in reply to The “real length" of UTF8 strings
For any UTF8 string, we have four "lengths":
- the length in codepoints:
(忍 Guimarăes)perl -C63 -MDevel::Peek -Mutf8 -le '$_="(\x{5fcd} Guimarăes)"; Dump($_ +); print length($_); print' SV = PV(0x8154b00) at 0x8153bd4 REFCNT = 1 FLAGS = (POK,pPOK,UTF8) PV = 0x8170460 "(\345\277\215 Guimar\303\243es)"\0 [UTF8 "(\x{5fcd} +Guimar\x{e3}es)"] CUR = 16 LEN = 20 13 - the length in graphemes (the "a" is one, the composing "~" is another):
(忍 Guimarães)perl -C63 -MDevel::Peek -Mutf8 -MUnicode::Normalize -le '$_="(\x{5fcd} + Guimarăes)"; $_ = NFD $_; Dump($_); print length($_); print' SV = PV(0x8154b00) at 0x8153bd4 REFCNT = 1 FLAGS = (POK,pPOK,UTF8) PV = 0x816feb8 "(\345\277\215 Guimara\314\203es)"\0 [UTF8 "(\x{5fcd} + Guimara\x{303}es)"] CUR = 17 LEN = 20 14 - the length in columns of text used (the string has one wide character):
(忍 Guimarăes)perl -C63 -MDevel::Peek -Mutf8 -mText::CharWidth=mbswidth -le '$_="(\x +{5fcd} Guimarăes)"; Dump($_); print mbswidth($_); print' SV = PV(0x8154b00) at 0x8153bd4 REFCNT = 1 FLAGS = (POK,pPOK,UTF8) PV = 0x8170460 "(\345\277\215 Guimar\303\243es)"\0 [UTF8 "(\x{5fcd} +Guimar\x{e3}es)"] CUR = 16 LEN = 20 14 - the length in bytes of the string (notice I didn't print the string after the encode):
perl -C63 -MDevel::Peek -Mutf8 -mEncode=encode_utf8 -le '$_="(\x{5fcd} + Guimarăes)"; Dump($_); print length(encode_utf8 $_)' SV = PV(0x8154b00) at 0x8153bd4 REFCNT = 1 FLAGS = (POK,pPOK,UTF8) PV = 0x8170460 "(\345\277\215 Guimar\303\243es)"\0 [UTF8 "(\x{5fcd} +Guimar\x{e3}es)"] CUR = 16 LEN = 20 16
[]s, HTH, Massa (κς,πμ,πλ)
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