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where( where_str, @_wobs).
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order( @_order.join( ', ')).
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includes( incls)
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@model = @model.limit @limit if @limit
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@model = @model.offset @offset if @offset
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@model
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end
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def fix_calculate
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def @model.calculate operation, column_name, options = nil
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options = options.try(:dup) || {}
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options[:distinct] = true unless options.except(:distinct).present?
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column_name = klass.primary_key unless column_name.present?
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super operation, column_name, options
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end
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self
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end
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def to_ar
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build_ar
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fix_calculate
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@model
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end
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end
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class SubBuilder < Array
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attr_reader :parent, :_where
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delegate :wobs, :joins, :includes, :sub_joins, :vid, :quote_column_name, :quoter, :quote_table_name, :column, :to => :parent
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def initialize parent, tmp = false
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@parent = parent
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@parent.where self unless @parend.nil? && tmp
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end
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def new parent, tmp = false
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super parent, tmp
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#return parent if self.class == parent.class
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#super parent
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end
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alias where push
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def type_correction!
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collect! do |sub|
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if sub.kind_of? Array
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sub = default[ *sub] unless sub.respond_to?( :type_correction!)
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sub.type_correction!
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end
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sub
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end
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self
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end
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def optimize!
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ext = []
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collect! do |sub|
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sub = sub.optimize! if sub.kind_of? Array
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if self.class == sub.class
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ext.push *sub
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nil
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elsif sub.blank?
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nil
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else
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sub
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end
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end.compact!
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push *ext
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self
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end
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def inspect
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"#{self.class.name.sub( /.*::/, '')}[ #{collect(&:inspect).join ', '}]"
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end
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def default() SmqlToAR::And end
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def default_new( parent) default.new self, parent, false end
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def collect_build_where
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collect {|x| x.respond_to?( :build_where) ? x.build_where : x.to_s }
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end
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end
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class And < SubBuilder
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def default; SmqlToAR::Or; end
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def build_where
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collect_build_where.join ' AND '
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end
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end
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class Or < SubBuilder
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def build_where
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collect_build_where.join ' OR '
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end
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end
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end
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