* doc/groff.texinfo, src/roff/troff/troff.man: Add documentation

of the `substring' request.
* src/roff/troff/TODO, NEWS: Updated.

5 files changed, 45 insertions, 8 deletions

diff --git a/ChangeLog b/ChangeLog
index 13866bf3..951dfe4d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2000-02-11  Werner LEMBERG  <wl@gnu.org>
+
+	* doc/groff.texinfo, src/roff/troff/troff.man: Add documentation
+	of the `substring' request.
+	* src/roff/troff/TODO, NEWS: Updated.
+
 2000-02-09  Werner LEMBERG  <wl@gnu.org>
 
 	* src/roff/groff/groff.man: Added an example.
diff --git a/NEWS b/NEWS
index f0c69438..29c3026b 100644
--- a/NEWS
+++ b/NEWS
@@ -41,8 +41,8 @@ available to get the bounding box of a PostScript image file.  The values
 `llx', `lly', `urx', and `ury'.  Consequently, .PSPIC has been adapted to
 use the new request, and the psbb program has been removed.
 
-A new number predefined writable number register, `year', has been added.
-It contains the current year.
+A new predefined writable number register, `year', has been added.  It
+contains the current year.
 
 A new read-only register, `.Y', has been added.  It contains the revision
 number of the groff package.
@@ -53,7 +53,9 @@ font `foo' is undefined:
   .B bold text
   normal text \f[foo]bar\fP normal text
 
-Previously, the text after \fP has appeared as bold.
+Previously, the text after \fP appeared as bold.
+
+The `substring' request is not new, but hasn't been documented before.
 
 The macro files `tmac.a4' (for specifying A4 paper format) and `tmac.trace'
 (a debugging aid) are now installed also.
diff --git a/doc/groff.texinfo b/doc/groff.texinfo
index 344e6443..d02126f0 100644
--- a/doc/groff.texinfo
+++ b/doc/groff.texinfo
@@ -3580,7 +3580,7 @@ string-valued register.
 
 @findex ds
 Groff has string variables, which are entirely for user convenience
-(i.e. there are no builtin strings) They are defined via the
+(i.e. there are no builtin strings).  They are defined via the
 @code{ds} request.
 
 @example
@@ -3588,7 +3588,7 @@ Groff has string variables, which are entirely for user convenience
 @end example
 
 @findex \*
-The are interpolated, or expanded in-place, via the @code{\*} escape:
+They are interpolated, or expanded in-place, via the @code{\*} escape:
 
 @example
 The \*(UX Operating System
@@ -3650,6 +3650,16 @@ of text are on these \
 next several lines
 @end example
 
+@findex substring
+@cindex substrings
+@code{.substring xx n1 [n2]}
+Replace the string in register@w{ }xx with the substring defined by the
+indices n1 and@w{ }n2.  The first character in the string has index one.
+If n2 is omitted, it is taken to be equal to the string's length.  If
+the index value n1 or n2 is negative or zero, it will be counted from
+the end of the string, going backwards: The last character has index@w{
+}0, the character before the last character has index@w{ }-1, etc.
+
 @findex rn
 @code{rn}
 
@@ -3952,7 +3962,7 @@ request can make a macro have more than one name.
 This would be called as
 
 @example
-.vl $Id: groff.texinfo,v 1.1 2000/02/06 09:39:38 wlemb Exp $
+.vl $Id: groff.texinfo,v 1.2 2000/02/11 16:26:45 wlemb Exp $
 @end example
 
 
diff --git a/src/roff/troff/TODO b/src/roff/troff/TODO
index 7e511235..2f2ecbf3 100644
--- a/src/roff/troff/TODO
+++ b/src/roff/troff/TODO
@@ -105,7 +105,7 @@ optionally print the contents of a macro.
 Provide some way to round numbers to multiples of the current
 horizontal or vertical resolution.
 
-Better string-processing support (substring, length, search).
+Better string-processing support (length, search).
 
 Generalized ligatures.
 
diff --git a/src/roff/troff/troff.man b/src/roff/troff/troff.man
index 82d373ba..25053376 100644
--- a/src/roff/troff/troff.man
+++ b/src/roff/troff/troff.man
@@ -1100,7 +1100,7 @@ command looks for a
 .B %%BoundingBox
 comment to extract the bounding box values.
 After a successful call, the coordinates (in PostScript units) of the lower
-left and upper right edge can be found in the registers
+left and upper right corner can be found in the registers
 .BR \en[llx] ,
 .BR \en[lly] ,
 .BR \en[urx] ,
@@ -1237,6 +1237,25 @@ The styles command in the
 file controls which font positions
 (if any) are initially associated with styles rather than fonts.
 .TP
+.BI .substring\  xx\ n1\  [ n2 ]
+Replace the string in register
+.I xx
+with the substring defined by the indices
+.I n1
+and
+.IR n2 .
+The first character in the string has index one.
+If
+.I n2
+is omitted, it is taken to be equal to the string's length.  If the
+index value
+.I n1
+or
+.I n2
+is negative or zero, it will be counted from the end of the string,
+going backwards: The last character has index 0, the character before
+the last character has index -1, etc.
+.TP
 .BI .tkf\  f\ s1\ n1\ s2\ n2
 Enable track kerning for font
 .IR f .