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ecto lib ecto query builder group_by.ex
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lib/ecto/query/builder/group_by.ex

defmodule Ecto.Query.Builder.GroupBy do
@moduledoc false
alias Ecto.Query.Builder
@doc """
Escapes a list of quoted expressions.
See `Ecto.Builder.escape/2`.
iex> escape(quote do [x.x, foo()] end, [x: 0])
{[{:{}, [], [{:{}, [], [:., [], [{:{}, [], [:&, [], [0]]}, :x]]}, [], []]},
{:{}, [], [:foo, [], []]}],
%{}}
"""
@spec escape(Macro.t, Keyword.t) :: Macro.t
def escape(expr, vars) do
List.wrap(expr)
|> Builder.escape(vars)
end
@doc """
Builds a quoted expression.
The quoted expression should evaluate to a query at runtime.
If possible, it does all calculations at compile time to avoid
runtime work.
"""
@spec build(Macro.t, [Macro.t], Macro.t, Macro.Env.t) :: Macro.t
def build(query, binding, expr, env) do
binding = Builder.escape_binding(binding)
{expr, external} = escape(expr, binding)
external = Builder.escape_external(external)
group_by = quote do: %Ecto.Query.QueryExpr{
expr: unquote(expr),
external: unquote(external),
file: unquote(env.file),
line: unquote(env.line)}
Builder.apply_query(query, __MODULE__, [group_by], env)
end
@doc """
The callback applied by `build/4` to build the query.
"""
@spec apply(Ecto.Queryable.t, term) :: Ecto.Query.t
def apply(query, expr) do
query = Ecto.Queryable.to_query(query)
%{query | group_bys: query.group_bys ++ [expr]}
end
end