Demonstration of docopt.sh

naval_fate.sh

#!/usr/bin/env bash

DOC="Naval Fate.

Usage:
  naval_fate.sh ship <name> move <x> <y> [--speed=<kn>]
  naval_fate.sh ship shoot <x> <y>

Options:
  --speed=<kn>  Speed in knots [default: 10].
  --moored      Moored (anchored) mine.
  --drifting    Drifting mine."
naval_fate() {
  eval "$(docopt "$@")"
  $ship && $move && printf "The %s is now moving to %d,%d at %d knots.\n" "$_name_" "$_x_" "$_y_" "$__speed"
  $ship && $shoot && printf "You shoot at %d,%d. It's a hit!\n" "$_x_" "$_y_"
  return 0
}
naval_fate "$@"

naval_fate_patched.sh

#!/usr/bin/env bash

DOC="Naval Fate.

Usage:
  naval_fate.sh ship <name> move <x> <y> [--speed=<kn>]
  naval_fate.sh ship shoot <x> <y>

Options:
  --speed=<kn>  Speed in knots [default: 10].
  --moored      Moored (anchored) mine.
  --drifting    Drifting mine."
# docopt parser below, refresh this parser with `docopt.sh naval_fate.sh`
# shellcheck disable=2016,2154,1075
docopt() { parse() { if ${DOCOPT_DOC_CHECK:-true}; then local doc_hash
doc_hash=$(printf "%s" "$DOC" | shasum -a 256)
if [[ ${doc_hash:0:5} != "$digest" ]]; then
stderr "The current usage doc (${doc_hash:0:5}) does not match \
what the parser was generated with (${digest})
Run \`docopt.sh\` to refresh the parser."; _return 70; fi; fi; local root_idx=$1
shift; argv=("$@"); parsed_params=(); parsed_values=(); left=(); testdepth=0
local arg; while [[ ${#argv[@]} -gt 0 ]]; do if [[ ${argv[0]} = "--" ]]; then
for arg in "${argv[@]}"; do parsed_params+=('a'); parsed_values+=("$arg"); done
break; elif [[ ${argv[0]} = --* ]]; then parse_long
elif [[ ${argv[0]} = -* && ${argv[0]} != "-" ]]; then parse_shorts
elif ${DOCOPT_OPTIONS_FIRST:-false}; then for arg in "${argv[@]}"; do
parsed_params+=('a'); parsed_values+=("$arg"); done; break; else
parsed_params+=('a'); parsed_values+=("${argv[0]}"); argv=("${argv[@]:1}"); fi
done; local idx; if ${DOCOPT_ADD_HELP:-true}; then
for idx in "${parsed_params[@]}"; do [[ $idx = 'a' ]] && continue
if [[ ${shorts[$idx]} = "-h" || ${longs[$idx]} = "--help" ]]; then
stdout "$trimmed_doc"; _return 0; fi; done; fi
if [[ ${DOCOPT_PROGRAM_VERSION:-false} != 'false' ]]; then
for idx in "${parsed_params[@]}"; do [[ $idx = 'a' ]] && continue
if [[ ${longs[$idx]} = "--version" ]]; then stdout "$DOCOPT_PROGRAM_VERSION"
_return 0; fi; done; fi; local i=0; while [[ $i -lt ${#parsed_params[@]} ]]; do
left+=("$i"); ((i++)) || true; done
if ! required "$root_idx" || [ ${#left[@]} -gt 0 ]; then error; fi; return 0; }
parse_shorts() { local token=${argv[0]}; local value; argv=("${argv[@]:1}")
[[ $token = -* && $token != --* ]] || _return 88; local remaining=${token#-}
while [[ -n $remaining ]]; do local short="-${remaining:0:1}"
remaining="${remaining:1}"; local i=0; local similar=(); local match=false
for o in "${shorts[@]}"; do if [[ $o = "$short" ]]; then similar+=("$short")
[[ $match = false ]] && match=$i; fi; ((i++)) || true; done
if [[ ${#similar[@]} -gt 1 ]]; then
error "${short} is specified ambiguously ${#similar[@]} times"
elif [[ ${#similar[@]} -lt 1 ]]; then match=${#shorts[@]}; value=true
shorts+=("$short"); longs+=(''); argcounts+=(0); else value=false
if [[ ${argcounts[$match]} -ne 0 ]]; then if [[ $remaining = '' ]]; then
if [[ ${#argv[@]} -eq 0 || ${argv[0]} = '--' ]]; then
error "${short} requires argument"; fi; value=${argv[0]}; argv=("${argv[@]:1}")
else value=$remaining; remaining=''; fi; fi; if [[ $value = false ]]; then
value=true; fi; fi; parsed_params+=("$match"); parsed_values+=("$value"); done
}; parse_long() { local token=${argv[0]}; local long=${token%%=*}
local value=${token#*=}; local argcount; argv=("${argv[@]:1}")
[[ $token = --* ]] || _return 88; if [[ $token = *=* ]]; then eq='='; else eq=''
value=false; fi; local i=0; local similar=(); local match=false
for o in "${longs[@]}"; do if [[ $o = "$long" ]]; then similar+=("$long")
[[ $match = false ]] && match=$i; fi; ((i++)) || true; done
if [[ $match = false ]]; then i=0; for o in "${longs[@]}"; do
if [[ $o = $long* ]]; then similar+=("$long"); [[ $match = false ]] && match=$i
fi; ((i++)) || true; done; fi; if [[ ${#similar[@]} -gt 1 ]]; then
error "${long} is not a unique prefix: ${similar[*]}?"
