encodings/missing_converters.rb

tests/_examples/encodings/missing_converters.rb in the metorex repository.

# Some encodings have no converter to or from anything else. Text that is all
# ASCII reads the same in any ASCII-compatible one, so it is relabeled without
# a converter, and anything else is refused.
p "\x79".b.encode(Encoding::Emacs_Mule).encoding
p "abc".encode("EUC-TW").encoding

def refusal
  yield
rescue Encoding::ConverterNotFoundError => problem
  problem.message
end

p refusal { "\x80".b.encode Encoding::Emacs_Mule }
p refusal { "café".encode "EUC-TW" }
p refusal { Encoding::Converter.new Encoding::Emacs_Mule, Encoding::BINARY }

# A dummy encoding has no converter even for ASCII text, and a name that is no
# encoding at all is refused the same way.
p refusal { "abc".encode "UTF-7" }
p refusal { "abc".encode "xyz" }

# With no encoding named, `encode` writes the string in the default internal
# encoding, or answers a copy when there is none.
held = [0xA4, 0xA2].pack("C*").force_encoding Encoding::EUC_JP
p held.encode.encoding
p held.encode.equal? held
Encoding.default_internal = Encoding::UTF_8
p held.encode
p held.encode.encoding
Encoding.default_internal = Encoding::Emacs_Mule
p "\x79".b.encode.encoding
p refusal { "\x80".b.encode }
Encoding.default_internal = nil

Output:

#<Encoding:Emacs-Mule>
#<Encoding:EUC-TW>
"code converter not found (ASCII-8BIT to Emacs-Mule)"
"code converter not found (UTF-8 to EUC-TW)"
"code converter not found (Emacs-Mule to ASCII-8BIT)"
"code converter not found (UTF-8 to UTF-7)"
"code converter not found (UTF-8 to xyz)"
#<Encoding:EUC-JP>
false
"あ"
#<Encoding:UTF-8>
#<Encoding:Emacs-Mule>
"code converter not found (ASCII-8BIT to Emacs-Mule)"