A new request `length' is available which returns the length of a

string in a number register:

* src/roff/troff/input.cc (length_macro): Implement it.
* src/roff/troff/input.cc (init_input_requests): Register it.


* src/roff/troff/troff.man, doc/groff.texinfo: Document `length'
request.

6 files changed, 70 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index 951dfe4d..067de146 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,7 +1,19 @@
+2000-02-11  Abramo Bagnara  <abramo@alsa-project.org>
+
+	A new request `length' is available which returns the length of a
+	string in a number register:
+
+	* src/roff/troff/input.cc (length_macro): Implement it.
+	* src/roff/troff/input.cc (init_input_requests): Register it.
+
 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/troff.man, doc/groff.texinfo: Document `length'
+	request.
+
 	* src/roff/troff/TODO, NEWS: Updated.
 
 2000-02-09  Werner LEMBERG  <wl@gnu.org>
diff --git a/NEWS b/NEWS
index 29c3026b..d5669fe8 100644
--- a/NEWS
+++ b/NEWS
@@ -57,6 +57,9 @@ Previously, the text after \fP appeared as bold.
 
 The `substring' request is not new, but hasn't been documented before.
 
+A new request `length' computes the length of a string and returns it in
+a number register.
+
 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 d02126f0..902ce9a2 100644
--- a/doc/groff.texinfo
+++ b/doc/groff.texinfo
@@ -3660,6 +3660,13 @@ 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 length
+@cindex length of a string
+@cindex string, length of
+@code{.length xx string}
+Compute the length of string and return it in the number register@w{ }xx
+(which is not necessarily defined before).
+
 @findex rn
 @code{rn}
 
@@ -3962,7 +3969,7 @@ request can make a macro have more than one name.
 This would be called as
 
 @example
-.vl $Id: groff.texinfo,v 1.2 2000/02/11 16:26:45 wlemb Exp $
+.vl $Id: groff.texinfo,v 1.3 2000/02/11 22:17:10 wlemb Exp $
 @end example
 
 
diff --git a/src/roff/troff/TODO b/src/roff/troff/TODO
index 2f2ecbf3..1852aafc 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 (length, search).
+Better string-processing support (search).
 
 Generalized ligatures.
 
diff --git a/src/roff/troff/input.cc b/src/roff/troff/input.cc
index a4565904..7647bc62 100644
--- a/src/roff/troff/input.cc
+++ b/src/roff/troff/input.cc
@@ -3512,6 +3512,44 @@ void substring_macro()
   skip_line();
 }
 
+void length_macro()
+{
+  symbol ret;
+  ret = get_name(1);
+  if (ret.is_null()) {
+    skip_line();
+    return;
+  }
+  int c;
+  node *n;
+  if (tok.newline())
+    c = '\n';
+  else if (tok.tab())
+    c = '\t';
+  else if (!tok.space()) {
+    error("bad string definition");
+    skip_line();
+    return;
+  }
+  else
+    c = get_copy(&n);
+  while (c == ' ')
+    c = get_copy(&n);
+  if (c == '"')
+    c = get_copy(&n);
+  int len = 0;
+  while (c != '\n' && c != EOF) {
+    ++len;
+    c = get_copy(&n);
+  }
+  tok.next();
+  reg *r = (reg*)number_reg_dictionary.lookup(ret);
+  if (r)
+    r->set_value(len);
+  else
+    set_number_reg(ret, len);
+}
+
 void asciify_macro()
 {
   symbol s = get_name(1);
@@ -5832,6 +5870,7 @@ void init_input_requests()
   init_request("backtrace", backtrace_request);
   init_request("chop", chop_macro);
   init_request("substring", substring_macro);
+  init_request("length", length_macro);
   init_request("asciify", asciify_macro);
   init_request("warn", warn_request);
   init_request("open", open_request);
diff --git a/src/roff/troff/troff.man b/src/roff/troff/troff.man
index 25053376..0dc4e306 100644
--- a/src/roff/troff/troff.man
+++ b/src/roff/troff/troff.man
@@ -1047,6 +1047,13 @@ If
 .I n
 is non-zero or missing, enable pairwise kerning, otherwise disable it.
 .TP
+.BI .length\  xx\ string
+Compute the length of
+.I string
+and return it in the number register
+.I xx
+(which is not necessarily defined before).
+.TP
 .BI .mso\  file
 The same as the
 .B so