A simple list of the right Unicode chars for writing Ancient Greek, with some additional info like Beta Code correspondences.
In this table, I present the Unicode character for all potential combinations (in theory) of Greek alphabet letters with the diacritics used in transcribing ancient literary Greek: spiritus lenis or asper, accent (acute, grave, or circumflex), diaeresis, and iota subscript or adscript, in addition to the symbols for short and long with the simple vowel. The table's purpose is to assist those seeking any combination of these signs and to promote the use of the most appropriate characters for writing ancient Greek, which are found in the "Basic Multilingual Plane> Block: Greek Extended" (U+1F00-U+1FFF).
In common usage, it is still quite frequent to find texts that mix characters from this section of the block corresponding to ancient Greek with characters from the modern Greek block or from any other source. While in most cases this does not pose major problems for basic text reading, it can become a significant inconvenience when attempting to edit texts from various origins or when trying to make them interoperable.
I also provide the correspondence with the Beta Code format (used, for example, in the Thesaurus linguae Graecae until version #E, cf. https://stephanus.tlg.uci.edu/encoding/BCM.pdf) and the complex sign obtained by adding each diacritic to the simple character (a resource used in some Natural Language Processing tools) in the hope that the table will also be useful to linguists and programmers.
In the table, the following information is provided:
Column 1: The ancient Greek character in the most recommended Unicode encoding.
Column 2: A unique numerical value assigned to each character in the Unicode standard.
Column 3: the same value in hexadecimal notation.
Column 4: The character, composed of as many signs and diacritics as it contains.
Column 5: The codepoints corresponding to each of the characters forming this composite sign
Column 6: the same codepoints as in the previous column, in hexadecimal notation
Column 7: The representation of this character in Beta Code
Column 8: Description of the character using the English name of the letter and the following
terms to describe the diacritics (as in modern Greek): "uppercase, lowercase" for capital
or small letter; "psili and dasia" for spiritus lenis or asper; "oxia, varia, or perispomeni"
for the acute, grave, or circumflex accents; "hypogegrammeni" for the subscript (iota);
"dialytika" for the diaeresis mark, "long_sign, "+short_sign" for the symbol indicating
the vowel as short or long.
Daniel Riaño Rufilanchas