How to insert Greek with "ascii keyboard" and XeTeX, Polyglossia

I get satisfying results by converting this asciitogreek.map file

; TECkit mapping for ASCII Greek <-> Unicode characters

LHSName "TeX-text"
RHSName "UNICODE"

pass(Unicode)

; Class "letter" consists of letters and characters denoting accents
; in order to cope with "sigma finalis", i.e., A-Z a-z ` ' > < ~
; we don't need the double quote because it goes only after a vowel
UniClass[letter] = ( U+0041..U+005A U+0061..U+007A U+0060 U+0027 U+003E U+003C U+007E )


; ligatures from Knuth's original CMR fonts
U+002D U+002D <> U+2013 ; -- -> en dash
U+002D U+002D U+002D <> U+2014 ; --- -> em dash

; Greek (according to C. Beccari conventions)

; (-1)
U+0022 <> U+2019 ; APOSTROPHE
U+0060 U+0060 <> U+201C ; `` -> LEFT DOUBLE QUOTATION MARK
U+0027 U+0027 <> U+201D ; '' -> RIGHT DOUBLE QUOTATION MARK
U+003C U+003C <> U+00AB ; << -> LEFT-POINTING DOUBLE ANGLE QUOTATION MARK
U+003E U+003E <> U+00BB ; >> -> RIGHT-POINTING DOUBLE ANGLE QUOTATION MARK
U+0028 U+0028 <> U+00AB ; (( -> LEFT-POINTING DOUBLE ANGLE QUOTATION MARK
U+0029 U+0029 <> U+00BB ; )) -> RIGHT-POINTING DOUBLE ANGLE QUOTATION MARK

; (0) basic letters
; uppercase
U+0041 <> U+0391 
U+0042 <> U+0392 
U+0044 <> U+0394 
U+0045 <> U+0395 
U+0046 <> U+03A6 
U+0047 <> U+0393 
U+0048 <> U+0397 
U+0049 <> U+0399 
U+004A <> U+0398 
U+004B <> U+039A 
U+004C <> U+039B 
U+004D <> U+039C 
U+004E <> U+039D 
U+004F <> U+039F 
U+0050 <> U+03A0 
U+0051 <> U+03A7 
U+0052 <> U+03A1 
U+0053 <> U+03A3 
U+0054 <> U+03A4 
U+0055 <> U+03A5 
U+0057 <> U+03A9 
U+0058 <> U+039E 
U+0059 <> U+03A8 
U+005A <> U+0396 
; lowercase
U+0061 <> U+03B1 
U+0062 <> U+03B2 
U+0063 <> U+03C2 
U+0064 <> U+03B4 
U+0065 <> U+03B5 
U+0066 <> U+03C6 
U+0067 <> U+03B3 
U+0068 <> U+03B7 
U+0069 <> U+03B9 
U+006A <> U+03B8 
U+006B <> U+03BA 
U+006C <> U+03BB 
U+006D <> U+03BC 
U+006E <> U+03BD 
U+006F <> U+03BF 
U+0070 <> U+03C0 
U+0071 <> U+03C7 
U+0072 <> U+03C1 
U+0073 <> U+03C3 
U+0073 / _ ^[letter] <> U+03C2 
U+0074 <> U+03C4 
U+0075 <> U+03C5 
U+0077 <> U+03C9 
U+0078 <> U+03BE 
U+0079 <> U+03C8 
U+007A <> U+03B6 

; (1) ` + letter -> varia
U+0060 U+0041 <> U+1FBA 
U+0060 U+0061 <> U+1F70 
U+0060 U+0045 <> U+1FC8 
U+0060 U+0065 <> U+1F72 
U+0060 U+0048 <> U+1FCA 
U+0060 U+0068 <> U+1F74 
U+0060 U+0049 <> U+1FDA 
U+0060 U+0069 <> U+1F76 
U+0060 U+004F <> U+1FF8 
U+0060 U+006F <> U+1F78 
U+0060 U+0055 <> U+1FEA 
U+0060 U+0075 <> U+1F7A 
U+0060 U+0057 <> U+1FFA 
U+0060 U+0077 <> U+1F7C 

