Added the `return' request to end a macro immediately. It simply

pops iterators from the input stack until a macro iterator is found.

* src/roff/troff/input.cc (input_iterator::is_macro,
macro_iterator::is_macro): New member.
(input_return_boundary): New class to signal an immediate return
to while_request().
(input_stack::add_return_boundary, input_stack::is_return_boundary):
New functions.
(input_stack::clear): Use it.
(input_stack::pop_macro): New function.
(while_request): Use `is_return_boundary()'.
(return_macro_request): New function.
(init_input_requests): Use it.

* src/roff/troff/TODO: Updated.
* NEWS, src/roff/troff/troff.man, man/groff.man: Document it.


* src/roff/troff/input.cc (input_iterator::is_boundary): Minor
cleanup.

6 files changed, 85 insertions, 12 deletions

diff --git a/ChangeLog b/ChangeLog
index c8ffe15e..e67e7a62 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,28 @@
+2001-03-09  Werner LEMBERG  <wl@gnu.org>
+
+	Added the `return' request to end a macro immediately.  It simply
+	pops iterators from the input stack until a macro iterator is found.
+
+	* src/roff/troff/input.cc (input_iterator::is_macro,
+	macro_iterator::is_macro): New member.
+	(input_return_boundary): New class to signal an immediate return
+	to while_request().
+	(input_stack::add_return_boundary, input_stack::is_return_boundary):
+	New functions.
+	(input_stack::clear): Use it.
+	(input_stack::pop_macro): New function.
+	(while_request): Use `is_return_boundary()'.
+	(return_macro_request): New function.
+	(init_input_requests): Use it.
+
+	* src/roff/troff/TODO: Updated.
+	* NEWS, src/roff/troff/troff.man, man/groff.man: Document it.
+
+2001-03-08  Werner LEMBERG  <wl@gnu.org>
+
+	* src/roff/troff/input.cc (input_iterator::is_boundary): Minor
+	cleanup.
+
 2001-03-07  Werner LEMBERG  <wl@gnu.org>
 
 	Make `\B' more rigid.
diff --git a/NEWS b/NEWS
index 61f02633..8f41b4f6 100644
--- a/NEWS
+++ b/NEWS
@@ -25,6 +25,8 @@ o A new command line option for the `man' macros (similar to the `mdoc'
   produce one single, very long page instead of multiple pages.  `-rcR=0'
   will deactivate it.
 
+o The `return' request has been added to return immediately from a macro.
+
 o A new request `nop' (no operation) has been added which is similar to
   `if 1'.  For example,
 
@@ -50,7 +52,7 @@ o The `asciify' request has been extended to `unformat' space characters
 
 o The new `unformat' request is similar to `asciify' but only handles space
   characters and tabs specially if the diversion is reread, retaining font
-  information. This makes it possible to reformat diversions; for example
+  information.  This makes it possible to reformat diversions; for example
   the following
 
     .ll 3i
diff --git a/man/groff.man b/man/groff.man
index 7b23cba4..0d7d3935 100644
--- a/man/groff.man
+++ b/man/groff.man
@@ -1500,6 +1500,9 @@ Remove the definitions of characters
 .REQ .rd prompt
 Read insertion.
 .
+.REQ .return
+Return from a macro.
+.
 .REQ .rj n
 Right justify the next
 .argument n
diff --git a/src/roff/troff/TODO b/src/roff/troff/TODO
index 79d84e29..66605973 100644
--- a/src/roff/troff/TODO
+++ b/src/roff/troff/TODO
@@ -132,6 +132,3 @@ More thorough range checking.
 Provide syntax for octal and hexadecimal numeric constants.  Perhaps
 o#100 and x#7f as per Scheme.  Or perhaps PostScript 16#7f.  Ambiguity
 between whether `c' is treated as digit or scaling indicator.
-
-Request to return from a macro (ie ignore the rest of the current
-input level).
diff --git a/src/roff/troff/input.cc b/src/roff/troff/input.cc
index acfaed24..bcbdb2a1 100644
--- a/src/roff/troff/input.cc
+++ b/src/roff/troff/input.cc
@@ -203,9 +203,10 @@ private:
     { return 0; }
   virtual int next_file(FILE *, const char *) { return 0; }
   virtual void shift(int) {}
-  virtual int is_boundary();
+  virtual int is_boundary() { return 0; }
   virtual int internal_level() { return 0; }
   virtual int is_file() { return 0; }
+  virtual int is_macro() { return 0; }
 };
 
 input_iterator::input_iterator()
@@ -227,11 +228,6 @@ int input_iterator::peek()
   return EOF;
 }
 
