1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745
//! //! GetField reference (like a member pointer to non-static data field in C++) for Rust //! //! # Examples //! //! Subfield of type `U` which is contained by `T` can be obtained via `FieldRef<T, U>`. //! //! ``` //! use field_ref::{GetField, GetFieldMut, field_ref_of}; //! //! struct Foo(u32, u32, f64); //! struct Bar { //! foo: Foo, //! x: u32, //! } //! //! # fn main() { //! let fr1 = field_ref_of!(Bar => x); //! let fr2 = field_ref_of!(Bar => foo); //! let fr3 = field_ref_of!(Foo => 1); //! let fr4 = field_ref_of!(Bar => foo => 0); //! //! let mut bar = Bar { foo: Foo(10, 20, 0.5), x: 30 }; //! //! assert_eq!(bar.get_field(fr1), &30); //! assert_eq!(fr1.get(&bar), &30); //! //! *bar.get_field_mut(fr1) = 100; //! assert_eq!(bar.x, 100); //! //! *fr1.get_mut(&mut bar) = 200; //! assert_eq!(bar.x, 200); //! //! assert_eq!(bar.get_field(fr2.chain(fr3)), &20); //! assert_eq!(bar.get_field(fr4), &10); //! # } //! ``` //! //! Enum field of type `T` can be obtain as `Option<&T>` via `OptionFieldRef`. //! Other field such as struct field of type `T` can also be obtain as `Option<&T>` via `OptionFieldRef`. //! //! ``` //! use field_ref::{GetField, GetFieldMut, OptionFieldRef, opt_field_ref_of}; //! //! struct Foo { //! x: i32, //! y: f64, //! } //! //! enum E1 { //! A(i32), //! B(i32, Foo), //! } //! //! enum E2 { //! X(E1), //! Y, //! } //! //! # fn main() { //! let fr1 = opt_field_ref_of!(E1::A{0}); //! let fr2 = opt_field_ref_of!(E2::X{0} & E1::B{1} => y); //! let fr3 = opt_field_ref_of!(Foo => x); //! //! let e1_1 = E1::A(10); //! let e1_2 = E1::B(20, Foo{ x: 25, y: 2.5 }); //! let e2_1 = E2::X(E1::B(10, Foo{ x: 30, y: 3.5 })); //! let e2_2 = E2::Y; //! //! let mut foo = Foo{ x: 40, y: 4.5 }; //! //! assert_eq!(e1_1.try_get_field(fr1), Some(&10)); //! assert_eq!(e1_2.try_get_field(fr1), None); //! //! assert_eq!(e2_1.try_get_field(fr2), Some(&3.5)); //! assert_eq!(e2_2.try_get_field(fr2), None); //! //! assert_eq!(foo.try_get_field(fr3), Some(&40)); //! *foo.try_get_field_mut(fr3).unwrap() = 50; //! assert_eq!(foo.x, 50) //! # } //! ``` //! use std::marker::PhantomData; use std::cmp::{Eq, PartialEq, Ord, PartialOrd, Ordering}; /// /// A reference to field of type `U` (recursively) contained by an object of type `T`. /// pub struct FieldRef<T, U> { offset: usize, phantom: PhantomData<(T, U)>, } impl<T, U> FieldRef<T, U> { /// Creates a new `FieldRef` with offset bytes from the first byte of an object of type `T`. /// /// # Examples /// /// ``` /// use field_ref::FieldRef; /// /// #[repr(C)] /// struct Foo(u32, u32); /// /// # fn main() { /// // references Foo.1 /// let fr = unsafe { FieldRef::<Foo, u32>::from_offset(4) }; /// let foo = Foo(10, 20); /// assert_eq!