Shell

シェルプログラミングはどこかに落とし穴がありそうで怖い．

依存性を持つ関数呼び出し

• dep.sh

  #!/bin/sh
  
  function die ()
  {
    local stat=$1
    local msg=$2
  
    echo "${msg}: ${stat}" 1>&2
    exit ${stat}
  }
  
  function _depnum ()
  {
    local tgt=$1
  
    for ((i=${#CHAIN[@]}; i >= 0; i--)); do
      if [ "x${tgt}" = "x${CHAIN[$i]}" ]; then
        echo $i
        exit 0
      fi
    done
  
    die 15 "ERR: no such target: ${tgt}"
  }
  
  function run ()
  {
    if [ -z "$CHAIN" ]; then
      die 33 "\`\$CHAIN' not declared"
    fi
  
    local tgt=$1
    local arg=$2
    local dnum=`_depnum ${tgt}`
  
    for ((i=0; i <= ${dnum}; i++)); do
      arg="`${CHAIN[$i]} ${arg}`"
    done
  
    if [ -n "${arg}" ]; then
      echo ${arg}
    fi
  }
  

• dop.sh

  #!/bin/sh
  
  source dep.sh
  
  function clean ()
  {
    echo "arg_clean:  $1" 1>&2
    echo "cleaned"
  }
  
  function pack ()
  {
    echo "arg_pack:   $1" 1>&2
    echo "packed"
  }
  
  function upload () 
  {
    echo "arg_upload: $1" 1>&2
    echo "uploaded"
  }
  
  CHAIN=(clean pack upload)
  
  if [ $# -eq 1 ]; then
    res=`run $1 init`
    echo
    echo "result: ${res}"
  else
    die 24 "syntax error"
  fi
  

• 実行結果

  $ sh dop.sh upload
  arg_clean:  init
  arg_pack:   cleaned
  arg_upload: packed
  
  result: uploaded
  
  $ sh dop.sh pack
  arg_clean:  init
  arg_pack:   cleaned
  
  result: packed
  
  $ sh dop.sh clean
  arg_clean:  init
  
  result: cleaned