Bash – assign and inspect bash function metadata

bashfunction

I often generate and register a lot of bash functions that automate many of the task I usually do in my development projects. That generation depends on the meta-data of the project I am working on.

I want to annotate the functions with the info of the project they were generated, this way:

func1() {
# This function was generated for project: PROJECT1
echo "do my automation"
}

Ideally, I would be able to see the comment when I inspect the definition:

$ type func1

func1 is a function
func1 () 
{
    # This function was generated for project: PROJECT1
    echo "do my automation"
}

But somehow bash seems to ignore the comments at the moment of loading the function, not when executing it. So the comments are lost and I get this result:

func1 is a function
func1 () 
{
    echo "do my automation"
}

Is there any way to assign metadata to functions, and check them afterwards? It is possible to retrieve it when inspecting the definition with type?

Best Answer

function func_name()
{
  : '
  Invocation:   func_name $1 $2 ... $n
  Function:     Display the values of the supplied arguments, in double quotes.
  Exit status:  func_name always returns with exit status 0.
  ' :
  local i
  echo "func_name: $# arguments"
  for ((i = 1; i <= $#; ++i)); do
    echo "func_name [$i] \"$1\""
    shift
  done
  return 0
}

Related Solutions

Bash Function Decorator

That would be a lot easier with zsh that has anonymous functions and a special associative array with function codes. With bash however you could do something like:

decorate() {
  eval "
    _inner_$(typeset -f "$1")
    $1"'() {
      echo >&2 "Calling function '"$1"' with $# arguments"
      _inner_'"$1"' "$@"
      local ret=$?
      echo >&2 "Function '"$1"' returned with exit status $ret"
      return "$ret"
    }'
}

f() {
  echo test
  return 12
}
decorate f
f a b

Which would output:

Calling function f with 2 arguments
test
Function f returned with exit status 12

You can't call decorate twice to decorate your function twice though.

With zsh:

decorate()
  functions[$1]='
    echo >&2 "Calling function '$1' with $# arguments"
    () { '$functions[$1]'; } "$@"
    local ret=$?
    echo >&2 "function '$1' returned with status $ret"
    return $ret'

Bash – Calling `source` from bash function

You can change your mySource function to:

mySource() {
  source "$1"
}

Then calling it with:

$ mySource file.sh
$ printf '%s\n' "$FILE"
success

You can also make mySource handles multiple files:

mySource() {
  for f do
    source "$f"
  done
}

Best Answer

Related Solutions

Bash Function Decorator

Bash – Calling `source` from bash function

Related Question