ts-type-level-scheme
v0.0.4
Published
Type-level Scheme interpreter in TypeScript
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ts-type-level-scheme
Type-level Scheme interpreter in TypeScript.
import type { Scheme } from "ts-type-level-scheme";
type Reverse<array extends unknown[]> = [
"begin",
[
"define",
["reverse", "rest", "result"],
[
"if",
["null?", "rest"],
"result",
["reverse", ["cdr", "rest"], ["cons", ["car", "rest"], "result"]]
]
],
["reverse", ["quote", array], ["quote", []]]
];
type reversed = Scheme<Reverse<[1, "a", true, null, undefined]>>;
// ^? type reversed = [undefined, null, true, "a", 1]
import type { Scheme } from "ts-type-level-scheme";
type Fib<n extends number> = [
"begin",
[
"define",
["fib", "n"],
[
"cond",
[["=", "n", 0], 0],
[["=", "n", 1], 1],
["else", ["+", ["fib", ["-", "n", 1]], ["fib", ["-", "n", 2]]]]
]
],
["fib", n]
];
type fib_0 = Scheme<Fib<0>>;
// ^? type fib_0 = 0
type fib_1 = Scheme<Fib<1>>;
// ^? type fib_1 = 1
type fib_2 = Scheme<Fib<2>>;
// ^? type fib_2 = 1
type fib_3 = Scheme<Fib<3>>;
// ^? type fib_3 = 2
type fib_4 = Scheme<Fib<4>>;
// ^? type fib_4 = 3
type fib_5 = Scheme<Fib<5>>;
// ^? type fib_5 = 5
type fib_6 = Scheme<Fib<6>>;
// ^? type fib_6 = 8
Limitations
set!
,set-car!
, andset-cdr!
are not implemented.- Only the following special forms are available:
quote
define
if
lambda
cond
begin
- Only natural numbers including zero are supported for numbers.
- Due to the limitation of tsc, heavy computation will result in TS2589 error.
- Only the following primitive procedures can be used:
+
-
*
/
remainder
=
<
<=
>
>=
and
or
null?
cons
car
cdr
list
append
License
MIT