; (2) ' + letter -> oxia
U+0027 U+0041 <> U+1FBB 
U+0027 U+0061 <> U+1F71 
U+0027 U+0045 <> U+1FC9 
U+0027 U+0065 <> U+1F73 
U+0027 U+0048 <> U+1FCB 
U+0027 U+0068 <> U+1F75 
U+0027 U+0049 <> U+1FDB 
U+0027 U+0069 <> U+1F77 
U+0027 U+004F <> U+1FF9 
U+0027 U+006F <> U+1F79 
U+0027 U+0055 <> U+1FEB 
U+0027 U+0075 <> U+1F7B 
U+0027 U+0057 <> U+1FFB 
U+0027 U+0077 <> U+1F7D 

; (3) > + letter -> psili
U+003E U+0041 <> U+1F08 
U+003E U+0061 <> U+1F00 
U+003E U+0045 <> U+1F18 
U+003E U+0065 <> U+1F10 
U+003E U+0048 <> U+1F28 
U+003E U+0068 <> U+1F20 
U+003E U+0049 <> U+1F38 
U+003E U+0069 <> U+1F30 
U+003E U+004F <> U+1F48 
U+003E U+006F <> U+1F40 
U+003E U+0055 <> U+1FBF U+03A5 
U+003E U+0075 <> U+1F50 
U+003E U+0057 <> U+1F68 
U+003E U+0077 <> U+1F60 

; (4) < + letter -> dasia
U+003C U+0041 <> U+1F09 
U+003C U+0061 <> U+1F01 
U+003C U+0045 <> U+1F19 
U+003C U+0065 <> U+1F11 
U+003C U+0048 <> U+1F29 
U+003C U+0068 <> U+1F21 
U+003C U+0049 <> U+1F39 
U+003C U+0069 <> U+1F31 
U+003C U+004F <> U+1F49 
U+003C U+006F <> U+1F41 
U+003C U+0055 <> U+1F59 
U+003C U+0075 <> U+1F51 
U+003C U+0057 <> U+1F69 
U+003C U+0077 <> U+1F61 

; (5) >` + letter -> psili and varia
U+003E U+0060 U+0041 <> U+1F0A 
U+003E U+0060 U+0061 <> U+1F02 
U+003E U+0060 U+0045 <> U+1F1A 
U+003E U+0060 U+0065 <> U+1F12 
U+003E U+0060 U+0048 <> U+1F2A 
U+003E U+0060 U+0068 <> U+1F22 
U+003E U+0060 U+0049 <> U+1F3A 
U+003E U+0060 U+0069 <> U+1F32 
U+003E U+0060 U+004F <> U+1F4A 
U+003E U+0060 U+006F <> U+1F42 
U+003E U+0060 U+0055 <> U+1FCD U+03A5 
U+003E U+0060 U+0075 <> U+1F52 
U+003E U+0060 U+0057 <> U+1F6A 
U+003E U+0060 U+0077 <> U+1F62 

; (6) `> + letter -> psili and varia
U+0060 U+003E U+0041 <> U+1F0A 
U+0060 U+003E U+0061 <> U+1F02 
U+0060 U+003E U+0045 <> U+1F1A 
U+0060 U+003E U+0065 <> U+1F12 
U+0060 U+003E U+0048 <> U+1F2A 
U+0060 U+003E U+0068 <> U+1F22 
U+0060 U+003E U+0049 <> U+1F3A 
U+0060 U+003E U+0069 <> U+1F32 
U+0060 U+003E U+004F <> U+1F4A 
U+0060 U+003E U+006F <> U+1F42 
U+0060 U+003E U+0055 <> U+1FCD U+03A5 
U+0060 U+003E U+0075 <> U+1F52 
U+0060 U+003E U+0057 <> U+1F6A 
U+0060 U+003E U+0077 <> U+1F62 

