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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,
Unimplemented,
};
pub fn index(base: Value, key: Value) OpsError!Value {
return switch (base) {
.array => |arr| blk: {
const idx: usize = @intCast(switch (key) {
.integer => |i| i,
else => return error.InvalidType,
});
break :blk if (idx < arr.items.len) arr.items[idx] else .null;
},
.object => |obj| blk: {
const k = switch (key) {
.string => |s| s,
else => return error.InvalidType,
};
break :blk obj.get(k) orelse .null;
},
.null => .null,
else => 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 = std.meta.activeTag(lhs);
const rhs_tag = std.meta.activeTag(rhs);
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,
},
.number_string => 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 = Array.init(std.testing.allocator);
defer arr.deinit();
try arr.append(.{ .integer = 10 });
try arr.append(.{ .integer = 20 });
try arr.append(.{ .integer = 30 });
const base = Value{ .array = arr };
try std.testing.expectEqual(Value{ .integer = 10 }, try index(base, .{ .integer = 0 }));
try std.testing.expectEqual(Value{ .integer = 20 }, try index(base, .{ .integer = 1 }));
try std.testing.expectEqual(Value{ .integer = 30 }, try index(base, .{ .integer = 2 }));
try std.testing.expectEqual(Value.null, try index(base, .{ .integer = 3 }));
}
test "index object" {
var obj = Object.init(std.testing.allocator);
defer obj.deinit();
try obj.put("foo", .{ .integer = 1 });
try obj.put("bar", .{ .integer = 2 });
const base = Value{ .object = obj };
try std.testing.expectEqual(Value{ .integer = 1 }, try index(base, .{ .string = "foo" }));
try std.testing.expectEqual(Value{ .integer = 2 }, try index(base, .{ .string = "bar" }));
try std.testing.expectEqual(Value.null, try index(base, .{ .string = "baz" }));
}
test "index null" {
try std.testing.expectEqual(Value.null, try index(.null, .{ .integer = 0 }));
try std.testing.expectEqual(Value.null, try index(.null, .{ .string = "foo" }));
}
test "index invalid type" {
try std.testing.expectError(error.InvalidType, index(.{ .integer = 42 }, .{ .integer = 0 }));
try std.testing.expectError(error.InvalidType, index(.{ .string = "foo" }, .{ .integer = 0 }));
}
test "compare integers" {
try std.testing.expect(try compare(.{ .integer = 1 }, .{ .integer = 1 }, .eq));
try std.testing.expect(!try compare(.{ .integer = 1 }, .{ .integer = 2 }, .eq));
try std.testing.expect(try compare(.{ .integer = 1 }, .{ .integer = 2 }, .ne));
try std.testing.expect(try compare(.{ .integer = 1 }, .{ .integer = 2 }, .lt));
try std.testing.expect(try compare(.{ .integer = 2 }, .{ .integer = 1 }, .gt));
try std.testing.expect(try compare(.{ .integer = 1 }, .{ .integer = 1 }, .le));
try std.testing.expect(try compare(.{ .integer = 1 }, .{ .integer = 1 }, .ge));
}
test "compare floats" {
try std.testing.expect(try compare(.{ .float = 1.5 }, .{ .float = 1.5 }, .eq));
try std.testing.expect(try compare(.{ .float = 1.5 }, .{ .float = 2.5 }, .lt));
try std.testing.expect(try compare(.{ .float = 2.5 }, .{ .float = 1.5 }, .gt));
}
test "compare mixed numbers" {
try std.testing.expect(try compare(.{ .integer = 2 }, .{ .float = 2.0 }, .eq));
try std.testing.expect(try compare(.{ .float = 1.5 }, .{ .integer = 2 }, .lt));
try std.testing.expect(try compare(.{ .integer = 3 }, .{ .float = 2.5 }, .gt));
}
test "compare strings" {
try std.testing.expect(try compare(.{ .string = "abc" }, .{ .string = "abc" }, .eq));
try std.testing.expect(try compare(.{ .string = "abc" }, .{ .string = "abd" }, .ne));
try std.testing.expect(try compare(.{ .string = "abc" }, .{ .string = "abd" }, .lt));
try std.testing.expect(try compare(.{ .string = "abd" }, .{ .string = "abc" }, .gt));
}
test "compare booleans" {
try std.testing.expect(try compare(.{ .bool = true }, .{ .bool = true }, .eq));
try std.testing.expect(try compare(.{ .bool = false }, .{ .bool = false }, .eq));
try std.testing.expect(try compare(.{ .bool = true }, .{ .bool = false }, .ne));
}
test "compare null" {
try std.testing.expect(try compare(.null, .null, .eq));
try std.testing.expect(!try compare(.null, .null, .ne));
}
test "compare different types" {
try std.testing.expectError(error.InvalidType, compare(.{ .integer = 1 }, .{ .string = "1" }, .eq));
try std.testing.expectError(error.InvalidType, compare(.null, .{ .integer = 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(.null));
try std.testing.expect(isFalsy(.{ .bool = false }));
try std.testing.expect(!isFalsy(.{ .bool = true }));
try std.testing.expect(!isFalsy(.{ .integer = 0 }));
try std.testing.expect(!isFalsy(.{ .integer = 1 }));
try std.testing.expect(!isFalsy(.{ .string = "" }));
try std.testing.expect(!isFalsy(.{ .string = "hello" }));
}
test "isTruthy" {
try std.testing.expect(!isTruthy(.null));
try std.testing.expect(!isTruthy(.{ .bool = false }));
try std.testing.expect(isTruthy(.{ .bool = true }));
try std.testing.expect(isTruthy(.{ .integer = 0 }));
try std.testing.expect(isTruthy(.{ .integer = 1 }));
try std.testing.expect(isTruthy(.{ .string = "" }));
try std.testing.expect(isTruthy(.{ .string = "hello" }));
}
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