(fr.get(&foo), &20); /// # } /// ``` pub unsafe fn from_offset(offset: usize) -> Self { Self { offset, phantom: PhantomData } } /// Creates a new `FieldRef` from a reference to concrete object of type `T` and a reference to concrete field of type `U`. /// /// # Examples /// /// ``` /// use field_ref::FieldRef; /// /// struct Foo(u32, u32, f64); /// /// # fn main() { /// let foo1 = Foo(10, 20, 0.5); /// let foo2 = Foo(30, 40, 1.5); /// let fr = unsafe { FieldRef::from_pointers(&foo1, &foo1.1) }; /// assert_eq!(fr.get(&foo2), &40); /// # } /// ``` pub unsafe fn from_pointers(obj: *const T, field: *const U) -> Self { Self::from_offset(field as usize - obj as usize) } /// Creates a new `FieldRef` from a pointer to concrete object of type `T` and a pointer to concrete field of type `U`. /// /// # Examples /// /// ``` /// use field_ref::FieldRef; /// /// struct Foo(u32, u32, f64); /// /// # fn main() { /// let foo1 = Foo(10, 20, 0.5); /// let foo2 = Foo(30, 40, 1.5); /// let fr = unsafe { FieldRef::from_references(&foo1, &foo1.1) }; /// assert_eq!(fr.get(&foo2), &40); /// # } /// ``` pub unsafe fn from_references(obj: &T, field: &U) -> Self { Self::from_pointers(obj, field) } /// Get the offset of target field. pub fn offset(&self) -> usize { self.offset } /// Get a reference of value in an object to which `FieldRef` refers. /// /// # Examples /// /// ``` /// use field_ref::field_ref_of; /// /// struct Foo(u32, u32, f64); /// /// # fn main() { /// let fr = field_ref_of!(Foo => 1); /// let foo = Foo(10, 20, 0.5); /// assert_eq!(fr.get(&foo), &20); /// # } /// ``` pub fn get<'a, 'b>(&'a self, obj: &'b T) -> &'b U { let addr = obj as *const _ as usize + self.offset; unsafe { &*(addr as *const U) } } #[deprecated(note = "Use `get` instead")] pub fn get_ref<'a, 'b>(&'a self, obj: &'b T) -> &'b U { self.get(obj) } /// Get a mutable reference of value in an object to which `FieldRef` refers. /// /// # Examples /// /// ``` /// use field_ref::field_ref_of; /// /// struct Foo(u32, u32, f64); /// /// # fn main() { /// let fr = field_ref_of!(Foo => 1); /// let mut foo = Foo(10, 20, 0.5); /// *fr.get_mut(&mut foo) = 30; /// assert_eq!(foo.1, 30); /// # } /// ``` pub fn get_mut<'a, 'b>(&'a self, obj: &'b mut T) -> &'b mut U { let addr = obj as *mut _ as usize + self.offset; unsafe { &mut *(addr as *mut U) } } /// Chains two field references. /// /// # Examples /// /// ``` /// use field_ref::field_ref_of; /// /// struct Foo(u32, u32, f64); /// struct Bar { /// foo: Foo, /// x: u32, /// } /// /// # fn main() { /// let fr1 = field_ref_of!(Bar => foo); /// let fr2 = field_ref_of!(Foo => 1); /// let bar = Bar { foo: Foo(10, 20, 0.5), x: 30 }; /// assert_eq!