; (7) >' + letter -> psili and oxia
U+003E U+0027 U+0041 <> U+1F0C 
U+003E U+0027 U+0061 <> U+1F04 
U+003E U+0027 U+0045 <> U+1F1C 
U+003E U+0027 U+0065 <> U+1F14 
U+003E U+0027 U+0048 <> U+1F2C 
U+003E U+0027 U+0068 <> U+1F24 
U+003E U+0027 U+0049 <> U+1F3C 
U+003E U+0027 U+0069 <> U+1F34 
U+003E U+0027 U+004F <> U+1F4C 
U+003E U+0027 U+006F <> U+1F44 
U+003E U+0027 U+0055 <> U+1FCE U+03A5 
U+003E U+0027 U+0075 <> U+1F54 
U+003E U+0027 U+0057 <> U+1F6C 
U+003E U+0027 U+0077 <> U+1F64 

; (8) '> + letter -> psili and oxia
U+0027 U+003E U+0041 <> U+1F0C 
U+0027 U+003E U+0061 <> U+1F04 
U+0027 U+003E U+0045 <> U+1F1C 
U+0027 U+003E U+0065 <> U+1F14 
U+0027 U+003E U+0048 <> U+1F2C 
U+0027 U+003E U+0068 <> U+1F24 
U+0027 U+003E U+0049 <> U+1F3C 
U+0027 U+003E U+0069 <> U+1F34 
U+0027 U+003E U+004F <> U+1F4C 
U+0027 U+003E U+006F <> U+1F44 
U+0027 U+003E U+0055 <> U+1FCE U+03A5 
U+0027 U+003E U+0075 <> U+1F54 
U+0027 U+003E U+0057 <> U+1F6C 
U+0027 U+003E U+0077 <> U+1F64 

; (9) <` + letter -> dasia and varia
U+003C U+0060 U+0041 <> U+1F0B 
U+003C U+0060 U+0061 <> U+1F03 
U+003C U+0060 U+0045 <> U+1F1B 
U+003C U+0060 U+0065 <> U+1F13 
U+003C U+0060 U+0048 <> U+1F2B 
U+003C U+0060 U+0068 <> U+1F23 
U+003C U+0060 U+0049 <> U+1F3B 
U+003C U+0060 U+0069 <> U+1F33 
U+003C U+0060 U+004F <> U+1F4B 
U+003C U+0060 U+006F <> U+1F43 
U+003C U+0060 U+0055 <> U+1F5B 
U+003C U+0060 U+0075 <> U+1F53 
U+003C U+0060 U+0057 <> U+1F6B 
U+003C U+0060 U+0077 <> U+1F63 

; (10) `< + letter -> dasia and varia
U+0060 U+003C U+0041 <> U+1F0B 
U+0060 U+003C U+0061 <> U+1F03 
U+0060 U+003C U+0045 <> U+1F1B 
U+0060 U+003C U+0065 <> U+1F13 
U+0060 U+003C U+0048 <> U+1F2B 
U+0060 U+003C U+0068 <> U+1F23 
U+0060 U+003C U+0049 <> U+1F3B 
U+0060 U+003C U+0069 <> U+1F33 
U+0060 U+003C U+004F <> U+1F4B 
U+0060 U+003C U+006F <> U+1F43 
U+0060 U+003C U+0055 <> U+1F5B 
U+0060 U+003C U+0075 <> U+1F53 
U+0060 U+003C U+0057 <> U+1F6B 
U+0060 U+003C U+0077 <> U+1F63 

; (11) ~ + letter -> perispomeni
U+007E U+0041 <> U+0391 U+0342 
U+007E U+0061 <> U+1FB6 
U+007E U+0048 <> U+0397 U+0342 
U+007E U+0068 <> U+1FC6 
U+007E U+0049 <> U+0399 U+0342 
U+007E U+0069 <> U+1FD6 
U+007E U+0055 <> U+03A5 U+0342 
U+007E U+0075 <> U+1FE6 
U+007E U+0057 <> U+03A9 U+0342 
U+007E U+0077 <> U+1FF6 

