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const std = @import("std");
const Value = @import("./value.zig").Value;
const Array = @import("./value.zig").Array;
const Object = @import("./value.zig").Object;
pub const OpsError = error{
InvalidType,
InternalError,
Unimplemented,
};
pub fn index(base: Value, key: Value) OpsError!Value {
return switch (base) {
.array => |a| switch (key) {
.integer => |i| a.get(@intCast(i)),
else => error.InvalidType,
},
.object => |o| switch (key) {
.string => |s| o.get(s) orelse Value.null,
else => error.InvalidType,
},
.null => Value.null,
else => error.InvalidType,
};
}
pub fn slice(allocator: std.mem.Allocator, base: Value, from: Value, to: Value) OpsError!Value {
switch (base) {
.array => |a| {
const len: i64 = @intCast(a.len());
var start: i64 = if (from == .null) 0 else if (from == .integer) from.integer else return error.InvalidType;
var end: i64 = if (to == .null) len else if (to == .integer) to.integer else return error.InvalidType;
if (start < 0) start += len;
if (end < 0) end += len;
start = @max(0, @min(start, len));
end = @max(0, @min(end, len));
if (start >= end) {
const empty = Array.init(allocator) catch return error.InternalError;
return Value.initArray(empty);
}
var result = Array.init(allocator) catch return error.InternalError;
const ustart: usize = @intCast(start);
const uend: usize = @intCast(end);
var i: usize = ustart;
while (i < uend) : (i += 1) {
result.append(allocator, a.get(i)) catch return error.InternalError;
}
return Value.initArray(result);
},
.string => |s| {
const len: i64 = @intCast(s.len);
var start: i64 = if (from == .null) 0 else if (from == .integer) from.integer else return error.InvalidType;
var end: i64 = if (to == .null) len else if (to == .integer) to.integer else return error.InvalidType;
if (start < 0) start += len;
if (end < 0) end += len;
start = @max(0, @min(start, len));
end = @max(0, @min(end, len));
if (start >= end) {
const duped = allocator.dupe(u8, "") catch return error.InternalError;
return Value.initString(duped);
}
const ustart: usize = @intCast(start);
const uend: usize = @intCast(end);
const duped = allocator.dupe(u8, s[ustart..uend]) catch return error.InternalError;
return Value.initString(duped);
},
.null => return .null,
else => return error.InvalidType,
}
}
pub const CompareOp = enum { eq, ne, lt, gt, le, ge };
pub fn compare(lhs: Value, rhs: Value, op: CompareOp) OpsError!bool {
const lhs_tag = lhs.kind();
const rhs_tag = rhs.kind();
if (lhs_tag != rhs_tag) {
const lhs_is_number = lhs_tag == .integer or lhs_tag == .float;
const rhs_is_number = rhs_tag == .integer or rhs_tag == .float;
if (lhs_is_number and rhs_is_number) {
return compareNumbers(lhs, rhs, op);
}
return error.InvalidType;
}
return switch (lhs) {
.null => switch (op) {
.eq => true,
.ne => false,
.lt, .gt, .le, .ge => error.Unimplemented,
},
.bool => |lhs_bool| {
const rhs_bool = rhs.bool;
return switch (op) {
.eq => lhs_bool == rhs_bool,
.ne => lhs_bool != rhs_bool,
.lt, .gt, .le, .ge => error.Unimplemented,
};
},
.integer, .float => compareNumbers(lhs, rhs, op),
.string => |lhs_str| {
const rhs_str = rhs.string;
const order = std.mem.order(u8, lhs_str, rhs_str);
return switch (op) {
.eq => order == .eq,
.ne => order != .eq,
.lt => order == .lt,
.gt => order == .gt,
.le => order == .lt or order == .eq,
.ge => order == .gt or order == .eq,
};
},
.array => switch (op) {
.eq, .ne => error.Unimplemented,
.lt, .gt, .le, .ge => error.Unimplemented,
},
.object => switch (op) {
.eq, .ne => error.Unimplemented,
.lt, .gt, .le, .ge => error.Unimplemented,
},
};
}
fn compareNumbers(lhs: Value, rhs: Value, op: CompareOp) bool {
const lhs_f: f64 = switch (lhs) {
.integer => |i| @floatFromInt(i),
.float => |f| f,
else => unreachable,
};
const rhs_f: f64 = switch (rhs) {
.integer => |i| @floatFromInt(i),
.float => |f| f,
else => unreachable,
};
return switch (op) {
.eq => lhs_f == rhs_f,
.ne => lhs_f != rhs_f,
.lt => lhs_f < rhs_f,
.gt => lhs_f > rhs_f,
.le => lhs_f <= rhs_f,
.ge => lhs_f >= rhs_f,
};
}
test "index array" {
var arr = try Array.init(std.testing.allocator);
defer arr.deinit(std.testing.allocator);
try arr.append(std.testing.allocator, Value.initInteger(10));
try arr.append(std.testing.allocator, Value.initInteger(20));
try arr.append(std.testing.allocator, Value.initInteger(30));
const base = Value.initArray(arr);
try std.testing.expectEqual(Value.initInteger(10), try index(base, Value.initInteger(0)));
try std.testing.expectEqual(Value.initInteger(20), try index(base, Value.initInteger(1)));