(fr1.chain(fr2).get(&bar), &20); /// # } /// ``` pub fn chain<V>(&self, fr: FieldRef<U, V>) -> FieldRef<T, V> { unsafe { FieldRef::<T, V>::from_offset(self.offset + fr.offset) } } /// Convert `FieldRef<T, U>` into an instance of trait `OptionFieldRef<'x, Input = T, Output = U>`. pub fn as_opt_field_ref(&self) -> FieldRefAsOptionFieldRef<T, U> { FieldRefAsOptionFieldRef(*self) } } impl<T, U> Clone for FieldRef<T, U> { fn clone(&self) -> Self { Self { offset: self.offset, phantom: PhantomData } } } impl<T, U> Copy for FieldRef<T, U> {} impl<T, U> std::fmt::Debug for FieldRef<T, U> { fn fmt(&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> { write!(f, "FieldRef {{ offset: {} }}", self.offset) } } impl<T, U> PartialEq for FieldRef<T, U> { fn eq(&self, other: &Self) -> bool { self.offset == other.offset } } impl<T, U> Eq for FieldRef<T, U> {} impl<T, U> PartialOrd for FieldRef<T, U> { fn partial_cmp(&self, other: &Self) -> Option<Ordering> { self.offset.partial_cmp(&other.offset) } } impl<T, U> Ord for FieldRef<T, U> { fn cmp(&self, other: &Self) -> Ordering { self.offset.cmp(&other.offset) } } /// /// A reference to field of type `Input` (recursively) contained by an object of type `Output` /// and that may fail dereference. /// pub trait OptionFieldRef<'x> where Self: Copy { type Input; type Output; /// Get a reference of value in an object to which `OptionFieldRef` refers. /// /// # Examples /// /// ``` /// use field_ref::{OptionFieldRef, opt_field_ref_of}; /// /// enum E { /// A(i32, char), /// B(i32) /// } /// /// # fn main() { /// let fr = opt_field_ref_of!(E::A{0}); /// let e1 = E::A(10, 'a'); /// let e2 = E::B(20); /// assert_eq!(fr.get(&e1), Some(&10)); /// assert_eq!(fr.get(&e2), None); /// # } /// ``` fn get<'a>(&'a self, obj: &'x Self::Input) -> Option<&'x Self::Output>; /// Get a mutable reference of value in an object to which `OptionFieldRef` refers. /// /// # Examples /// /// ``` /// use field_ref::{OptionFieldRef, opt_field_ref_of}; /// /// #[derive(Debug, Eq, PartialEq)] /// enum E { /// A(i32, char), /// B(i32) /// } /// /// # fn main() { /// let fr = opt_field_ref_of!(E::B{0}); /// let mut e = E::B(10); /// *fr.get_mut(&mut e).unwrap() = 20; /// assert_eq!(e, E::B(20)); /// # } /// ``` fn get_mut<'a>(&'a self, obj: &'x mut Self::Input) -> Option<&'x mut Self::Output>; /// Chains two field references. /// /// # Examples /// /// ``` /// use field_ref::{OptionFieldRef, opt_field_ref_of}; /// /// enum E1 { /// A(i32), /// B(i32, char), /// } /// /// enum E2 { /// X(E1), /// Y, /// } /// /// # fn main() { /// let fr1 = opt_field_ref_of!(E2::X{0}); /// let fr2 = opt_field_ref_of!(E1::A{0}); /// let e2 = E2::X(E1::A(10)); /// assert_eq!(fr1.chain(fr2).get(&e2), Some(&10)); /// # } /// ``` fn chain<FR, R: 'x>(&self, fr: FR) -> OptionFieldRefChain<Self, FR> where FR: OptionFieldRef<'x, Input = Self::Output, Output = R> + Copy { OptionFieldRefChain(*self, fr) } } /// /// A `OptionFieldRef` references a field within an enum constant. /// pub struct EnumFieldRef<E, T> { extractor: fn(&E) -> Option<&T>, mut_extractor: fn(&mut E) -> Option<&mut T>, } impl<E, T> EnumFieldRef<E, T> { /// Creates a new `EnumFieldRef` from a field extracting