polytonic Greek: diacritics above long vowels ᾱ, ῑ, ῡ

Hi,

If one wants to indicate vowel length for the length-ambiguous vowels α,
ι, υ in Ancient Greek, one writes ᾱ, ῑ, ῡ. Is there a reason for why
there are no diacritic-precomposed characters? I guess it's because
macron usage is rare in orthographic practice, even though vowel length
here is not clearly less important than the other phonetic aspects
indicated by the various diacritics in use in polytonic orthography.
Thus I am wondering when and how the relevant decisions were made.

ἀγορᾱ́ ("gathering, marketplace") needs a combining diacritic at the end.
ῑ̓́φιος ("fat, strong") has ῑ̓́ (which should be thought of as ῑ with two
combining diacritics: U+1FD1 U+0313 U+0301). Multiple combining
diacritics work for me, but I'd like to check whether there are further
thoughts on this topic.

Stephan
Received on Fri Aug 02 2013 - 21:35:08 CDT