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(read_escape): Provide a Unicode character escape syntax; \u followed by

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exactly four or \U followed by exactly eight hex digits in a comment or
string is read as a Unicode character with that code point.
This commit is contained in:
Eli Zaretskii 2006-06-09 18:22:30 +00:00
parent a9ab79a844
commit 71b169b8c4
1 changed files with 49 additions and 0 deletions
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49
src/lread.c
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@ -1764,6 +1764,9 @@ read_escape (readcharfun, stringp, byterep)
int *byterep;
{
register int c = READCHAR;
/* \u allows up to four hex digits, \U up to eight. Default to the
behaviour for \u, and change this value in the case that \U is seen. */
int unicode_hex_count = 4;
*byterep = 0;
@ -1928,6 +1931,52 @@ read_escape (readcharfun, stringp, byterep)
return i;
}
case 'U':
/* Post-Unicode-2.0: Up to eight hex chars. */
unicode_hex_count = 8;
case 'u':
/* A Unicode escape. We only permit them in strings and characters,
not arbitrarily in the source code, as in some other languages. */
{
int i = 0;
int count = 0;
Lisp_Object lisp_char;
struct gcpro gcpro1;
while (++count <= unicode_hex_count)
{
c = READCHAR;
/* isdigit(), isalpha() may be locale-specific, which we don't
want. */
if (c >= '0' && c <= '9') i = (i << 4) + (c - '0');
else if (c >= 'a' && c <= 'f') i = (i << 4) + (c - 'a') + 10;
else if (c >= 'A' && c <= 'F') i = (i << 4) + (c - 'A') + 10;
else
{
error ("Non-hex digit used for Unicode escape");
break;
}
}
GCPRO1 (readcharfun);
lisp_char = call2(intern("decode-char"), intern("ucs"),
make_number(i));
UNGCPRO;
if (EQ(Qnil, lisp_char))
{
/* This is ugly and horrible and trashes the user's data. */
XSETFASTINT (i, MAKE_CHAR (charset_katakana_jisx0201,
34 + 128, 46 + 128));
return i;
}
else
{
return XFASTINT (lisp_char);
}
}
default:
if (BASE_LEADING_CODE_P (c))
c = read_multibyte (c, readcharfun);