function and a mutable field extracting function. pub fn new(extractor: fn(&E) -> Option<&T>, mut_extractor: fn(&mut E) -> Option<&mut T>) -> Self { Self { extractor, mut_extractor } } } impl<'x, E: 'x, T: 'x> OptionFieldRef<'x> for EnumFieldRef<E, T> { type Input = E; type Output = T; fn get<'a>(&'a self, e: &'x Self::Input) -> Option<&'x Self::Output> { (self.extractor)(e) } fn get_mut<'a>(&'a self, e: &'x mut Self::Input) -> Option<&'x mut Self::Output> { (self.mut_extractor)(e) } } impl<E, T> Clone for EnumFieldRef<E, T> { fn clone(&self) -> Self { Self { extractor: self.extractor, mut_extractor: self.mut_extractor } } } impl<E, T> Copy for EnumFieldRef<E, T> {} /// /// A `OptionFieldRef` which chains two `OptionFieldRef`s. /// pub struct OptionFieldRefChain<FR1: Copy, FR2: Copy>(FR1, FR2); impl<'x, T: 'x, U: 'x, V: 'x, FR1, FR2> OptionFieldRef<'x> for OptionFieldRefChain<FR1, FR2> where FR1: OptionFieldRef<'x, Input = T, Output = U>, FR2: OptionFieldRef<'x, Input = U, Output = V>, { type Input = T; type Output = V; fn get<'a>(&'a self, obj: &'x Self::Input) -> Option<&'x Self::Output> { self.0.get(obj).and_then(|y| self.1.get(y)) } fn get_mut<'a>(&'a self, obj: &'x mut Self::Input) -> Option<&'x mut Self::Output> { self.0.get_mut(obj).and_then(|y| self.1.get_mut(y)) } } impl <FR1: Copy, FR2: Copy> Clone for OptionFieldRefChain<FR1, FR2> { fn clone(&self) -> Self { OptionFieldRefChain(self.0, self.1) } } impl <FR1: Copy, FR2: Copy> Copy for OptionFieldRefChain<FR1, FR2> {} /// /// A `OptionFieldRef` which converted from A `FieldRef`. /// pub struct FieldRefAsOptionFieldRef<T, U>(FieldRef<T, U>); impl<'x, T, U> OptionFieldRef<'x> for FieldRefAsOptionFieldRef<T, U> { type Input = T; type Output = U; fn get<'a>(&'a self, obj: &'x Self::Input) -> Option<&'x Self::Output> { Some(self.0.get(obj)) } fn get_mut<'a>(&'a self, obj: &'x mut Self::Input) -> Option<&'x mut Self::Output> { Some(self.0.get_mut(obj)) } } impl<T, U> Clone for FieldRefAsOptionFieldRef<T, U> { fn clone(&self) -> Self { FieldRefAsOptionFieldRef(self.0) } } impl<T, U> Copy for FieldRefAsOptionFieldRef<T, U> {} /// /// A trait to obtain a value to which `FieldRef` references via description like `obj.get_field(field_ref)`. /// pub trait GetField where Self: Sized { /// # Examples /// /// ``` /// use field_ref::{GetField, field_ref_of}; /// /// struct Foo(u32, u32, f64); /// /// # fn main() { /// let fr = field_ref_of!(Foo => 1); /// let foo = Foo(10, 20, 0.5); /// assert_eq!(foo.get_field(fr), &20); /// # } /// ``` fn get_field<T>(&self, fr: FieldRef<Self, T>) -> &T; fn try_get_field<'x, FR, T>(&'x self, fr: FR) -> Option<&'x T> where FR: OptionFieldRef<'x, Input = Self, Output = T>; } /// /// Creates a new `FieldRef` from basic type and fields which are (recursively) contained by that type. /// /// # Examples /// /// ``` /// use field_ref::{FieldRef, field_ref_of}; /// /// struct Foo(u32, u32); /// /// # fn main() { /// // references Foo.1 /// let fr = field_ref_of!