fmt: accept new --goal=WIDTH (-g) option

Accept -g for BSD/Plan9 compatibility.
* NEWS (New features): Mention it.
* tests/fmt/goal-option: New test.
* tests/fmt/long-line: Rename from tests/fmt-long-line.
* tests/fmt/base: Rename from tests/misc/fmt.
* doc/coreutils.texi: Document it.
* src/fmt.c (main): Accept the new option
(check_for_goals): new function to implement the operands
Based on BSD's and Plan-9's fmt programs.

NEWS

@@ -2,6 +2,10 @@ GNU coreutils NEWS                                    -*- outline -*-
 
 * Noteworthy changes in release ?.? (????-??-??) [?]
 
+** New features
+
+  fmt now accepts the --goal=WIDTH (-g) option.
+
 ** Changes in behavior
 
   cp --attributes-only no longer truncates any existing destination file,

doc/coreutils.texi

@@ -2203,9 +2203,15 @@ between sentences to two spaces.
 @opindex -@var{width}
 @opindex -w
 @opindex --width
-Fill output lines up to @var{width} characters (default 75).  @command{fmt}
-initially tries to make lines about 7% shorter than this, to give it
-room to balance line lengths.
+Fill output lines up to @var{width} characters (default 75 or @var{goal}
+plus 10, if @var{goal} is provided).
+
+@itemx -g @var{goal}
+@itemx --goal=@var{goal}
+@opindex -g
+@opindex --goal
+@command{fmt} initially tries to make lines @var{goal} characters wide.
+By default, this is 7% shorter than @var{width}.
 
 @item -p @var{prefix}
 @itemx --prefix=@var{prefix}

src/fmt.c

@@ -68,7 +68,7 @@ typedef long int COST;
 #define SQR(n)		((n) * (n))
 #define EQUIV(n)	SQR ((COST) (n))
 
-/* Cost of a filled line n chars longer or shorter than best_width.  */
+/* Cost of a filled line n chars longer or shorter than goal_width.  */
 #define SHORT_COST(n)	EQUIV ((n) * 10)
 
 /* Cost of the difference between adjacent filled lines.  */
@@ -201,7 +201,7 @@ static int prefix_lead_space;
 static int prefix_length;
 
 /* The preferred width of text lines, set to LEEWAY % less than max_width.  */
-static int best_width;
+static int goal_width;
 
 /* Dynamic variables.  */
 
@@ -286,6 +286,7 @@ Mandatory arguments to long options are mandatory for short options too.\n\
   -t, --tagged-paragraph    indentation of first line different from second\n\
   -u, --uniform-spacing     one space between words, two after sentences\n\
   -w, --width=WIDTH         maximum line width (default of 75 columns)\n\
+  -g, --goal=WIDTH          goal width (default of 93% of width)\n\
 "), stdout);
       fputs (HELP_OPTION_DESCRIPTION, stdout);
       fputs (VERSION_OPTION_DESCRIPTION, stdout);
@@ -308,6 +309,7 @@ static struct option const long_options[] =
   {"tagged-paragraph", no_argument, NULL, 't'},
   {"uniform-spacing", no_argument, NULL, 'u'},
   {"width", required_argument, NULL, 'w'},
+  {"goal", required_argument, NULL, 'g'},
   {GETOPT_HELP_OPTION_DECL},
   {GETOPT_VERSION_OPTION_DECL},
   {NULL, 0, NULL, 0},
@@ -319,6 +321,7 @@ main (int argc, char **argv)
   int optchar;
   bool ok = true;
   char const *max_width_option = NULL;
+  char const *goal_width_option = NULL;
 
   initialize_main (&argc, &argv);
   set_program_name (argv[0]);
@@ -344,7 +347,7 @@ main (int argc, char **argv)
       argc--;
     }
 
-  while ((optchar = getopt_long (argc, argv, "0123456789cstuw:p:",
+  while ((optchar = getopt_long (argc, argv, "0123456789cstuw:p:g:",
                                  long_options, NULL))
          != -1)
     switch (optchar)
@@ -376,6 +379,10 @@ main (int argc, char **argv)
         max_width_option = optarg;
         break;
 
