Locale support. I'm checking this in to clean up fall-out in-tree, but

it looks pretty good.  Basically, the -Tlocale option propogates into
term_ascii.c, where we set locale-specific console call-backs IFF (1)
setlocale() works; (2) locale support is compiled in (see Makefile for
-DUSE_WCHAR); (3) the internal structure of wchar_t maps directly to
Unicode codepoints as defined by __STDC_ISO_10646__; and (4) the console
supports multi-byte characters.

To date, this configuration only supports GNU/Linux.  OpenBSD doesn't
export __STDC_ISO_10646__ although I'm told by stsp@openbsd.org that it
should (it has the correct map).  Apparently FreeBSD is the same way.
NetBSD?  Don't know.  Apple also supports this, but doesn't define the
macro.  Special-casing!

Benchmark: -Tlocale incurs less than 0.2 factor overhead when run
through several thousand manuals when UTF8 output is enabled.  Native
mode (whether directly -Tascii or through no locale or whatever) is
UNCHANGED: the function callbacks are the same as before.

Note.  If the underlying system does NOT support STDC_ISO_10646, there
is a "slow" version possible with iconv or other means of flipping from
a Unicode codepoint to a wchar_t.

1 files changed, 20 insertions, 1 deletions

diff --git a/mandoc.1 b/mandoc.1
index 9626d171..c7c6fcc8 100644
--- a/mandoc.1
+++ b/mandoc.1
@@ -158,6 +158,12 @@ utility accepts the following
 .Fl T
 arguments, which correspond to output modes:
 .Bl -tag -width Ds
+.It Fl T Ns Cm locale
+This option encodes output characters using the current
+.Xr locale 1
+configuration.
+See
+.Sx Locale Output .
 .It Fl T Ns Cm ascii
 Produce 7-bit ASCII output.
 This is the default.
@@ -189,6 +195,16 @@ See
 .Pp
 If multiple input files are specified, these will be processed by the
 corresponding filter in-order.
+.Ss Locale Output
+Locale-depending output encoding is triggered with
+.Fl T Ns Cm locale .
+This option is not available on all systems: systems without locale
+support, or those whose internal representation is not natively UCS-4,
+will fall back to
+.Fl T Ns Cm ascii .
+See
+.Sx ASCII Output
+for font style specification and available command-line arguments.
 .Ss ASCII Output
 Output produced by
 .Fl T Ns Cm ascii ,
@@ -209,6 +225,9 @@ Emboldened characters are rendered as
 The special characters documented in
 .Xr mandoc_char 7
 are rendered best-effort in an ASCII equivalent.
+If no equivalent is found,
+.Sq \&?
+is used instead.
 .Pp
 Output width is limited to 78 visible columns unless literal input lines
 exceed this limit.
@@ -460,7 +479,7 @@ Each input and output format is separately noted.
 .Ss ASCII Compatibility
 .Bl -bullet -compact
 .It
-Unicode codepoints specified with
+Unrenderable unicode codepoints specified with
 .Sq \e[uNNNN]
 escapes are printed as
 .Sq \&?