Re: PATCH: minor variable allocation change in add-zsh-hook

[Mikael Magnusson <mikachu@xxxxxxxxx>]

On Fri, Oct 2, 2015 at 11:06 PM, Matthew Hamilton <M@xxxxxxxxxxxxxx> wrote:
> The 'local usage' variable is allocated in main, outside of the if loop
> that determines if it is going to print the usage information. This
> means time is spent allocating that variable, when in most cases, it
> will never be printed. It would be better to set it within the if loop,
> or alternatively, not using a variable and simply output the usage text
> as as literal string (as many other functions do).
>
> A trace of the time being needlessly being spent allocating the variable
> can be seen here: https://gist.github.com/Eriner/3192c9eb98fabdd70607
>
> It's not that much time, but it adds up and is inefficient/unnecessary.
>
> diff --git a/Functions/Misc/add-zsh-hook b/Functions/Misc/add-zsh-hook
> index ee37d67..bccd115 100644
> --- a/Functions/Misc/add-zsh-hook
> +++ b/Functions/Misc/add-zsh-hook
> @@ -19,7 +19,6 @@ hooktypes=(
>    chpwd precmd preexec periodic zshaddhistory zshexit
>    zsh_directory_name
>  )
> -local usage="Usage: $0 hook function\nValid hooks are:\n  $hooktypes"
>
>  local opt
>  local -a autoopts
> @@ -58,6 +57,7 @@ if (( list )); then
>    typeset -mp "(${1:-${(@j:|:)hooktypes}})_functions"
>    return $?
>  elif (( help || $# != 2 || ${hooktypes[(I)$1]} == 0 )); then
> +  local usage="Usage: $0 hook function\nValid hooks are:\n  $hooktypes"
>    print -u$(( 2 - help )) $usage
>    return $(( 1 - help ))
>  fi

You would need to add tens of thousands of hooks before this would
make any difference, and then you're already far past the point of
sanity. I like the way the current code separates the content and
logic. There is also no such thing as an "if loop".

-- 
Mikael Magnusson