diff options
Diffstat (limited to 'doc/re_syntax.n')
| -rw-r--r-- | doc/re_syntax.n | 29 |
1 files changed, 16 insertions, 13 deletions
diff --git a/doc/re_syntax.n b/doc/re_syntax.n index 8701641..a53f58b 100644 --- a/doc/re_syntax.n +++ b/doc/re_syntax.n @@ -359,39 +359,42 @@ horizontal tab, as in C .TP \fB\eu\fIwxyz\fR . -(where \fIwxyz\fR is exactly four hexadecimal digits) the Unicode +(where \fIwxyz\fR is one up to four hexadecimal digits) the Unicode character \fBU+\fIwxyz\fR in the local byte ordering .TP \fB\eU\fIstuvwxyz\fR . -(where \fIstuvwxyz\fR is exactly eight hexadecimal digits) reserved -for a somewhat-hypothetical Unicode extension to 32 bits +(where \fIstuvwxyz\fR is one up to eight hexadecimal digits) reserved +for a Unicode extension up to 21 bits. The digits are parsed until the +first non-hexadecimal character is encountered, the maximun of eight +hexadecimal digits are reached, or an overflow would occur in the maximum +value of \fBU+\fI10ffff\fR. .TP \fB\ev\fR . vertical tab, as in C are all available. .TP -\fB\ex\fIhhh\fR +\fB\ex\fIhh\fR . -(where \fIhhh\fR is any sequence of hexadecimal digits) the character -whose hexadecimal value is \fB0x\fIhhh\fR (a single character no -matter how many hexadecimal digits are used). +(where \fIhh\fR is one or two hexadecimal digits) the character +whose hexadecimal value is \fB0x\fIhh\fR. .TP \fB\e0\fR . the character whose value is \fB0\fR .TP +\fB\e\fIxyz\fR +. +(where \fIxyz\fR is exactly three octal digits, and is not a \fIback +reference\fR (see below)) the character whose octal value is +\fB0\fIxyz\fR. The first digit must be in the range 0-3, otherwise +the two-digit form is assumed. +.TP \fB\e\fIxy\fR . (where \fIxy\fR is exactly two octal digits, and is not a \fIback reference\fR (see below)) the character whose octal value is \fB0\fIxy\fR -.TP -\fB\e\fIxyz\fR -. -(where \fIxyz\fR is exactly three octal digits, and is not a back -reference (see below)) the character whose octal value is -\fB0\fIxyz\fR .RE .PP Hexadecimal digits are |