subcommand: Use pager for man output if possible.
[gsu.git] / subcommand
index 1e04d16c8f047b59105e5bf614070295f73fb0da..ab6ae8a239b36609d6f6dbe1ce4b24e1e31087d1 100644 (file)
@@ -1,5 +1,6 @@
 #!/bin/bash
-# (C) 2006-2011 Andre Noll
+# Copyright (C) 2006 Andre Noll
+# Licensed under the LGPL, version 3. See COPYING and COPYING.LESSER.
 
 if [[ "$(type -t _gsu_setup)" != "function" ]]; then
        gsu_dir=${gsu_dir:-${BASH_SOURCE[0]%/*}}
@@ -24,7 +25,7 @@ _gsu_usage()
 # exactly one parenthesized subexpression for matching the command name.
 _gsu_get_command_regex()
 {
-       local cmd="${1:-[-a-zA-Z_0-9]+}"
+       local cmd="${1:-[-a-zA-Z_0-9]{1,\}}"
        result="^com_($cmd)\(\)"
 }
 
@@ -49,15 +50,131 @@ _gsu_available_commands()
        } | sort | tr '\n' ' ')"
 }
 
+# Check number of arguments.
+#
+# Usage: gsu_check_arg_count <num_given> <num1> [<num2>]
+#
+# Check that <num_given> is between <num1> and <num2> inclusively.
+# If only <num1> ist given, num2 is assumed to be infinity.
+#
+# Examples:
+#      0 0 no argument allowed
+#      1 1 exactly one argument required
+#      0 2 at most two arguments admissible
+#      2   at least two arguments required
+gsu_check_arg_count()
+{
+       ret=-$E_GSU_BAD_ARG_COUNT
+       if (($# == 2)); then # only num1 is given
+               result="at least $2 args required, $1 given"
+               (($1 < $2)) && return
+               ret=$GSU_SUCCESS
+               return
+       fi
+       # num1 and num2 given
+       result="need at least $2 args, $1 given"
+       (($1 < $2)) && return
+       result="need at most $3 args, $1 given"
+       (($1 > $3)) && return
+       ret=$GSU_SUCCESS
+}
+
+# Wrapper for the bash getopts builtin.
+#
+# Aborts on programming errors such as missing or invalid option string.  On
+# success $result contains shell code that can be eval'ed. For each defined
+# option x, the local variable o_x will be created when calling eval "$result".
+# o_x contains true/false for options without argument and either the empty
+# string or the given argument for options that take an argument.
+#
+# Example:
+#      gsu_getopts abc:x:y
+#      eval "$result"
+#      (($ret < 0)) && return
+#
+#      [[ "$o_a" = 'true' ]] && echo 'The -a flag was given'
+#      [[ -n "$o_c" ]] && echo "The -c option was given with arg $o_c"
+gsu_getopts()
+{
+       local i c tab=' ' cr='
+'
+
+       gsu_check_arg_count $# 1 1
+       if (($ret < 0)); then
+               gsu_err_msg
+               exit 1
+       fi
+
+       ret=-$E_GSU_GETOPTS
+       result="invalid optstring $1"
+       if [[ -z "$1" ]] || grep -q '::' <<< "$1" ; then
+               gsu_err_msg
+               exit 1
+       fi
+
+       for ((i=0; i < ${#1}; i++)); do
+               c=${1:$i:1}
+               case "$c" in
+               [a-zA-Z:]);;
+               *)
+                       ret=-$E_GSU_GETOPTS
+                       result="invalid character $c in optstring"
+                       gsu_err_msg
+                       exit 1
+               esac
+       done
+       result="local _gsu_getopts_opt"
+       for ((i=0; i < ${#1}; i++)); do
+               c1=${1:$i:1}
+               c2=${1:$(($i + 1)):1}
+               result+=" o_$c1="
+               if [[ "$c2" = ":" ]]; then
+                       let i++
+               else
+                       result+="false"
+               fi
+       done
+       result+="
+       OPTIND=1
+       while getopts $1 _gsu_getopts_opt \"\$@\"; do
+               case \"\$_gsu_getopts_opt\" in
+"
+       for ((i=0; i < ${#1}; i++)); do
+               c1=${1:$i:1}
+               c2=${1:$(($i + 1)):1}
+               result+="$tab$tab$c1) o_$c1="
+               if [[ "$c2" = ":" ]]; then
+                       result+="\"\$OPTARG\""
+                       let i++
+               else
+                       result+="true"
+               fi
+               result+=";;$cr"
+       done
+       result+="
+               *)
+                       ret=-\$E_GSU_GETOPTS
+                       result=\"invalid option given\"
+                       return
+                       ;;
+               esac
+       done
+       shift \$((\$OPTIND - 1))
+"
+       ret=$GSU_SUCCESS
+}
+
 _gsu_print_available_commands()
 {
-       local cmd
+       local cmd cmds
        local -i count=0
 