-int input_iterator::is_boundary()
-{
-  return 0;
-}
-
 inline int input_iterator::get(node **p)
 {
   return ptr < eptr ? *ptr++ : fill(p);
@@ -242,6 +238,11 @@ public:
   int is_boundary() { return 1; }
 };
 
+class input_return_boundary : public input_iterator {
+public:
+  int is_boundary() { return 2; }
+};
+
 class file_iterator : public input_iterator {
   FILE *fp;
   int lineno;
@@ -400,9 +401,12 @@ public:
   static void end_file();
   static void shift(int n);
   static void add_boundary();
+  static void add_return_boundary();
+  static int is_return_boundary();
   static void remove_boundary();
   static int get_level();
   static void clear();
+  static void pop_macro();
 
   static int limit;
 private:
@@ -475,6 +479,16 @@ void input_stack::add_boundary()
   push(new input_boundary);
 }
 
+void input_stack::add_return_boundary()
+{
+  push(new input_return_boundary);
+}
+
+int input_stack::is_return_boundary()
+{
+  return top->is_boundary() == 2;
+}
+
 void input_stack::remove_boundary()
 {
   assert(top->is_boundary());
@@ -590,7 +604,27 @@ void input_stack::clear()
   }
   // Keep while_request happy.
   for (; nboundaries > 0; --nboundaries)
-    add_boundary();
+    add_return_boundary();
+}
+
+void input_stack::pop_macro()
+{
+  int nboundaries = 0;
+  int is_macro = 0;
+  do {
+    if (top->next == &nil_iterator)
+      break;
+    if (top->is_boundary())
+      nboundaries++;
+    is_macro = top->is_macro();
+    input_iterator *tem = top;
+    top = top->next;
+    level--;
+    delete tem;
+  } while (!is_macro);
+  // Keep while_request happy.
+  for (; nboundaries > 0; --nboundaries)
+    add_return_boundary();
 }
 
 void backtrace_request()
@@ -1988,6 +2022,12 @@ void exit_request()
     exit_troff();
 }
 
+void return_macro_request()
+{
+  input_stack::pop_macro();
+  tok.next();
+}
+
 void end_macro()
 {
   end_macro_name = get_name();
@@ -2903,6 +2943,7 @@ public:
   int nargs() { return argc; }
   void add_arg(const macro &m);
   void shift(int n);
+  int is_macro() { return 1; }
 };
 
 input_iterator *macro_iterator::get_arg(int i)
@@ -4589,7 +4630,7 @@ void while_request()
 	break;
       }
       process_input_stack();
-      if (while_break_flag) {
+      if (while_break_flag || input_stack::is_return_boundary()) {
 	while_break_flag = 0;
 	break;
       }
@@ -6301,6 +6342,7 @@ void init_input_requests()
   init_request("tm1", terminal1);
   init_request("tmc", terminal_continue);
   init_request("ex", exit_request);
+  init_request("return", return_macro_request);
   init_request("em", end_macro);
   init_request("blm", blank_line_macro);
   init_request("tr", translate);
diff --git a/src/roff/troff/troff.man b/src/roff/troff/troff.man
index 7b57ee08..5f54e42a 100644
--- a/src/roff/troff/troff.man
+++ b/src/roff/troff/troff.man
@@ -1317,6 +1317,10 @@ This undoes the effect of a
 .B char
 request.
 .TP
+.B .return
+Within a macro, return immediately.
+No effect otherwise.
+.TP
 .B .rj
 .TQ
 .BI .rj\  n