parseargs.es

#!/usr/bin/env es

fn es_canonicalize_args args {
	let (res=;tmp=) {
		for (i = $args) {
			if {~ $i '-'^*} {
				tmp = <={~~ $i '-'^*}
				if {eq <={%count $:tmp} 0} {
					res = $res '-'
				} {gt <={%count $:tmp} 1} {
					res = $res '-'^<={%strlist $tmp}
				} {
					res = $res $i
				}
			} {
				if {! ~ <={%count $:i} 0} {
					res = $res $i
				}
			}
		}
		result $res
	}
}

let (
	fn es_run_parseargs argfn usagefn args {
		local (
			i = 1
			argslen = $#args
			cur =
			next =
			advance = 1
			flagarg = ''
			get-flagarg = @{
				if {~ $next '-'^*} {
					throw parseargs_error
				} {~ $#next 0 } {
					throw parseargs_error
				} {
					advance = 2
					result $next
				}
			}
			fn-usage = @{ throw parseargs_error }
			fn-done = @{ throw parseargs_done }
			fn-has_argument = @{ if {! ~ $next '-'^* && ! ~ $#next 0} { true } { false } }
		) {
			catch @ e t m {
				if {~ $e parseargs_error} {
					$usagefn
					result <=false
				} {~ $e parseargs_done} {
					result <=true $args
				} {
					throw $e $t $m
				}
			} {
				while {lte $i $argslen} {
					advance = 1
					cur = $args(1)
					if {! ~ $cur '-'^*} { throw parseargs_done }
					next = $args(2)
					$argfn $cur
					i = <={add $i $advance}
					args = $args(<={add 1 $advance} ...)
				}
				result <=true $args
			}
		}
	}
) {
	fn parseargs argfn maybe-usagefn maybe-args {
		if {~ $maybe-usagefn '@'^* || ~ $maybe-usagefn '%closure'^*} {
			es_run_parseargs $argfn $maybe-usagefn <={es_canonicalize_args $maybe-args}
		} {
			es_run_parseargs $argfn \
				@{throw error usage 'invalid arguments'} \
				<={es_canonicalize_args $maybe-usagefn $maybe-args}
		}
	}
}