+      case 'g':
+        goal_width_option = optarg;
+        break;
+
       case 'p':
         set_prefix (optarg);
         break;
@@ -398,7 +405,22 @@ main (int argc, char **argv)
       max_width = tmp;
     }
 
-  best_width = max_width * (2 * (100 - LEEWAY) + 1) / 200;
+  if (goal_width_option)
+    {
+      /* Limit goal_width to max_width.  */
+      unsigned long int tmp;
+      if (! (xstrtoul (goal_width_option, NULL, 10, &tmp, "") == LONGINT_OK
+             && tmp <= max_width))
+        error (EXIT_FAILURE, 0, _("invalid width: %s"),
+               quote (goal_width_option));
+      goal_width = tmp;
+      if (max_width_option == NULL)
+        max_width = goal_width + 10;
+    }
+  else
+    {
+      goal_width = max_width * (2 * (100 - LEEWAY) + 1) / 200;
+    }
 
   if (optind == argc)
     fmt (stdin);
@@ -924,7 +946,7 @@ line_cost (WORD *next, int len)
 
   if (next == word_limit)
     return 0;
-  n = best_width - len;
+  n = goal_width - len;
   cost = SHORT_COST (n);
   if (next->next_break != word_limit)
     {

tests/Makefile.am

@@ -140,6 +140,9 @@ TESTS =						\
   chgrp/no-x					\
   chgrp/posix-H					\
   chgrp/recurse					\
+  fmt/base					\
+  fmt/long-line					\
+  fmt/goal-option				\
   misc/env					\
   misc/ptx					\
   misc/test					\
@@ -188,8 +191,6 @@ TESTS =						\
   misc/expr					\
   misc/factor					\
   misc/false-status				\
-  misc/fmt					\
-  misc/fmt-long-line				\
   misc/fold					\
   misc/groups-dash				\
   misc/groups-version				\

tests/fmt/goal-option

@@ -0,0 +1,56 @@
+#!/bin/sh
+# Exercise the fmt -g option.
+
+# Copyright (C) 2012 Free Software Foundation, Inc.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+. "${srcdir=.}/init.sh"; path_prepend_ ../src
+print_ver_ fmt
+
+cat <<\_EOF_ > base || fail=1
+
+@command{fmt} prefers breaking lines at the end of a sentence, and tries to
+avoid line breaks after the first word of a sentence or before the last word
+of a sentence.  A @dfn{sentence break} is defined as either the end of a
+paragraph or a word ending in any of @samp{.?!}, followed by two spaces or end
+of line, ignoring any intervening parentheses or quotes.  Like @TeX{},
+@command{fmt} reads entire ''paragraphs'' before choosing line breaks; the
+algorithm is a variant of that given by
+Donald E. Knuth and Michael F. Plass
+in ''Breaking Paragraphs Into Lines'',
+@cite{Software---Practice & Experience}
+@b{11}, 11 (November 1981), 1119--1184.
+_EOF_
+
+fmt -g 60 -w 72 base > out || fail=1
+
+cat <<\_EOF_ > exp
+
+@command{fmt} prefers breaking lines at the end of a sentence,
+and tries to avoid line breaks after the first word of a sentence
+or before the last word of a sentence.  A @dfn{sentence break}
+is defined as either the end of a paragraph or a word ending
+in any of @samp{.?!}, followed by two spaces or end of line,
+ignoring any intervening parentheses or quotes.  Like @TeX{},
+@command{fmt} reads entire ''paragraphs'' before choosing line
+breaks; the algorithm is a variant of that given by Donald
+E. Knuth and Michael F. Plass in ''Breaking Paragraphs Into
+Lines'', @cite{Software---Practice & Experience} @b{11}, 11
+(November 1981), 1119--1184.
+_EOF_
+
+compare exp out || fail=1
+
+Exit $fail