Word Language

  [Joining]       osh-word-join 'single'\'$myvar"double $x"
  [Quotes]        osh-string    'abc'  $'line\n'  "$var"
  [Substitutions] command-sub   $(date)   `date`
                  var-sub       ${var}   $0   $9   
                  arith-sub     $((1 + 2))
                  tilde-sub     ~/src
                  proc-sub      diff <(sort L.txt) <(sort R.txt)
  [Var Ops]       op-bracket    ${a[i+1]}, ${a[*]}
                  op-indirect   ${!x}
                  op-test       ${x:-default}
                  op-strip      ${x%%suffix}  etc.
                  op-patsub     ${x//y/z}
                  op-slice      ${a[@]:0:1}
                  op-format     ${x@P} ${x@Q} etc.