try std.testing.expectEqual(Value.initInteger(30), try index(base, Value.initInteger(2)));
try std.testing.expectEqual(Value.null, try index(base, Value.initInteger(3)));
}
test "index object" {
var obj = try Object.init(std.testing.allocator);
defer obj.deinit(std.testing.allocator);
try obj.set(std.testing.allocator, "foo", Value.initInteger(1));
try obj.set(std.testing.allocator, "bar", Value.initInteger(2));
const base = Value.initObject(obj);
try std.testing.expectEqual(Value.initInteger(1), try index(base, Value.initString("foo")));
try std.testing.expectEqual(Value.initInteger(2), try index(base, Value.initString("bar")));
try std.testing.expectEqual(Value.null, try index(base, Value.initString("baz")));
}
test "index null" {
try std.testing.expectEqual(Value.null, try index(Value.null, Value.initInteger(0)));
try std.testing.expectEqual(Value.null, try index(Value.null, Value.initString("foo")));
}
test "index invalid type" {
try std.testing.expectError(error.InvalidType, index(Value.initInteger(42), Value.initInteger(0)));
try std.testing.expectError(error.InvalidType, index(Value.initString("foo"), Value.initInteger(0)));
}
test "compare integers" {
try std.testing.expect(try compare(Value.initInteger(1), Value.initInteger(1), .eq));
try std.testing.expect(!try compare(Value.initInteger(1), Value.initInteger(2), .eq));
try std.testing.expect(try compare(Value.initInteger(1), Value.initInteger(2), .ne));
try std.testing.expect(try compare(Value.initInteger(1), Value.initInteger(2), .lt));
try std.testing.expect(try compare(Value.initInteger(2), Value.initInteger(1), .gt));
try std.testing.expect(try compare(Value.initInteger(1), Value.initInteger(1), .le));
try std.testing.expect(try compare(Value.initInteger(1), Value.initInteger(1), .ge));
}
test "compare floats" {
try std.testing.expect(try compare(Value.initFloat(1.5), Value.initFloat(1.5), .eq));
try std.testing.expect(try compare(Value.initFloat(1.5), Value.initFloat(2.5), .lt));
try std.testing.expect(try compare(Value.initFloat(2.5), Value.initFloat(1.5), .gt));
}
test "compare mixed numbers" {
try std.testing.expect(try compare(Value.initInteger(2), Value.initFloat(2.0), .eq));
try std.testing.expect(try compare(Value.initFloat(1.5), Value.initInteger(2), .lt));
try std.testing.expect(try compare(Value.initInteger(3), Value.initFloat(2.5), .gt));
}
test "compare strings" {
try std.testing.expect(try compare(Value.initString("abc"), Value.initString("abc"), .eq));
try std.testing.expect(try compare(Value.initString("abc"), Value.initString("abd"), .ne));
try std.testing.expect(try compare(Value.initString("abc"), Value.initString("abd"), .lt));
try std.testing.expect(try compare(Value.initString("abd"), Value.initString("abc"), .gt));
}
test "compare booleans" {
try std.testing.expect(try compare(Value.initBool(true), Value.initBool(true), .eq));
try std.testing.expect(try compare(Value.initBool(false), Value.initBool(false), .eq));
try std.testing.expect(try compare(Value.initBool(true), Value.initBool(false), .ne));
}
test "compare null" {
try std.testing.expect(try compare(Value.null, Value.null, .eq));
try std.testing.expect(!try compare(Value.null, Value.null, .ne));
}
test "compare different types" {
try std.testing.expectError(error.InvalidType, compare(Value.initInteger(1), Value.initString("1"), .eq));
try std.testing.expectError(error.InvalidType, compare(Value.null, Value.initInteger(0), .eq));
}
pub fn isFalsy(value: Value) bool {
return switch (value) {
.null => true,
.bool => |b| !b,
else => false,
};
}
pub fn isTruthy(value: Value) bool {
return !isFalsy(value);
}
test "isFalsy" {
try std.testing.expect(isFalsy(Value.null));
try std.testing.expect(isFalsy(Value.initBool(false)));
try std.testing.expect(!isFalsy(Value.initBool(true)));
try std.testing.expect(!isFalsy(Value.initInteger(0)));
try std.testing.expect(!isFalsy(Value.initInteger(1)));
try std.testing.expect(!isFalsy(Value.initString("")));
try std.testing.expect(!isFalsy(Value.initString("hello")));
}
test "isTruthy" {
try std.testing.expect(!isTruthy(Value.null));
try std.testing.expect(!isTruthy(Value.initBool(false)));
try std.testing.expect(isTruthy(Value.initBool(true)));
try std.testing.expect(isTruthy(Value.initInteger(0)));
try std.testing.expect(isTruthy(Value.initInteger(1)));
try std.testing.expect(isTruthy(Value.initString("")));
try std.testing.expect(isTruthy(Value.initString("hello")));
}
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