undefined method 'separator_chars' error when using default_msh: false

[speckins]

msg = SimpleHL7::Message.new default_msh: false
msg.msh[1] = '|'
msg.msh[2] = '^~\&'
puts msg.to_hl7

Results in:

~/.gem/ruby/2.7.1/gems/simple_hl7-1.0.2/lib/simple_hl7/message.rb:33:in `to_hl7': undefined method `separator_chars' for #<SimpleHL7::Segment:0x00007fe530845a90> (NoMethodError)

This is because #to_hl7 assumes that the MSH segment is the Segment subclass MSHSegment, which responds to #separator_chars.

I could solve this by explicitly instantiating an MSHSegment and using #append_segment, but it might be nicer if the Message class either defined an explicit #msh method or added an "MSH" clause to #method_missing that instantiated the subclass.

[hportlock]

Thanks for the thorough bug report! I think it would make sense for get_named_segment to be a bit smarter with the MSH. I'll work on a fix for it.