+       _gsu_available_commands
+       cmds="$result"
        printf 'Available commands:\n'
-       for cmd in $gsu_cmds; do
+       for cmd in $cmds; do
                printf '%s' "$cmd"
-               let count++
+               let ++count
                if (($count % 4)); then
                        printf '\t'
                        ((${#cmd} < 8)) && printf '\t'
@@ -90,19 +207,23 @@ gsu_complete_options()
        done
 }
 
-export gsu_prefs_txt="
+com_prefs_options='e'
+
+_gsu_prefs_txt="
 Print the current preferences.
 
 Usage: prefs [-e]
 
-If -e is given, the config file is opened with the default editor.  Without
-options, the command prints out a list of all cmt config variables, together
-with their current value and the default value."
-_com_prefs()
+If -e is given, the config file is opened with the default editor.
+Without options, the command prints out a list of all config variables,
+together with their current value and the default value.
+"
+
+com_prefs()
 {
        local i conf="${gsu_config_file:=${HOME:-}/.$gsu_name.rc}"
 
-       gsu_getopts "e"
+       gsu_getopts "$com_prefs_options"
        eval "$result"
        (($ret < 0)) && return
        gsu_check_arg_count $# 0 0
@@ -146,29 +267,42 @@ _com_prefs()
        done
 }
 
+_gsu_isatty()
+{(
+       exec 3<&1
+       stty 0<&3 &> /dev/null
+)}
+
 complete_prefs()
 {
-       gsu_complete_options "e" "$@"
+       gsu_complete_options "$com_prefs_options" "$@"
 }
 
-export gsu_man_txt="
+_gsu_man_txt='
 Print the manual.
 
-Usage: man"
+Usage: man
 
-_com_man()
+If stdout associated with a terminal device, output is piped to
+$PAGER. If $PAGER is unset, less(1) is assumed.
+'
+
+com_man()
 {
        local equal_signs="=================================================="
        local minus_signs="--------------------------------------------------"
-        local com num
+       local com num pager='cat'
 
+       _gsu_isatty && pager="${PAGER:-less}"
+       [[ "$pager" == 'less' ]] && export LESS=${LESS-RI}
+       {
        echo "$gsu_name (_${gsu_banner_txt}_) manual"
        echo "${equal_signs:0:${#gsu_name} + ${#gsu_banner_txt} + 16}"
        echo
 
-        sed -e '1,/^#\{70,\}/d' -e '/^#\{70,\}/,$d' $0 -e 's/^# *//'
+       sed -e '1,/^#\{70,\}/d' -e '/^#\{70,\}/,$d' $0 -e 's/^# *//'
        echo "----"
-        echo
+       echo
        echo "$gsu_name usage"
        echo "${minus_signs:0:${#gsu_name} + 6}"
        printf "\t"
@@ -180,19 +314,20 @@ _com_man()
        echo "Available commands:"
 
        _gsu_available_commands
-        for com in $result; do
+       for com in $result; do
                num=${#com}
                (($num < 4)) && num=4
-                echo "${minus_signs:0:$num}"
-                echo "$com"
-                echo "${minus_signs:0:$num}"
-                $0 help $com
+               echo "${minus_signs:0:$num}"
+               echo "$com"
+               echo "${minus_signs:0:$num}"
+               $0 help $com
                echo
-        done
-        ret=$GSU_SUCCESS
+       done
+       } | $pager
+       ret=$GSU_SUCCESS
 }
 
-export gsu_help_txt="
+_gsu_help_txt="
 Print online help.
 