(Foo => 1); /// let foo = Foo(10, 20); /// assert_eq!(fr.get(&foo), &20); /// # } /// ``` #[macro_export] macro_rules! field_ref_of { ($t:ty $(=> $f:tt)+) => { unsafe { let base = ::std::ptr::null() as *const $t; $crate::FieldRef::from_pointers(base, &(*base)$(.$f)+) } }; } /// /// A trait to obtain a mutable value to which `FieldRef` references via description like `obj.get_field_mut(field_ref)`. /// pub trait GetFieldMut where Self: Sized { /// # Examples /// /// ``` /// use field_ref::{GetFieldMut, field_ref_of}; /// /// struct Foo(u32, u32, f64); /// /// # fn main() { /// let fr = field_ref_of!(Foo => 1); /// let mut foo = Foo(10, 20, 0.5); /// *foo.get_field_mut(fr) = 30; /// assert_eq!(foo.1, 30); /// # } /// ``` fn get_field_mut<T>(&mut self, fr: FieldRef<Self, T>) -> &mut T; fn try_get_field_mut<'x, FR, T>(&'x mut self, fr: FR) -> Option<&'x mut T> where FR: OptionFieldRef<'x, Input = Self, Output = T>; } impl<S: Sized> GetField for S { fn get_field<T>(&self, fr: FieldRef<Self, T>) -> &T { fr.get(self) } fn try_get_field<'x, FR, T>(&'x self, fr: FR) -> Option<&'x T> where FR: OptionFieldRef<'x, Input = Self, Output = T> { fr.get(self) } } impl<S: Sized> GetFieldMut for S { fn get_field_mut<T>(&mut self, fr: FieldRef<Self, T>) -> &mut T { fr.get_mut(self) } fn try_get_field_mut<'x, FR, T>(&'x mut self, fr: FR) -> Option<&'x mut T> where FR: OptionFieldRef<'x, Input = Self, Output = T> { fr.get_mut(self) } } /// Creates a new instance of `OptionFieldRef` from basic type (enum constansts, structs or tuples) and these fields. /// /// # Examples /// /// ``` /// use field_ref::{GetField, GetFieldMut, OptionFieldRef, opt_field_ref_of}; /// /// struct Foo { /// x: i32, /// y: f64, /// } /// /// enum E1 { /// A(i32), /// B(i32, Foo), /// } /// /// enum E2 { /// X(E1), /// Y, /// } /// /// # fn main() { /// let fr1 = opt_field_ref_of!(E1::A{0}); /// let fr2 = opt_field_ref_of!(E2::X{0} & E1::B{1} => y); /// let fr3 = opt_field_ref_of!(Foo => x); /// /// let e1_1 = E1::A(10); /// let e1_2 = E1::B(20, Foo{ x: 25, y: 2.5 }); /// let e2_1 = E2::X(E1::B(10, Foo{ x: 30, y: 3.5 })); /// let e2_2 = E2::Y; /// /// let mut foo = Foo{ x: 40, y: 4.5 }; /// /// assert_eq!(e1_1.try_get_field(fr1), Some(&10)); /// assert_eq!(e1_2.try_get_field(fr1), None); /// /// assert_eq!(e2_1.try_get_field(fr2), Some(&3.5)); /// assert_eq!(e2_2.try_get_field(fr2), None); /// /// assert_eq!(foo.try_get_field(fr3), Some(&40)); /// *foo.try_get_field_mut(fr3).unwrap() = 50; /// assert_eq!(foo.x, 50) /// # } /// ``` #[macro_export] macro_rules! opt_field_ref_of { ($e:path { $f:tt } $(=> $fs:tt)*) => { $crate::EnumFieldRef::new( $crate::enum_field_extractor!($e => $f $(=> $fs)*), $crate::enum_field_extractor!