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module Bmg
module Sql
class Processor
class Clip < Processor
def initialize(attributes, allbut = false, on_empty = :is_table_dee, builder)
super(builder)
@attributes = attributes
@allbut = allbut
@on_empty = on_empty
end
attr_reader :attributes, :on_empty
def allbut?
@allbut
end
def on_set_operator(sexpr)
apply(builder.from_self(sexpr))
end
alias :on_union :on_set_operator
alias :on_except :on_set_operator
alias :on_intersect :on_set_operator
def on_select_exp(sexpr)
catch(:empty){ return super(sexpr) }
send("select_#{on_empty}", sexpr)
end
def on_select_star(sexpr)
raise NotImplementedError, "Allbut on * is not supported" if allbut?
builder.select_list(attributes, builder.last_qualifier)
end
def on_select_list(sexpr)
allbut = self.allbut?
result = sexpr.select{|child|
(child == :select_list) or
attributes.include?(child.as_name.to_sym) == !allbut
}
(result.size==1) ? throw(:empty) : result
end
private
def select_is_table_dee(sexpr)
builder.select_is_table_dee(select_star(sexpr))
end
def select_star(sexpr)
All.new(builder).call(Star.new(builder).call(sexpr))
end
end # class Clip
end # class Processor
end # module Sql
end # module Bmg
Version data entries
66 entries across 66 versions & 1 rubygems