 Usage: help [command]
@@ -200,7 +335,7 @@ Usage: help [command]
 Without arguments, print the list of available commands. Otherwise,
 print the help text for the given command."
 
-export gsu_complete_txt="
+_gsu_complete_txt="
 Command line completion.
 
 Usage: complete [<cword> <word>...]
@@ -214,7 +349,7 @@ written to stdout. This can be used from the completion function of
 the subcommand.
 "
 
-_com_help()
+com_help()
 {
        local a b ere tab='     '
 
@@ -225,10 +360,10 @@ _com_help()
                gsu_short_msg "### $gsu_name -- $gsu_banner_txt ###"
                _gsu_usage 2>&1
                {
-                       printf "com_help()\n$gsu_help_txt" | head -n 4; echo "--"
-                       printf "com_man()\n$gsu_man_txt" | head -n 4; echo "--"
-                       printf "com_prefs()\n$gsu_prefs_txt" | head -n 4; echo "--"
-                       printf "com_complete()\n$gsu_complete_txt" | head -n 4; echo "--"
+                       printf "com_help()\n$_gsu_help_txt" | head -n 4; echo "--"
+                       printf "com_man()\n$_gsu_man_txt" | head -n 4; echo "--"
+                       printf "com_prefs()\n$_gsu_prefs_txt" | head -n 4; echo "--"
+                       printf "com_complete()\n$_gsu_complete_txt" | head -n 4; echo "--"
                        grep -EA 2 "$ere" $0
                } | grep -v -- '--' \
                        | sed -En "/$ere/"'!d
@@ -257,22 +392,22 @@ _com_help()
                return
        fi
        if test "$1" = "help"; then
-               echo "$gsu_help_txt"
+               echo "$_gsu_help_txt"
                ret=$GSU_SUCCESS
                return
        fi
        if test "$1" = "man"; then
-               echo "$gsu_man_txt"
+               echo "$_gsu_man_txt"
                ret=$GSU_SUCCESS
                return
        fi
        if test "$1" = "prefs"; then
-               echo "$gsu_prefs_txt"
+               echo "$_gsu_prefs_txt"
                ret=$GSU_SUCCESS
                return
        fi
        if test "$1" = "complete"; then
-               echo "$gsu_complete_txt"
+               echo "$_gsu_complete_txt"
                ret=$GSU_SUCCESS
                return
        fi
@@ -311,92 +446,7 @@ complete_help()
        echo "$result"
 }
 
