shithub: mc

ref: 3b80bdf127a0e3d1551a4393008f702ca022f2b3
dir: /libstd/optparse.myr/

use "alloc.use"
use "die.use"
use "extremum.use"
use "fmt.use"
use "slappend.use"
use "sys.use"
use "types.use"
use "utf.use"

pkg std =
	type optctx = struct
		/* data passed in */
		opts	: byte[:]
		args	: byte[:][:]

		/* state */
		optdone	: bool	/* if we've seen '--', everything's an arg */
		done	: bool	/* if we've processed all the args */
		argidx	: size
		curarg	: byte[:]
		arglist	: byte[:][:]
	;;

	const optinit	: (opts	: byte[:], args : byte[:][:] -> optctx#)
	const optnext	: (ctx : optctx# -> [char, byte[:]])
	const optdone	: (ctx : optctx# -> bool)
;;

const optinit = {opts, args
	var ctx

	ctx = alloc()
	ctx.opts = opts
	ctx.args = args

	ctx.optdone = false
	ctx.done = false
	ctx.argidx = 0
	ctx.arglist = [][:]
	ctx.curarg = [][:]
	next(ctx)
	-> ctx
}

const optnext = {ctx
	var c
	var arg
	var valid
	var tryarg
	var needarg

	(c, ctx.curarg) = striter(ctx.curarg)

	(valid, tryarg, needarg) = optinfo(ctx, c)
	if !valid
		put("Unexpected argument %c\n", c)
		exit(1)
	elif tryarg && ctx.curarg.len > 0
		arg = ctx.curarg
		ctx.curarg = ctx.curarg[ctx.curarg.len:]
	elif tryarg && ctx.argidx < (ctx.args.len - 1)
		arg = ctx.args[ctx.argidx + 1]
		ctx.argidx++
		next(ctx)
	elif needarg
		put("Expected argument for %c\n", c)
		exit(1)
	else
		arg = ""
	;;

	if !ctx.curarg.len
		next(ctx)
	;;

	-> (c, arg)
}

const optdone = {ctx
	-> !ctx.curarg.len && ctx.done
}

const optinfo = {ctx, arg
	var s
	var c

	s = ctx.opts
	while s.len != 0
		(c, s) = striter(s)
		if c == arg
			(c, s) = striter(s)
			/* mandatory arg */
			if c == ':'
				-> (true, true, true)
			/* optional arg */
			elif c == '?'
				-> (true, true, false)
			/* no arg */
			else
				-> (true, false, false)
			;;
		;;
	;;
	-> (false, false)
}

const next = {ctx
	var i

	for i = ctx.argidx + 1; i < ctx.args.len; i++
		if !ctx.optdone && decode(ctx.args[i]) == '-'
			goto foundopt
		else
			ctx.arglist = slappend(ctx.arglist, ctx.args[i])
		;;
	;;
	ctx.done = true
	-> false
:foundopt
	ctx.argidx = i
	ctx.curarg = ctx.args[i][1:]
	-> true
}