; (12) >~ + letter -> psili and perispomeni
U+003E U+007E U+0041 <> U+1F0E 
U+003E U+007E U+0061 <> U+1F06 
U+003E U+007E U+0048 <> U+1F2E 
U+003E U+007E U+0068 <> U+1F26 
U+003E U+007E U+0049 <> U+1F3E 
U+003E U+007E U+0069 <> U+1F36 
U+003E U+007E U+0055 <> U+1FCF U+03A5 
U+003E U+007E U+0075 <> U+1F56 
U+003E U+007E U+0057 <> U+1F6E 
U+003E U+007E U+0077 <> U+1F66 

; (13) ~> + letter -> psili and perispomeni
U+007E U+003E U+0041 <> U+1F0E 
U+007E U+003E U+0061 <> U+1F06 
U+007E U+003E U+0048 <> U+1F2E 
U+007E U+003E U+0068 <> U+1F26 
U+007E U+003E U+0049 <> U+1F3E 
U+007E U+003E U+0069 <> U+1F36 
U+007E U+003E U+0055 <> U+1FCF U+03A5 
U+007E U+003E U+0075 <> U+1F56 
U+007E U+003E U+0057 <> U+1F6E 
U+007E U+003E U+0077 <> U+1F66 

; (14) <~ + letter -> dasia and perispomeni
U+003C U+007E U+0041 <> U+1F0F 
U+003C U+007E U+0061 <> U+1F07 
U+003C U+007E U+0048 <> U+1F2F 
U+003C U+007E U+0068 <> U+1F27 
U+003C U+007E U+0049 <> U+1F3F 
U+003C U+007E U+0069 <> U+1F37 
U+003C U+007E U+0055 <> U+1F5F 
U+003C U+007E U+0075 <> U+1F57 
U+003C U+007E U+0057 <> U+1F6F 
U+003C U+007E U+0077 <> U+1F67 

; (15) ~< + letter -> dasia and perispomeni
U+007E U+003C U+0041 <> U+1F0F 
U+007E U+003C U+0061 <> U+1F07 
U+007E U+003C U+0048 <> U+1F2F 
U+007E U+003C U+0068 <> U+1F27 
U+007E U+003C U+0049 <> U+1F3F 
U+007E U+003C U+0069 <> U+1F37 
U+007E U+003C U+0055 <> U+1F5F 
U+007E U+003C U+0075 <> U+1F57 
U+007E U+003C U+0057 <> U+1F6F 
U+007E U+003C U+0077 <> U+1F67 

; (16) letter + | -> ypogegrammeni
U+0041 U+007C <> U+1FBC 
U+0061 U+007C <> U+1FB3 
U+0048 U+007C <> U+1FCC 
U+0068 U+007C <> U+1FC3 
U+0057 U+007C <> U+1FFC 
U+0077 U+007C <> U+1FF3 

; (17) ` + letter + | -> varia and ypogegrammeni
U+0060 U+0061 U+007C <> U+1FB2 
U+0060 U+0068 U+007C <> U+1FC2 
U+0060 U+0077 U+007C <> U+1FF2 

; (18) ' + letter + | -> oxia and ypogegrammeni
U+0027 U+0061 U+007C <> U+1FB2 
U+0027 U+0068 U+007C <> U+1FC2 
U+0027 U+0077 U+007C <> U+1FF2 

; (19) ~ + letter + | -> perispomeni and ypogegrammeni
U+007E U+0061 U+007C <> U+1FB7 
U+007E U+0068 U+007C <> U+1FC7 
U+007E U+0077 U+007C <> U+1FF7 

