48 lines
1.4 KiB
Swift
48 lines
1.4 KiB
Swift
import XCTest
|
|
@testable import KiteCore
|
|
|
|
final class CallCCTests: XCTestCase {
|
|
private func evalShow(_ src: String) throws -> String {
|
|
displayString(try Interpreter().evalString(src))
|
|
}
|
|
|
|
func testEarlyExit() throws {
|
|
let program = """
|
|
(define (product items)
|
|
(call/cc
|
|
(lambda (break)
|
|
(let loop ((xs items) (acc 1))
|
|
(cond ((null? xs) acc)
|
|
((= (car xs) 0) (break 0))
|
|
(else (loop (cdr xs) (* acc (car xs)))))))))
|
|
(list (product '(1 2 3 4)) (product '(1 2 0 4)))
|
|
"""
|
|
XCTAssertEqual(try evalShow(program), "(24 0)")
|
|
}
|
|
|
|
func testContinuationValueWhenNotInvoked() throws {
|
|
XCTAssertEqual(try evalShow("(+ 1 (call/cc (lambda (k) 10)))"), "11")
|
|
}
|
|
|
|
func testReentrantContinuationLoop() throws {
|
|
let program = """
|
|
(let ((sum 0) (i 0) (k #f))
|
|
(call/cc (lambda (c) (set! k c)))
|
|
(set! i (+ i 1))
|
|
(set! sum (+ sum i))
|
|
(if (< i 5) (k #f) sum))
|
|
"""
|
|
XCTAssertEqual(try evalShow(program), "15")
|
|
}
|
|
|
|
func testMultiShotContinuationAccumulates() throws {
|
|
let program = """
|
|
(let ((results '()) (k #f) (n 0))
|
|
(set! n (+ 1 (call/cc (lambda (c) (set! k c) 0))))
|
|
(set! results (cons n results))
|
|
(if (< n 4) (k n) results))
|
|
"""
|
|
XCTAssertEqual(try evalShow(program), "(4 3 2 1)")
|
|
}
|
|
}
|