A Programmer’s Introduction to Unicode

Re:A Programmer’s Introduction to Unicode by Manishearth on Saturday March 04, 2017 @02:13PM (#13792378)

A bunch of characters are prepended combining marks (so lookahead doesn't quite work)

    0600..0605    ; Prepend # Cf   [6] ARABIC NUMBER SIGN..ARABIC NUMBER MARK ABOVE
    06DD          ; Prepend # Cf       ARABIC END OF AYAH
    070F          ; Prepend # Cf       SYRIAC ABBREVIATION MARK
    08E2          ; Prepend # Cf       ARABIC DISPUTED END OF AYAH
    0D4E          ; Prepend # Lo       MALAYALAM LETTER DOT REPH
    110BD         ; Prepend # Cf       KAITHI NUMBER SIGN
    111C2..111C3  ; Prepend # Lo   [2] SHARADA SIGN JIHVAMULIYA..SHARADA SIGN UPADHMANIYA

While Unicode-specced grapheme boundaries (UAX 29) do not deal with these, Indic scripts have an "infix" combining mark that takes two regular code points on either side to form a consonant cluster. (Also, Hangul is based on conjoining code points where none of the code points is really a "combiner", they're all equally "regular" characters)

I suspect the actual answer to your question is "historical accident". But, the dead key argument doesn't quite hold -- I can equally ask why keyboard dead keys aren't typed after the character.

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Re:A Programmer’s Introduction to Unicode by kps on Saturday March 04, 2017 @03:35PM (#13792816)

  > I can equally ask why keyboard dead keys aren't typed after the character.

That does have an answer: keyboards predate electronics. A mechanical typewriter key press slams a type bar into the ribbon, and on the way back, catches a mechanism that releases the carriage (which is pulled along by a spring) for one column. A dead key is very simple; it just omits the catch. A postfix dead key would be more complicated, since it would have to add an early backspace action, and harder to press, since backspacing pulls against the carriage spring.

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Re:A Programmer’s Introduction to Unicode by Manishearth on Tuesday March 07, 2017 @02:49AM (#13808918)

This is pretty cool and interesting. Thanks!

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