feat(builtins): add list, predicate, string, and i/o primitives
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+236
@@ -133,4 +133,240 @@ func installBuiltins(into env: Environment, interp: Interpreter) {
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def("odd?") { args in .bool(try intArg(args[0], "odd?") % 2 != 0) }
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def("1+") { args in numToValue(numAdd(try asNum(args[0], "1+"), .int(1))) }
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def("1-") { args in numToValue(numSub(try asNum(args[0], "1-"), .int(1))) }
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def("cons") { args in cons(args[0], args[1]) }
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func pairArg(_ v: Value, _ who: String) throws -> Pair {
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guard case .pair(let p) = v else { throw schemeError("\(who): expected pair", [v]) }
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return p
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}
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def("car") { args in try pairArg(args[0], "car").car }
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def("cdr") { args in try pairArg(args[0], "cdr").cdr }
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def("caar") { args in try pairArg(try pairArg(args[0], "caar").car, "caar").car }
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def("cadr") { args in try pairArg(try pairArg(args[0], "cadr").cdr, "cadr").car }
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def("cdar") { args in try pairArg(try pairArg(args[0], "cdar").car, "cdar").cdr }
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def("cddr") { args in try pairArg(try pairArg(args[0], "cddr").cdr, "cddr").cdr }
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def("caddr") { args in
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let d = try pairArg(args[0], "caddr").cdr
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let dd = try pairArg(d, "caddr").cdr
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return try pairArg(dd, "caddr").car
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}
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def("cadddr") { args in
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let d = try pairArg(args[0], "cadddr").cdr
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let dd = try pairArg(d, "cadddr").cdr
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let ddd = try pairArg(dd, "cadddr").cdr
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return try pairArg(ddd, "cadddr").car
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}
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def("set-car!") { args in try pairArg(args[0], "set-car!").car = args[1]; return .unspecified }
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def("set-cdr!") { args in try pairArg(args[0], "set-cdr!").cdr = args[1]; return .unspecified }
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def("list") { args in arrayToList(args) }
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def("length") { args in .integer(try listToArray(args[0]).count) }
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def("reverse") { args in arrayToList(try listToArray(args[0]).reversed()) }
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def("append") { args in
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if args.isEmpty { return .null }
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var result = args[args.count - 1]
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for list in args[0..<(args.count - 1)].reversed() {
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let items = try listToArray(list)
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result = arrayToList(items, tail: result)
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}
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return result
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}
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def("list-ref") { args in
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let items = try listToArray(args[0])
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let i = try intArg(args[1], "list-ref")
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guard i >= 0, i < items.count else { throw schemeError("list-ref: index out of range") }
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return items[i]
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}
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def("list-tail") { args in
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var cur = args[0]
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let k = try intArg(args[1], "list-tail")
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for _ in 0..<k {
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guard case .pair(let p) = cur else { throw schemeError("list-tail: index out of range") }
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cur = p.cdr
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}
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return cur
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}
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def("list-copy") { args in arrayToList(try listToArray(args[0])) }
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def("map") { args in
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let proc = args[0]
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let lists = try args[1...].map { try listToArray($0) }
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let n = lists.map { $0.count }.min() ?? 0
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var out: [Value] = []
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for i in 0..<n {
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out.append(try interp.applyProcedure(proc, lists.map { $0[i] }))
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}
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return arrayToList(out)
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}
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def("for-each") { args in
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let proc = args[0]
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let lists = try args[1...].map { try listToArray($0) }
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let n = lists.map { $0.count }.min() ?? 0
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for i in 0..<n {
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_ = try interp.applyProcedure(proc, lists.map { $0[i] })
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}
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return .unspecified
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}
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def("filter") { args in
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let proc = args[0]
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var out: [Value] = []
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for item in try listToArray(args[1]) where isTruthy(try interp.applyProcedure(proc, [item])) {
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out.append(item)
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}
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return arrayToList(out)
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}
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def("fold-left") { args in
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let proc = args[0]
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var acc = args[1]
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for item in try listToArray(args[2]) {
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acc = try interp.applyProcedure(proc, [acc, item])
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}
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return acc
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}
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def("fold-right") { args in
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let proc = args[0]
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var acc = args[1]
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for item in try listToArray(args[2]).reversed() {
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acc = try interp.applyProcedure(proc, [item, acc])
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}
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return acc
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}
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func memberBy(_ pred: @escaping (Value, Value) -> Bool) -> ([Value]) throws -> Value {
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return { args in
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var cur = args[1]
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while case .pair(let p) = cur {
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if pred(args[0], p.car) { return cur }
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cur = p.cdr
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}
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return .bool(false)
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}
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}
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def("member", .none, memberBy(equalValues))
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def("memq", .none, memberBy(eqv))
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def("memv", .none, memberBy(eqv))
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func assocBy(_ pred: @escaping (Value, Value) -> Bool) -> ([Value]) throws -> Value {
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return { args in
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var cur = args[1]
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while case .pair(let p) = cur {
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if case .pair(let entry) = p.car, pred(args[0], entry.car) { return p.car }
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cur = p.cdr
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}
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return .bool(false)
