> Date: Sat, 28 Apr 2012 20:29:22 +0200 > From: Daniel Krueger <[email protected]> > Cc: [email protected], Sunjoong Lee <[email protected]> > > i think there shouldn't be any transcoding of guile's strings, as > strings are internal representation of characters, no matter how they > are encoded. So the only time when encoding matters is when it passes > it's `internal boundarys', i mean if you write the string to a port or > read from a port or pass it as a string to a foreign library. For the > ports all transcoding is available, and as said, the real > representation of guile strings internally is as utf8, which can't be > changed. The only additional thing i forgot about are bytevectors, if > you convert a string to an explicit representation, but afaik there > you also can give the encoding to use. > > Am I wrong?
You are mostly right, but only "mostly". Experience teaches that sometimes you need to change encoding even inside "the boundaries". One notable example is when the original encoding was determined incorrectly, and the application wants to "re-decode" the string, when its external origin is no longer available. Another example is an application that wants to convert an encoded string into base-64 (or similar) form -- you'll need to encode the string internally first. These kinds of rare, but still important, use cases are the reason why Emacs Lisp has primitives to do encoding and decoding of in-memory strings; as much as Emacs maintainers want to get rid of the related need to support "unibyte strings", they are not going to go away any time soon. IOW, Guile needs a way to represent a string encoded in something other than UTF-8, and convert between UTF-8 and other encodings.