; (20) > + letter + | -> psili and ypogegrammeni
U+003E U+0041 U+007C <> U+1F88 
U+003E U+0061 U+007C <> U+1F80 
U+003E U+0048 U+007C <> U+1F98 
U+003E U+0068 U+007C <> U+1F90 
U+003E U+0057 U+007C <> U+1FA8 
U+003E U+0077 U+007C <> U+1FA0 

; (21) >` + letter + | -> psili and varia and ypogegrammeni
U+003E U+0060 U+0041 U+007C <> U+1F8A 
U+003E U+0060 U+0061 U+007C <> U+1F82 
U+003E U+0060 U+0048 U+007C <> U+1F9A 
U+003E U+0060 U+0068 U+007C <> U+1F92 
U+003E U+0060 U+0057 U+007C <> U+1FAA 
U+003E U+0060 U+0077 U+007C <> U+1FA2 

; (22) `> + letter + | -> psili and varia and ypogegrammeni
U+0060 U+003E U+0041 U+007C <> U+1F8A 
U+0060 U+003E U+0061 U+007C <> U+1F82 
U+0060 U+003E U+0048 U+007C <> U+1F9A 
U+0060 U+003E U+0068 U+007C <> U+1F92 
U+0060 U+003E U+0057 U+007C <> U+1FAA 
U+0060 U+003E U+0077 U+007C <> U+1FA2 

; (23) >' + letter + | -> psili and oxia and ypogegrammeni
U+003E U+0027 U+0041 U+007C <> U+1F8C 
U+003E U+0027 U+0061 U+007C <> U+1F84 
U+003E U+0027 U+0048 U+007C <> U+1F9C 
U+003E U+0027 U+0068 U+007C <> U+1F94 
U+003E U+0027 U+0057 U+007C <> U+1FAC 
U+003E U+0027 U+0077 U+007C <> U+1FA4 

; (24) '> + letter + | -> psili and oxia and ypogegrammeni
U+0027 U+003E U+0041 U+007C <> U+1F8C 
U+0027 U+003E U+0061 U+007C <> U+1F84 
U+0027 U+003E U+0048 U+007C <> U+1F9C 
U+0027 U+003E U+0068 U+007C <> U+1F94 
U+0027 U+003E U+0057 U+007C <> U+1FAC 
U+0027 U+003E U+0077 U+007C <> U+1FA4 

; (25) < + letter + | -> dasia and ypogegrammeni
U+003C U+0041 U+007C <> U+1F89 
U+003C U+0061 U+007C <> U+1F81 
U+003C U+0048 U+007C <> U+1F99 
U+003C U+0068 U+007C <> U+1F91 
U+003C U+0057 U+007C <> U+1FA9 
U+003C U+0077 U+007C <> U+1FA1 

; (26) <` + letter + | -> dasia and varia and ypogegrammeni
U+003C U+0060 U+0041 U+007C <> U+1F8B 
U+003C U+0060 U+0061 U+007C <> U+1F83 
U+003C U+0060 U+0048 U+007C <> U+1F9B 
U+003C U+0060 U+0068 U+007C <> U+1F93 
U+003C U+0060 U+0057 U+007C <> U+1FAB 
U+003C U+0060 U+0077 U+007C <> U+1FA3 

; (27) `< + letter + | -> dasia and varia and ypogegrammeni
U+0060 U+003C U+0041 U+007C <> U+1F8B 
U+0060 U+003C U+0061 U+007C <> U+1F83 
U+0060 U+003C U+0048 U+007C <> U+1F9B 
U+0060 U+003C U+0068 U+007C <> U+1F93 
U+0060 U+003C U+0057 U+007C <> U+1FAB 
U+0060 U+003C U+0077 U+007C <> U+1FA3 

; (28) <' + letter + | -> dasia and oxia and ypogegrammeni
U+003C U+0027 U+0041 U+007C <> U+1F8D 
U+003C U+0027 U+0061 U+007C <> U+1F85 
U+003C U+0027 U+0048 U+007C <> U+1F9D 
U+003C U+0027 U+0068 U+007C <> U+1F95 
U+003C U+0027 U+0057 U+007C <> U+1FAD 
U+003C U+0027 U+0077 U+007C <> U+1FA5 