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}
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}
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def("assoc", .none, assocBy(equalValues))
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def("assq", .none, assocBy(eqv))
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def("assv", .none, assocBy(eqv))
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def("null?") { args in if case .null = args[0] { return .bool(true) }; return .bool(false) }
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def("pair?") { args in if case .pair = args[0] { return .bool(true) }; return .bool(false) }
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def("list?") { args in .bool(isProperList(args[0])) }
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def("symbol?") { args in if case .symbol = args[0] { return .bool(true) }; return .bool(false) }
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def("string?") { args in if case .string = args[0] { return .bool(true) }; return .bool(false) }
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def("char?") { args in if case .char = args[0] { return .bool(true) }; return .bool(false) }
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def("boolean?") { args in if case .bool = args[0] { return .bool(true) }; return .bool(false) }
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def("number?") { args in
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switch args[0] {
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case .integer, .rational, .real: return .bool(true)
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default: return .bool(false)
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}
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}
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def("integer?") { args in if case .integer = args[0] { return .bool(true) }; return .bool(false) }
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def("procedure?") { args in
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switch args[0] {
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case .builtin, .closure, .continuation: return .bool(true)
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default: return .bool(false)
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}
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}
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def("not") { args in .bool(!isTruthy(args[0])) }
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def("eq?") { args in .bool(eqv(args[0], args[1])) }
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def("eqv?") { args in .bool(eqv(args[0], args[1])) }
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def("equal?") { args in .bool(equalValues(args[0], args[1])) }
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def("display") { [weak interp] args in interp?.output(displayString(args[0])); return .unspecified }
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def("write") { [weak interp] args in interp?.output(writeString(args[0])); return .unspecified }
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def("newline") { [weak interp] _ in interp?.output("\n"); return .unspecified }
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def("error") { args in
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let message: String
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if let first = args.first, case .string(let s) = first { message = s }
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else if let first = args.first { message = writeString(first) }
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else { message = "error" }
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throw schemeError(message, Array(args.dropFirst()))
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}
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def("apply", .apply) { _ in .unspecified }
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def("call-with-current-continuation", .callCC) { _ in .unspecified }
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def("call/cc", .callCC) { _ in .unspecified }
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def("string-length") { args in
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guard case .string(let s) = args[0] else { throw schemeError("string-length: expected string") }
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return .integer(s.count)
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}
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def("string-append") { args in
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var out = ""
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for a in args {
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guard case .string(let s) = a else { throw schemeError("string-append: expected string") }
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out += s
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}
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return .string(out)
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}
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def("substring") { args in
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guard case .string(let s) = args[0] else { throw schemeError("substring: expected string") }
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let chars = Array(s)
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let start = try intArg(args[1], "substring")
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let end = args.count > 2 ? try intArg(args[2], "substring") : chars.count
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guard start >= 0, end <= chars.count, start <= end else { throw schemeError("substring: range error") }
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return .string(String(chars[start..<end]))
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}
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def("string=?") { args in
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guard case .string(let a) = args[0], case .string(let b) = args[1] else {
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throw schemeError("string=?: expected strings")
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}
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return .bool(a == b)
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}
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def("string->symbol") { args in
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guard case .string(let s) = args[0] else { throw schemeError("string->symbol: expected string") }
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return .symbol(s)
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}
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def("symbol->string") { args in
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guard case .symbol(let s) = args[0] else { throw schemeError("symbol->string: expected symbol") }
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return .string(baseName(s))
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}
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def("number->string") { args in .string(displayString(args[0])) }
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def("string->number") { args in
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guard case .string(let s) = args[0] else { throw schemeError("string->number: expected string") }
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if let n = parseInteger(s) { return .integer(n) }
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if let rat = parseRational(s) { return rat }
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if let d = parseReal(s) { return .real(d) }
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return .bool(false)
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}
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def("char->integer") { args in
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guard case .char(let c) = args[0], let scalar = c.unicodeScalars.first else {
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throw schemeError("char->integer: expected char")
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}
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return .integer(Int(scalar.value))
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}
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def("integer->char") { args in
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let n = try intArg(args[0], "integer->char")
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guard let scalar = Unicode.Scalar(UInt32(n)) else { throw schemeError("integer->char: out of range") }
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return .char(Character(scalar))
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}
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def("char=?") { args in
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guard case .char(let a) = args[0], case .char(let b) = args[1] else {
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throw schemeError("char=?: expected chars")
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}
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return .bool(a == b)
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}
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def("exact->inexact") { args in .real(numToDouble(try asNum(args[0], "exact->inexact"))) }
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def("inexact->exact") { args in
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switch args[0] {
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case .integer, .rational: return args[0]
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case .real(let d):
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if d == d.rounded() { return .integer(Int(d)) }
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return args[0]
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default: throw schemeError("inexact->exact: expected number")
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}
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}
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}
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