elif [[ ${#similar[@]} -lt 1 ]]; then
[[ $eq = '=' ]] && argcount=1 || argcount=0; match=${#shorts[@]}
[[ $argcount -eq 0 ]] && value=true; shorts+=(''); longs+=("$long")
argcounts+=("$argcount"); else if [[ ${argcounts[$match]} -eq 0 ]]; then
if [[ $value != false ]]; then
error "${longs[$match]} must not have an argument"; fi
elif [[ $value = false ]]; then
if [[ ${#argv[@]} -eq 0 || ${argv[0]} = '--' ]]; then
error "${long} requires argument"; fi; value=${argv[0]}; argv=("${argv[@]:1}")
fi; if [[ $value = false ]]; then value=true; fi; fi; parsed_params+=("$match")
parsed_values+=("$value"); }; required() { local initial_left=("${left[@]}")
local node_idx; ((testdepth++)) || true; for node_idx in "$@"; do
if ! "node_$node_idx"; then left=("${initial_left[@]}"); ((testdepth--)) || true
return 1; fi; done; if [[ $((--testdepth)) -eq 0 ]]; then
left=("${initial_left[@]}"); for node_idx in "$@"; do "node_$node_idx"; done; fi
return 0; }; either() { local initial_left=("${left[@]}"); local best_match_idx
local match_count; local node_idx; ((testdepth++)) || true
for node_idx in "$@"; do if "node_$node_idx"; then
if [[ -z $match_count || ${#left[@]} -lt $match_count ]]; then
best_match_idx=$node_idx; match_count=${#left[@]}; fi; fi
left=("${initial_left[@]}"); done; ((testdepth--)) || true
if [[ -n $best_match_idx ]]; then "node_$best_match_idx"; return 0; fi
left=("${initial_left[@]}"); return 1; }; optional() { local node_idx
for node_idx in "$@"; do "node_$node_idx"; done; return 0; }; _command() {
local i; local name=${2:-$1}; for i in "${!left[@]}"; do local l=${left[$i]}
if [[ ${parsed_params[$l]} = 'a' ]]; then
if [[ ${parsed_values[$l]} != "$name" ]]; then return 1; fi
left=("${left[@]:0:$i}" "${left[@]:((i+1))}")
[[ $testdepth -gt 0 ]] && return 0; if [[ $3 = true ]]; then
eval "((var_$1++)) || true"; else eval "var_$1=true"; fi; return 0; fi; done
return 1; }; value() { local i; for i in "${!left[@]}"; do local l=${left[$i]}
if [[ ${parsed_params[$l]} = "$2" ]]; then
left=("${left[@]:0:$i}" "${left[@]:((i+1))}")
[[ $testdepth -gt 0 ]] && return 0; local value
value=$(printf -- "%q" "${parsed_values[$l]}"); if [[ $3 = true ]]; then
eval "var_$1+=($value)"; else eval "var_$1=$value"; fi; return 0; fi; done
return 1; }; stdout() { printf -- "cat <<'EOM'\n%s\nEOM\n" "$1"; }; stderr() {
printf -- "cat <<'EOM' >&2\n%s\nEOM\n" "$1"; }; error() {
[[ -n $1 ]] && stderr "$1"; stderr "$usage"; _return 1; }; _return() {
printf -- "exit %d\n" "$1"; exit "$1"; }; set -e; trimmed_doc=${DOC:0:237}
usage=${DOC:13:97}; digest=6780a; shorts=(''); longs=(--speed); argcounts=(1)
node_0(){ value __speed 0; }; node_1(){ value _name_ a; }; node_2(){ value _x_ a
}; node_3(){ value _y_ a; }; node_4(){ _command ship; }; node_5(){ _command move
}; node_6(){ _command shoot; }; node_13(){ optional 0; }; node_14(){
required 4 1 5 2 3 13; }; node_19(){ required 4 6 2 3; }; node_20(){
either 14 19; }; node_21(){ required 20; }; cat <<<' docopt_exit() {
[[ -n $1 ]] && printf "%s\n" "$1" >&2; printf "%s\n" "${DOC:13:97}" >&2; exit 1
}'; unset var___speed var__name_ var__x_ var__y_ var_ship var_move var_shoot
parse 21 "$@"; local prefix=${DOCOPT_PREFIX:-''}; local docopt_decl=1
[[ $BASH_VERSION =~ ^4.3 ]] && docopt_decl=2; unset "${prefix}__speed" \
"${prefix}_name_" "${prefix}_x_" "${prefix}_y_" "${prefix}ship" \
"${prefix}move" "${prefix}shoot"; eval "${prefix}"'__speed=${var___speed:-10}'
eval "${prefix}"'_name_=${var__name_:-}'; eval "${prefix}"'_x_=${var__x_:-}'
eval "${prefix}"'_y_=${var__y_:-}'; eval "${prefix}"'ship=${var_ship:-false}'
eval "${prefix}"'move=${var_move:-false}'
eval "${prefix}"'shoot=${var_shoot:-false}'; local docopt_i=0
for ((docopt_i=0;docopt_i<docopt_decl;docopt_i++)); do
declare -p "${prefix}__speed" "${prefix}_name_" "${prefix}_x_" "${prefix}_y_" \
"${prefix}ship" "${prefix}move" "${prefix}shoot"; done; }
# docopt parser above, complete command for generating this parser is `docopt.sh naval_fate.sh`
naval_fate() {
  eval "$(docopt "$@")"
  $ship && $move && printf "The %s is now moving to %d,%d at %d knots.\n" "$_name_" "$_x_" "$_y_" "$__speed"
  $ship && $shoot && printf "You shoot at %d,%d. It's a hit!\n" "$_x_" "$_y_"
  return 0
}
naval_fate "$@"