($e => $f $(=> $fs)*, mut) ) }; ($e:path { $f:tt } $(=> $fs:tt)* & $($tts:tt)+) => { $crate::EnumFieldRef::new( $crate::enum_field_extractor!($e => $f $(=> $fs)*), $crate::enum_field_extractor!($e => $f $(=> $fs)*, mut) ) .chain($crate::opt_field_ref_of!($($tts)+)) }; ($t:ty $(=> $f:tt)+) => { $crate::field_ref_of!($t $(=> $f)+).as_opt_field_ref() }; ($t:ty $(=> $f:tt)+ & $($tts:tt)+) => { $crate::field_ref_of!($t $(=> $f)+).as_opt_field_ref() .chain($crate::opt_field_ref_of!($($tts)+)) }; } #[doc(hidden)] #[macro_export] macro_rules! enum_field_extractor { ($e:path => $f:tt $(=> $fs:tt)* $(, $mut:tt)*) => { #[allow(non_shorthand_field_patterns)] |e| if let &$($mut)* $e { $f: ref $($mut)* x, .. } = e { Some(&$($mut)*(*x) $(.$fs)*) } else { None } }; } #[cfg(test)] mod tests { use super::*; #[repr(C)] // to guarantee the result of Ord test struct Foo(u32, u32); struct Bar { foo: Foo, x: u32, } #[test] fn basic_test() { let mut foo = Foo(10, 20); let fr1 = field_ref_of!(Foo => 0); let fr2 = field_ref_of!(Foo => 1); assert_eq!(fr1.get(&foo), &10); assert_eq!(foo.get_field(fr2), &20); *fr2.get_mut(&mut foo) = 30; *foo.get_field_mut(fr1) = 40; assert_eq!(foo.0, 40); assert_eq!(foo.1, 30); } #[test] fn multi_level_test() { let bar = Bar{ foo: Foo(10, 20), x: 30 }; let fr1 = field_ref_of!(Bar => foo => 1); let fr2 = field_ref_of!(Bar => foo); let fr3 = field_ref_of!(Foo => 1); let fr4 = field_ref_of!(Bar => x); assert_eq!(bar.get_field(fr1), &20); assert_eq!(bar.get_field(fr2.chain(fr3)), &20); assert_eq!(bar.get_field(fr4), &30); } #[test] fn debug_test() { let fr = unsafe { FieldRef::<Foo, u32>::from_offset(100) }; assert_eq!(format!("{:?}", fr), "FieldRef { offset: 100 }"); } #[test] fn eq_test() { let fr1 = field_ref_of!(Bar => foo => 1); let fr2 = field_ref_of!(Bar => foo); let fr3 = field_ref_of!(Foo => 1); let fr4 = field_ref_of!(Bar => x); assert!(fr1 != fr4); assert!(fr1 == fr2.chain(fr3)); } #[test] fn ord_test() { let fr1 = field_ref_of!(Bar => foo => 0); let fr2 = field_ref_of!(Bar => foo => 1); let fr3 = field_ref_of!(Bar => foo); let fr4 = field_ref_of!(Foo => 1); assert_eq!(fr1.cmp(&fr2), Ordering::Less); assert_eq!(fr2.cmp(&fr1), Ordering::Greater); assert_eq!(fr2.cmp(&fr3.chain(fr4)), Ordering::Equal); } #[derive(Debug, Eq, PartialEq)] enum E { A(u32, u32), B{ x: u32, y: u32 }, C, } mod sub { #[allow(dead_code)] pub enum E2 { X(u32), Y, } } #[test] fn enum_field_basic_test() { let fr1 = opt_field_ref_of!(E::A{1}); let fr2 = opt_field_ref_of!(E::B{x}); let mut e1 = E::A(10, 20); let e2 = E::B{ x: 30, y: 40 }; let e3 = E::C; assert_eq!(fr1.get(&e1), Some(&20)); assert_eq!(fr1.get(&e2), None); assert_eq!(fr1.get(&e3), None); *fr1.get_mut(&mut e1).unwrap() = 100; assert_eq!(e1, E::A(10, 100)); assert_eq!(fr2.get(&e2), Some(&30)); } #[test] fn enum_field_enum_with_path_test() { let fr1 = opt_field_ref_of!(sub::E2::X{0}); let e1 = sub::E2::X(10); assert_eq!(fr1.get(&e1), Some(&10)); } }