# lexically bind environment variables to a block.
# create a new function _name_ with each argument _var_
# bound to its current value.

fn vbindfn {
	_args:=$*
	and {~ $#_args 0 1} {echo 'usage: vbindfn name block [var ...]' >[1=2]; raise usage}
	_let := ''
	for _ in ${tl ${tl $_args}} {
		echo doing $_
		_let=$_let^${quote $_}^':='^${quote $$_}^';'
	}
	fn ${hd $_args} ${parse '{'^$_let^${hd ${tl $_args}}^' $*}'}
}