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Contents
module Bmg
module Sql
class Processor
class Merge < Processor
def initialize(kind, all, right, builder)
super(builder)
@kind = kind
@all = all
@right = right
end
def on_with_exp(sexpr)
if @right.with_exp?
reordered = Reorder.new(sexpr.to_attr_list, builder).call(@right)
main = [ @kind, modifier, sexpr.select_exp, reordered.select_exp ]
merge_with_exps(sexpr, reordered, main)
else
[ :with_exp,
sexpr.with_spec,
apply(sexpr.last) ]
end
end
def on_nonjoin_exp(sexpr)
left_attrs = sexpr.to_attr_list.map(&:to_s).sort
right_attrs = @right.to_attr_list.map(&:to_s).sort
unless left_attrs == right_attrs
raise "Operands are not union compatible: #{left_attrs.inspect} vs. #{right_attrs.inspect}"
end
reordered = Reorder.new(sexpr.to_attr_list, builder).call(@right)
if @right.with_exp?
[ :with_exp,
reordered.with_spec,
[ @kind, modifier, sexpr, reordered.select_exp ] ]
elsif sexpr.first == @kind && sexpr.set_quantifier == modifier
sexpr.dup + [ reordered ]
else
[ @kind, modifier, sexpr, reordered ]
end
end
alias :on_union :on_nonjoin_exp
alias :on_except :on_nonjoin_exp
alias :on_intersect :on_nonjoin_exp
alias :on_select_exp :on_nonjoin_exp
private
def modifier
@all ? builder.all : builder.distinct
end
end # class Merge
end # class Processor
end # module Sql
end # module Bmg
Version data entries
62 entries across 62 versions & 1 rubygems