; (29) '< + letter + | -> dasia and oxia and ypogegrammeni
U+0027 U+003C U+0041 U+007C <> U+1F8D 
U+0027 U+003C U+0061 U+007C <> U+1F85 
U+0027 U+003C U+0048 U+007C <> U+1F9D 
U+0027 U+003C U+0068 U+007C <> U+1F95 
U+0027 U+003C U+0057 U+007C <> U+1FAD 
U+0027 U+003C U+0077 U+007C <> U+1FA5 

; (30) " + letter -> dialytika
U+0022 U+0049 <> U+03AA 
U+0022 U+0069 <> U+03CA 
U+0022 U+0055 <> U+03AB 
U+0022 U+0075 <> U+03CB 

; (31) "' + letter -> dialytika and oxia
U+0022 U+0027 U+0069 <> U+1FD3 
U+0022 U+0027 U+0075 <> U+1FE3 

; (32) '" + letter -> dialytika and oxia
U+0027 U+0022 U+0069 <> U+1FD3 
U+0027 U+0022 U+0075 <> U+1FE3 

; (33) "` + letter -> dialytika and varia
U+0022 U+0060 U+0069 <> U+1FD2 
U+0022 U+0060 U+0075 <> U+1FE2 

; (34) `" + letter -> dialytika and varia
U+0060 U+0022 U+0069 <> U+1FD2 
U+0060 U+0022 U+0075 <> U+1FE2 

; (35) "~ + letter -> dialytika and perispomeni
U+0022 U+007E U+0069 <> U+1FD7 
U+0022 U+007E U+0075 <> U+1FE7 

; (36) ~" + letter -> dialytika and perispomeni
U+007E U+0022 U+0069 <> U+1FD7 
U+007E U+0022 U+0075 <> U+1FE7 

; (37) rho, medial sigma and punctuation
; >r
U+003E U+0072 <> U+1FE4 
; <R
U+003C U+0052 <> U+1FEC 
; <r
U+003C U+0072 <> U+1FE5 
; medial sigma (sv)
U+0073 U+0076 <> U+03C3 
; question mark
U+003F <> U+037E 
; semicolon
U+003B <> U+0387 

with the command

teckit_compile asciitogreek.map 

Then the following document

\documentclass[a4paper]{article}
\usepackage{fontspec}
\setmainfont{Tempora LGC Unicode}
% \newfontfamily\greekfont{GFS Neohellenic}
\usepackage{polyglossia}
\setmainlanguage[variant=polytonic]{greek}

\XeTeXinputnormalization=1

\newenvironment{transgreek}
  {\catcode`\~=12 \begin{otherlanguage}{greek}%
   \addfontfeature{Mapping=asciitogreek}}
  {\end{otherlanguage}}
\newenvironment{transgreek*}
  {\catcode`\~=12 \begin{otherlanguage*}{greek}%
   \addfontfeature{Mapping=asciitogreek}}
  {\end{otherlanguage*}}

\newcommand{\texttransgreek}{\begingroup
  \catcode`\~=12 \innertexttransgreek}
\newcommand*{\innertexttransgreek}[1]{%
  \begin{transgreek*}#1\end{transgreek*}\endgroup}

\begin{document}

\begin{transgreek}
Th| p'anta dido'ush| ka`i
>apolambano'ush| f'usei <o
pepaideum'enos ka`i a>id'hmwn
l'egei; ((d`os, <`o j'eleis,
>ap'olabe, <`o j'eleic)).
L'egei d`e to~uto o>u
katajrasun'omenos, >all`a
peijarq~wn m'onon ka`i
e>uno~wn a>ut~h|.
\end{transgreek}

