Rebol Programming/do-boot

= USAGE: = DO-BOOT target args dependent

= DESCRIPTION: = Does a value only if it and its file (URL) and it's dependent exists.

DO-BOOT is a function value. = ARGUMENTS =
 * target -- (Type: any)
 * args -- (Type: any)
 * dependent -- (Type: any)

= SOURCE CODE = do-boot: func [ {Does a value only if it and its file (URL) and it's dependent exists.} target args dependent /local check dir ][   check: func [target /local tmp] [ if exists? target [return make file! 1]        if exists? system/options/home/:target [return system/options/home] none ]    if target [ if dependent [dir: check dependent] if none? dir [dir: check target] if dir [ dir: append copy dir target if exists? dir [do/args dir args return true] ]   ]     false ]