[erlang-questions] cookbook entry #1 - unicode/UTF-8 strings
Tue Oct 25 06:26:26 CEST 2011
>> Cookbook Question:
>> I have often seen the words "UTF-8 string" used in sentences like
>> "Java has UTF-8 strings". What does this mean when applied to Erlang?
Minor note: it means very little when applied to Java and less of that
is actually true.
- Java *source* code, including strings, may be encoded in various
ways, including UTF-8.
- The String *class* in Java is *NOT* based on UTF-8 but on UTF-16.
- There is no reason in principle why Java _couldn't_ have a UTF-8
string type, but there doesn't happen to be one in java.lang.*
or java.util.* (I rolled my own Latin1 string class for some
>> In Erlang strings are syntactic sugar for "lists of integers"
In Java strings are syntactic sugar for "slices of arrays of 16-bit integers".
>> Imagine the string "10(Euro)" - (Euro) is the glyph representing the
>> Euro currency symbol.
>> The term "UF8-string" representing "10(euro)" in Erlang could
>> mean one of two things:
>> Either a) [49,48,8364] (ie its a list of three unicode
For "integer" read "codepoint".
Dealing with Unicode *codepoints* in Erlang is tolerably straightforward;
the difficulties are
- dealing with external *encodings*
- dealing with the *semantics* of Unicode, like the way that
different sequences of codepoints may represent the same
sequence of characters, so that list equality and string equality
are arguably different things.
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