Tired of the duplication in writing code like %{id: id, first_name: first_name, last_name: last_name}? Dry it up with ~M{id, first_name, last_name}.

Here are the syntactic variants the macro exposes:

• Atom keys: ~M{a, b} => %{a: a, b: b}
• String keys: ~m{a, b} => %{“a” => a, “b” => b}
• Structs: ~M{%Person id, name} => %Person{id: id, name: name}
• Pinned variables: ~M{^a, b} => %{a: ^a, b: b}
• Ignore matching: ~M{_a, b} => %{a: _a, b: b}
• Map update: ~M{old|a, b, c} => %{old|a: a, b: b, c: c}
• Mixed mode: ~M{a, b: b_alt} => %{a: a, b: b_alt}

~M and ~m (atom vs. string keys) can be used to replace maps anywhere in your code: creating maps from existing variables, creating new variables while destructuring maps, pattern matching in lambdas, function heads or case statements.

See it on Github. Get it with {:shorter_maps, “~> 2.0”},