\texttransgreek{Th| p'anta dido'ush| ka`i
>apolambano'ush| f'usei <o
pepaideum'enos ka`i a>id'hmwn
l'egei; ((d`os, <`o j'eleis,
>ap'olabe, <`o j'eleic)).
L'egei d`e to~uto o>u
katajrasun'omenos, >all`a
peijarq~wn m'onon ka`i
e>uno~wn a>ut~h|.}

\begin{transgreek}
Γ<<tonos>>

``soma''


0 

abcdefghijklmnopqrstuvwxyz

ABCDEFGHIJKLMNOPQRSTUVWXYZ

abgdezhjiklmnxoprsctupqyw

ABGDEZHJIKLMNXOPRSTUFQYW

1 (bare~ia) `a `e `h `i `o `u `w `A `E `H `I `O `U `W

2 (>oxe~ia) 'a 'e 'h 'i 'o 'u 'w 'A 'E 'H 'I 'O 'U 'W

3 (das`u pne~uma) >a >e >h >i >o >u >w >A >E >H >I >O >U >W

4 (yil'on pne~uma) <a <e <h <i <o <u <w <A <E <H <I <O <U <W

5 >`a >`e >`h >`i >`o >`u >`w >`A >`E >`H >`I >`O >`U >`W

6 `>a `>e `>h `>i `>o `>u `>w `>A `>E `>H `>I `>O `>U `>W

7 >'a >'e >'h >'i >'o >'u >'w >'A >'E >'H >'I >'O >'U >'W

8 '>a '>e '>h '>i '>o '>u '>w '>A '>E '>H '>I '>O '>U '>W

9 >`a >`e >`h >`i >`o >`u >`w >`A >`E >`H >`I >`O >`U >`W

10 `>a `>e `>h `>i `>o `>u `>w `>A `>E `>H `>I `>O `>U `>W

11 (perispwm'enh) ~a ~h ~i ~u ~w ~A ~H ~I ~U ~W

12 >~a >~h >~i >~u >~w >~A >~H >~I >~U >~W

13 ~>a ~>h ~>i ~>u ~>w ~>A ~>H ~>I ~>U ~>W

14 <~a <~h <~i <~u <~w <~A <~H <~I <~U <~W

15 ~<a ~<h ~<i ~<u ~<w ~<A ~<H ~<I ~<U ~<W

16 a| h| w| A| H| W|

17 `a| `h| `w|

18 'a| 'h| 'w|

19 ~a| ~h| ~w|

20 >a| >h| >w| >A| >H| >W| 

21 >`a| >`h| >`w| >`A| >`H| >`W| 

22 `>a| `>h| `>w| `>A| `>H| `>W|

23 >'a| >'h| >'w| >'A| >'H| >'W| 

24 '>a| '>h| '>w| '>A| '>H| '>W|

25 <a| <h| <w| <A| <H| <W| 

26 <`a| <`h| <`w| <`A| <`H| <`W| 

27 `<a| `<h| `<w| `<A| `<H| `<W|

28 <'a| <'h| <'w| <'A| <'H| <'W| 

29 '<a| '<h| '<w| '<A| '<H| '<W|

30 "i "u "I "U

31 "'i "'u

32 '"i '"u

33 "`i "`u

34 `"i `"u

35 "~i "~u

36 ~"i ~"u

37 >r <R <r sv s" ? ;
\end{transgreek}
\end{document}

will show that the transliterization works according with the babel conventions.

enter image description here


If you have only a few greek chars you want to enter you can also use the ^^^^+unicode notation. E.g. for an alpha:

\documentclass{article}
\usepackage{fontspec}
\setmainfont{Arial}
\begin{document}
^^^^03b1

\end{document}

If you’re using GNU/Linux, the Hellenic Polytonic HOWTO (tlgu.carmen.gr/Hellenic_polytonic_HOWTO.html) will be invaluable to you. Note, however, that some of the instructions need updating: at least on Debian systems, one now edits /etc/default/keyboard rather than XF86Config.