Electric.Replication.Eval.Expr (electric v1.4.11)

Parsed expression, available for evaluation using the runner

Summary

Functions

unqualified_refs(expr)

Returns a flat list of all used refs used in the expression that point to the current table

wrap_parser_part(expr)

Wrap a parser part (Const, Ref, Func, Array, RowExpr) in an Expr struct, so that it can be evaluated on it's own.

Types

t()

@type t() :: %Electric.Replication.Eval.Expr{
  eval: term(),
  query: String.t(),
  returns: Electric.Replication.Eval.Env.pg_type(),
  used_refs: used_refs()
}

used_refs()

@type used_refs() :: %{
  required([String.t(), ...]) => Electric.Replication.Eval.Env.pg_type()
}

Functions

unqualified_refs(expr)

@spec unqualified_refs(t()) :: [String.t()]

Returns a flat list of all used refs used in the expression that point to the current table

Examples

iex> used_refs = %{["id"] => :int8, ["created_at"] => :timestamp}
iex> unqualified_refs(%Expr{query: "id = 1", used_refs: used_refs})
["created_at", "id"]

iex> used_refs = %{["id"] => :int8, ["potato", "created_at"] => :timestamp}
iex> unqualified_refs(%Expr{query: "id = 1", used_refs: used_refs, returns: :int8})
["id"]

wrap_parser_part(expr)

Wrap a parser part (Const, Ref, Func, Array, RowExpr) in an Expr struct, so that it can be evaluated on it's own.

This is used when a subtree of our AST needs to be made evaluatable on it's own inside Electric. The query field is not needed in that context, it's used when going back to postgres, so we don't bother calculating it.