-# Wrapper for the bash getopts builtin.
-#
-# Aborts on programming errors such as missing or invalid option string.  On
-# success $result contains shell code that can be eval'ed. For each defined
-# option x, the local variable o_x will be created when calling eval "$result".
-# o_x contains true/false for options without argument and either the empty
-# string or the given argument for options that take an argument.
-#
-# Example:
-#      gsu_getopts abc:x:y
-#      eval "$result"
-#      (($ret < 0)) && return
-#
-#      [[ "$o_a" = 'true' ]] && echo 'The -a flag was given'
-#      [[ -n "$o_c" ]] && echo "The -c option was given with arg $o_c"
-gsu_getopts()
-{
-       local i c tab=' ' cr='
-'
-
-       gsu_check_arg_count $# 1 1
-       if (($ret < 0)); then
-               gsu_err_msg
-               exit 1
-       fi
-
-       ret=-$E_GSU_GETOPTS
-       result="invalid optstring $1"
-       if [[ -z "$1" ]] || grep -q '::' <<< "$1" ; then
-               gsu_err_msg
-               exit 1
-       fi
-
-       for ((i=0; i < ${#1}; i++)); do
-               c=${1:$i:1}
-               case "$c" in
-               [a-zA-Z:]);;
-               *)
-                       ret=-$E_GSU_GETOPTS
-                       result="invalid character $c in optstring"
-                       gsu_err_msg
-                       exit 1
-               esac
-       done
-       result="local _gsu_getopts_opt"
-       for ((i=0; i < ${#1}; i++)); do
-               c1=${1:$i:1}
-               c2=${1:$(($i + 1)):1}
-               result+=" o_$c1="
-               if [[ "$c2" = ":" ]]; then
-                       let i++
-               else
-                       result+="false"
-               fi
-       done
-       result+="
-       OPTIND=1
-       while getopts $1 _gsu_getopts_opt \"\$@\"; do
-               case \"\$_gsu_getopts_opt\" in
-"
-       for ((i=0; i < ${#1}; i++)); do
-               c1=${1:$i:1}
-               c2=${1:$(($i + 1)):1}
-               result+="$tab$tab$c1) o_$c1="
-               if [[ "$c2" = ":" ]]; then
-                       result+="\"\$OPTARG\""
-                       let i++
-               else
-                       result+="true"
-               fi
-               result+=";;$cr"
-       done
-       result+="
-               *)
-                       ret=-\$E_GSU_GETOPTS
-                       result=\"invalid option given\"
-                       return
-                       ;;
-               esac
-       done
-       shift \$((\$OPTIND - 1))
-"
-       ret=$GSU_SUCCESS
-}
-
-_com_complete()
+com_complete()
 {
        local cmd n cword
        local -a words
@@ -526,8 +576,7 @@ gsu_get_unnamed_arg_num()
 gsu()
 {
        local i
-       _gsu_available_commands
-       gsu_cmds="$result"
+
        if (($# == 0)); then
                _gsu_usage
                _gsu_print_available_commands
@@ -535,60 +584,17 @@ gsu()
        fi
        arg="$1"
        shift
-       # check internal commands
-       if [[ "$arg" = "help" || "$arg" = "man" || "$arg" = "prefs" || "$arg" = "complete" ]]; then
-               _com_$arg "$@"
+       if [[ "$(type -t com_$arg)" == 'function' ]]; then
+               com_$arg "$@"
                if (("$ret" < 0)); then
                        gsu_err_msg
                        exit 1
                fi
                exit 0
        fi
-
-       # external commands
-       for i in $gsu_cmds; do
-               if test "$arg" = "$i"; then
-                       com_$arg "$@"
-                       if (("$ret" < 0)); then
-                               gsu_err_msg
-                               exit 1
-                       fi
-                       exit 0
-               fi
-       done
-
        ret=-$E_GSU_BAD_COMMAND
        result="$arg"
        gsu_err_msg
        _gsu_print_available_commands
        exit 1
 }
-
-# Check number of arguments.
-#
-# Usage: gsu_check_arg_count <num_given> <num1> [<num2>]
-#
-# Check that <num_given> is between <num1> and <num2> inclusively.
-# If only <num1> ist given, num2 is assumed to be infinity.
-#
-# Examples:
-#      0 0 no argument allowed
-#      1 1 exactly one argument required
-#      0 2 at most two arguments admissible
-#      2   at least two arguments required
-gsu_check_arg_count()
-{
-       ret=-$E_GSU_BAD_ARG_COUNT
-       if (($# == 2)); then # only num1 is given
-               result="at least $2 args required, $1 given"
-               (($1 < $2)) && return
-               ret=$GSU_SUCCESS
-               return
-       fi
-       # num1 and num2 given
-       result="need at least $2 args, $1 given"
-       (($1 < $2)) && return
-       result="need at most $3 args, $1 given"
-       (($1 > $3)) && return
-       ret=$GSU_SUCCESS
-}