shithub: limbobyexample

ref: eac284d17b14eb4602387eb47c644fcf4f6e86c0
dir: /Generics/generics.b/

implement Generics;

include "sys.m";
include "draw.m";
include "bufio.m";

sys: Sys;
print: import sys;

bufio: Bufio;
Iobuf: import bufio;

Generics: module {
	init: fn(nil: ref Draw->Context, nil: list of string);
};

Rd: adt[T] {
	t:	ref Iobuf;
	ws:	fn(rd: self ref Rd[T]): int;
};

# Polymorphic type
Word: adt[T] {
	w: T;

	pick {
		String =>
			s: string;
	}

	eq:	fn(a, b: ref Word): int;
};

Integer: adt {
	d: int;
};

Int: type ref Integer;

init(nil: ref Draw->Context, nil: list of string) {
	sys = load Sys Sys->PATH;
	bufio = load Bufio Bufio->PATH;

	in := bufio->open("/fd/0", bufio->OREAD);

	rd := ref Rd[ref Iobuf](in);

	print("Type something: ");

	c := rd.ws();
	print("Broke on '%c'\n", c);

	words: list of ref Word[Int].String;

	smiley := "☺";
	frowny := ":(";

	sword := ref Word[Int].String(Int(5), smiley);

	# Format is: Adt[Type].PickTag(fields...)
	words = sword :: words;
	words = ref Word[Int].String(Int(7), frowny) :: words;

	if(ismember(sword, words))
		print("Found %d!\n", sword.w.d);

	exit;
}

# Skip white space
Rd[T].ws(rd: self ref Rd[T]): int {
	while(isspace(c := rd.t.getb()))
		{}

	return c;
}

Word[T].eq(a, b: ref Word): int
{
	return a.w == b.w;	# This is a shallow comparison, don't rely on this
}

# Matches whitespace characters
isspace(c: int): int {
	return c == ' ' || c == '\r' || c == '\t' || c == '\n';
}

# Checks if x is a member of l
ismember[T](x: T, l: list of T): int
	for {
		T =>	eq:	fn(a, b: T): int;
	}
{
	for(; l != nil; l = tl l)
		if(T.eq(x, hd l))
			return 1;

	return 0;
}

# Pairs two lists of separate types(?)
pair[T1, T2](l1: list of T1, l2: list of T2): list of (T1, T2) {
	if(l1 == nil && l2 == nil)
		return nil;

	return (hd l1, hd l2) :: pair(tl l1, tl l2);
}

# Reverse a list
rev[T](l: list of T): list of T {
	r: list of T;
	for(; l != nil; l = tl l)
		r = hd l :: r;

	return r;
}