New in version 2.0.
List ordered named chromatic pitch pairs from expr_1 to expr_2:
abjad> chord_1 = Chord([0, 1, 2], (1, 4))
abjad> chord_2 = Chord([3, 4], (1, 4))
abjad> for pair in pitchtools.list_ordered_named_chromatic_pitch_pairs_from_expr_1_to_expr_2(chord_1, chord_2):
... pair
(NamedChromaticPitch("c'"), NamedChromaticPitch("ef'"))
(NamedChromaticPitch("c'"), NamedChromaticPitch("e'"))
(NamedChromaticPitch("cs'"), NamedChromaticPitch("ef'"))
(NamedChromaticPitch("cs'"), NamedChromaticPitch("e'"))
(NamedChromaticPitch("d'"), NamedChromaticPitch("ef'"))
(NamedChromaticPitch("d'"), NamedChromaticPitch("e'"))
Return generator.