mtry macro for crystal

mtry.cr

# sample of a macro that flood the method calls with `#try`
# as a POC it does not support methods with arguments
macro mtry(expr)
  {% if expr.is_a?(Call) %}
    mtry({{expr.receiver}}).try(&.{{expr.name}})
  {% else %}
    {{expr}}
  {% end %}
end

class Foo
  @x = 0

  getter x

  def m
    @x += 1
    rand > 0.3 ? self : nil
  end
end

f = Foo.new
f.try(&.m.try(&.m.try(&.m.try(&.m.try(&.m.try(&.m))))))
puts f.x

g = Foo.new
mtry g.m.m.m.m.m.m
puts g.x