zsh: zstyle examples

zstyle_examples.zsh

# reference: http://zsh.sourceforge.net/Doc/Release/Zsh-Modules.html#The-zsh_002fzutil-Module
# https://unix.stackexchange.com/questions/214657/what-does-zstyle-do

# list all zstyle settings
zstyle -L

# set a string value
zstyle :example:favorites fruit apple

# set an explicit string value
zstyle -s ':example:favorites' 'computer' 'apple'

# assign new $fav variable with -g
zstyle -g fav ':example:favorites' fruit && echo $fav

# be explicit about the assignment data type:
# -a: array, -b: boolean, -s: string
zstyle -b ':example:favorites:vegtable' 'broccoli' no

# test with -t
if zstyle -t ':example:favorites' 'fruit' 'apple'; then
  echo "an apple a day keeps the dr. away"
fi
if ! zstyle -t ':example:favorites:vegtable' 'broccoli' 'no'; then
  echo "Broccoli is the deadliest plant on Earth - why, it tries to warn you itself with its terrible taste"
fi

# delete a value with -d
zstyle -d ':example:favorites' 'computer'

# list only zstyle settings for a certain pattern
zstyle -L ':example:favorites*'