Bruno Haible <[email protected]> writes: >> > The next modules will have a higher-level API, I imagine. You're welcome >> > to discuss the new API with me, before you implement it. >> >> I am thinking of something like: >> size_t u<#>_grapheme_len (const uint<#>_t *s, size_t n); >> which would return the number of units in the first grapheme >> cluster in S. > > "grapheme" or "grapheme cluster"? I'm a bit confused: The Unicode 3.0 > book uses the term "grapheme" to denote the entity that users consider > to be a single character, but UAX #29 nowadays calls it "grapheme cluster".
I am being a little sloppy with terminology. My take-away from the Unicode glossary definitions is that a "grapheme" is a user-perceived character, and a "grapheme cluster" is the sequence of code points that make up a grapheme. If I am correct about that, then properly this would be a grapheme cluster. > OK for this kind of API, if the grapheme break determination is context free > (unlike the word break determination). Can you confirm that? Yes, grapheme cluster break determination looks only at the previous and next code point. The uc_is_grapheme_cluster_break function is sufficient to find breakpoints. > A function for iterating backwards, i.e. returning the grapheme > bounds before a certain point in a string, would be useful too > then. Like u#_next and u#_prev in <unistr.h>: > > const uint#_t * u#_grapheme_next (const uint#_t *s, const uint#_t *end); > const uint#_t * u#_grapheme_prev (const uint#_t *s, const uint#_t *start); > > And for convenience, I would suggest an API that operates on an > entire string, like done for the word breaks: > > /* Determine the grapheme [cluster?] break points in S, and store the result > at p[0..n-1]. > p[i] = 1 means that there is a grapheme [cluster?] boundary between s[i-1] > and s[i]. > p[i] = 0 means that s[i-1] and s[i] must not be separated. > */ > extern void > u8_grapheme_breaks (const uint8_t *s, size_t n, char *p); > extern void > u16_grapheme_breaks (const uint16_t *s, size_t n, char *p); > extern void > u32_grapheme_breaks (const uint32_t *s, size_t n, char *p); > extern void > ulc_grapheme_breaks (const char *s, size_t n, char *p); OK, I'll look at writing those functions too. Thanks, Ben. -- Ben Pfaff http://benpfaff.org
