[groff] 25/30: [neqn]: Recognize `-h`, `--help` options.

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit 2bc287d9a4e41ae55f0bcc3443072eba6cfdad93
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Sat Dec 21 19:28:42 2024 -0600

    [neqn]: Recognize `-h`, `--help` options.
    
    * src/preproc/eqn/neqn.sh: Handle `-h` and `--help` options: display a
      usage message to the standard output and exit with a successful
      status.
    
    Also annotate oddities in shell syntax.
    
    Also work around Solaris 10 /bin/sh brain damage.
    
    Also add editor aid comments.
---
 ChangeLog               |  6 +++++
 src/preproc/eqn/neqn.sh | 59 +++++++++++++++++++++++++++++++++++++++++--------
 2 files changed, 56 insertions(+), 9 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index eadd68e15..84a4a7570 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2024-12-21  G. Branden Robinson <g.branden.robinson@gmail.com>
+
+       * src/preproc/eqn/neqn.sh: Handle `-h` and `--help` options:
+       display a usage message to the standard output and exit with a
+       successful status.
+
 2024-12-21  G. Branden Robinson <g.branden.robinson@gmail.com>
 
        * src/include/lf.h: Include "stringclass.h" header file, since
diff --git a/src/preproc/eqn/neqn.sh b/src/preproc/eqn/neqn.sh
index 8a094d437..f72a1b46b 100644
--- a/src/preproc/eqn/neqn.sh
+++ b/src/preproc/eqn/neqn.sh
@@ -1,26 +1,67 @@
 #!/bin/sh
+#
 # Copyright (C) 2014-2024 Free Software Foundation, Inc.
 #
 # This file is part of groff.
-# 
+#
 # groff 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 2 of the License (GPL2).
-# 
-# groff is distributed in the hope that it will be useful, but WITHOUT ANY
-# WARRANTY; without even the implied warranty of MERCHANTABILITY or
+#
+# groff 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.
-# 
+#
 # The GPL2 license text is available in the internet at
 # <http://www.gnu.org/licenses/gpl-2.0.txt>.
 
-# Provision of this shell script should not be taken to imply that use of
-# GNU eqn with groff -Tascii|-Tlatin1|-Tutf8 is supported.
+# Provision of this shell script should not be taken to imply that use
+# of GNU eqn with groff -Tascii|-Tlatin1|-Tutf8 is supported.
+
+# Screen for shells non-conforming with POSIX Issue 4 (1994).
+badshell=yes
+# Solaris 10 /bin/sh is so wretched that it not only doesn't support
+# standard parameter expansion, but it also writes diagnostic messages
+# to the standard output instead of standard error.
+if [ -n "$SHELL" ]
+then
+  "$SHELL" -c 'prog=${0##*/}' >/dev/null 2>&1 && badshell=
+fi
+
+if [ -n "$badshell" ]
+then
+  prog=`basename $0`
+else
+  prog=${0##*/}
+fi
 
 @GROFF_BIN_PATH_SETUP@
 PATH="$GROFF_RUNTIME$PATH"
 export PATH
-exec @g@eqn -Tascii ${1+"$@"}
 
-# eof
+for arg
+do
+  case "$arg" in
+    -h|--help)
+      cat <<EOF
+usage: $prog [eqn-option ...] [file ...]
+usage: $prog {-h | --help}
+
+$prog invokes eqn(1) with the '-T ascii' option and any other arguments
+specified.  See the neqn(1) manual page.
+EOF
+      exit 0
+      ;;
+  esac
+done
+
+# Note: The construction '${1+"@$"}' preserves the absence of arguments
+# in old shells; see "Shell Substitutions" in the GNU Autoconf manual.
+# We don't want 'neqn' to become 'neqn ... ""' if $# equals zero.
+exec @g@eqn -T ascii ${1+"$@"}
+
+# Local Variables:
+# fill-column: 72
+# End:
+# vim: set autoindent expandtab shiftwidth=2 softtabstop=2 textwidth=72: