logo
  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
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
//!
//! A safe and user friendly R extension interface.
//!
//! * Build rust extensions to R.
//! * Convert R packages to Rust crates.
//!
//! This library aims to provide an interface that will be familiar to
//! first-time users of Rust or indeed any compiled language.
//!
//! See [Robj] for much of the content of this crate.
//! [Robj] provides a safe wrapper for the R object type.
//!
//! ## Examples
//!
//! Use attributes and macros to export to R.
//! ```ignore
//! use extendr_api::prelude::*;
//! // Export a function or impl to R.
//! #[extendr]
//! fn fred(a: i32) -> i32 {
//!     a + 1
//! }
//!
//! // define exports using extendr_module
//! extendr_module! {
//!    mod mymodule;
//!    fn fred;    
//! }
//!
//! ```
//!
//! In R:
//!
//! ```ignore
//! result <- fred(1)
//! ```
//!
//! [Robj] is a wrapper for R objects.
//! The r!() and R!() macros let you build R objects
//! using Rust and R syntax respectively.
//! ```
//! use extendr_api::prelude::*;
//! test! {
//!     // An R object with a single string "hello"
//!     let character = r!("hello");
//!     let character = r!(["hello", "goodbye"]);
//!    
//!     // An R integer object with a single number 1L.
//!     // Note that in Rust, 1 is an integer and 1.0 is a real.
//!     let integer = r!(1);
//!    
//!     // An R real object with a single number 1.
//!     // Note that in R, 1 is a real and 1L is an integer.
//!     let real = r!(1.0);
//!    
//!     // An R real vector.
//!     let real_vector = r!([1.0, 2.0]);
//!     let real_vector = &[1.0, 2.0].iter().collect_robj();
//!     let real_vector = r!(vec![1.0, 2.0]);
//!    
//!     // An R function object.
//!     let function = R!("function(x, y) { x + y }")?;
//!    
//!     // A named list using the list! macro.
//!     let list = list!(a = 1, b = 2);
//!    
//!     // An unnamed list (of R objects) using the List wrapper.
//!     let list = r!(List::from_values(vec![1, 2, 3]));
//!     let list = r!(List::from_values(vec!["a", "b", "c"]));
//!     let list = r!(List::from_values(&[r!("a"), r!(1), r!(2.0)]));
//!
//!     // A symbol
//!     let sym = sym!(wombat);
//!
//!     // A R vector using collect_robj()
//!     let vector = (0..3).map(|x| x * 10).collect_robj();
//! }
//! ```
//!
//! In Rust, we prefer to use iterators rather than loops.
//!
//! ```
//! use extendr_api::prelude::*;
//! test! {
//!     // 1 ..= 100 is the same as 1:100
//!     let res = r!(1 ..= 100);
//!     assert_eq!(res, R!("1:100")?);
//!    
//!     // Rust arrays are zero-indexed so it is more common to use 0 .. 100.
//!     let res = r!(0 .. 100);
//!     assert_eq!(res.len(), 100);
//!    
//!     // Using map is a super fast way to generate vectors.
//!     let iter = (0..3).map(|i| format!("fred{}", i));
//!     let character = iter.collect_robj();
//!     assert_eq!(character, r!(["fred0", "fred1", "fred2"]));
//! }
//! ```
//!
//! To index a vector, first convert it to a slice and then
//! remember to use 0-based indexing. In Rust, going out of bounds
//! will cause and error (a panic) unlike C++ which may crash.
//! ```
//! use extendr_api::prelude::*;
//! test! {
//!     let vals = r!([1.0, 2.0]);
//!     let slice = vals.as_real_slice().ok_or("expected slice")?;
//!     let one = slice[0];
//!     let two = slice[1];
//!     // let error = slice[2];
//!     assert_eq!(one, 1.0);
//!     assert_eq!(two, 2.0);
//! }
//! ```
//!
//! Much slower, but more general are these methods:
//! ```
//! use extendr_api::prelude::*;
//! test! {
//!     let vals = r!([1.0, 2.0, 3.0]);
//!    
//!     // one-based indexing [[i]], returns an object.
//!     assert_eq!(vals.index(1)?, r!(1.0));
//!    
//!     // one-based slicing [x], returns an object.
//!     assert_eq!(vals.slice(1..=2)?, r!([1.0, 2.0]));
//!    
//!     // $ operator, returns an object
//!     let list = list!(a = 1.0, b = "xyz");
//!     assert_eq!(list.dollar("a")?, r!(1.0));
//! }
//! ```
//!
//! The [R!] macro lets you embed R code in Rust
//! and takes Rust expressions in {{ }} pairs.
//!
//! The [Rraw!] macro will not expand the {{ }} pairs.
//! ```
//! use extendr_api::prelude::*;
//! test! {
//!     // The text "1 + 1" is parsed as R source code.
//!     // The result is 1.0 + 1.0 in Rust.
//!     assert_eq!(R!("1 + 1")?, r!(2.0));
//!
//!     let a = 1.0;
//!     assert_eq!(R!("1 + {{a}}")?, r!(2.0));
//!
//!     assert_eq!(R!(r"
//!         x <- {{ a }}
//!         x + 1
//!     ")?, r!(2.0));
//!
//!     assert_eq!(R!(r#"
//!         x <- "hello"
//!         x
//!     "#)?, r!("hello"));
//!
//!     // Use the R meaning of {{ }} and do not expand.
//!     assert_eq!(Rraw!(r"
//!         x <- {{ 1 }}
//!         x + 1
//!     ")?, r!(2.0));
//! }
//! ```
//!
//! The [r!] macro converts a rust object to an R object
//! and takes parameters.
//! ```
//! use extendr_api::prelude::*;
//! test! {
//!     // The text "1.0+1.0" is parsed as Rust source code.
//!     let one = 1.0;
//!     assert_eq!(r!(one+1.0), r!(2.0));
//! }
//! ```
//!
//! You can call R functions and primitives using the [call!] macro.
//! ```
//! use extendr_api::prelude::*;
//! test! {
//!
//!     // As one R! macro call
//!     let confint1 = R!("confint(lm(weight ~ group - 1, PlantGrowth))")?;
//!    
//!     // As many parameterized calls.
//!     let formula = lang!("~", sym!(weight), lang!("-", sym!(group), 1.0)).set_class(["formula"])?;
//!     let plant_growth = global!(PlantGrowth)?;
//!     let model = call!("lm", formula, plant_growth)?;
//!     let confint2 = call!("confint", model)?;
//!    
//!     assert_eq!(confint1.as_real_vector(), confint2.as_real_vector());
//! }
//! ```
//!
//! Rust has a concept of "Owned" and "Borrowed" objects.
//!
//! Owned objects, such as [Vec] and [String] allocate memory
//! which is released when the object lifetime ends.
//!
//! Borrowed objects such as &[i32] and &str are just pointers
//! to annother object's memory and can't live longer than the
//! object they reference.
//!
//! Borrowed objects are much faster than owned objects and use less
//! memory but are used only for temporary access.
//!
//! When we take a slice of an R vector, for example, we need the
//! original R object to be alive or the data will be corrupted.
//!
//! ```
//! use extendr_api::prelude::*;
//! test! {
//!     // robj is an "Owned" object that controls the memory allocated.
//!     let robj = r!([1, 2, 3]);
//!    
//!     // Here slice is a "borrowed" reference to the bytes in robj.
//!     // and cannot live longer than robj.
//!     let slice = robj.as_integer_slice().ok_or("expected slice")?;
//!     assert_eq!(slice.len(), 3);
//! }
//! ```
//!
//! ## Writing tests
//!
//! To test the functions exposed to R, wrap your code in the [`test!`] macro.
//! This macro starts up the necessary R machinery for tests to work.
//!
//! ```no_run
//! use extendr_api::prelude::*;
//!
//! #[extendr]
//! fn things() ->  Strings {
//!     Strings::from_values(vec!["Test", "this"])
//! }
//!
//! // define exports using extendr_module
//! extendr_module! {
//!    mod mymodule;
//!    fn things;    
//! }
//!
//!
//! #[cfg(test)]
//! mod test {
//!     use super::*;
//!     use extendr_api::prelude::*;
//!
//!     #[test]
//!     fn test_simple_function() {
//!         assert_eq!(things().elt(0), "Test")
//!     }
//! }
//! ```
//!
//! ## Feature gates
//!
//! extendr-api has some optional features behind these feature gates:
//!
//! - `ndarray`: provides the conversion between R's matrices and [ndarray](https://docs.rs/ndarray/latest/ndarray/).
//! - `num-complex`: provides the conversion between R's complex numbers and [num-complex](https://docs.rs/num-complex/latest/num_complex/).
//! - `serde`: provides the [Serde](https://serde.rs/) support.
//! - `graphics`: provides the functionality to control or implement graphics devices.

#![doc(
    html_logo_url = "https://raw.githubusercontent.com/extendr/extendr/master/extendr-logo-256.png"
)]

pub mod error;
pub mod functions;
pub mod io;
pub mod iter;
pub mod lang_macros;
pub mod metadata;
pub mod ownership;
pub mod prelude;
pub mod rmacros;

#[cfg(feature = "serde")]
pub mod serializer;

#[cfg(feature = "serde")]
pub mod deserializer;

#[cfg(feature = "graphics")]
pub mod graphics;

pub mod robj;
pub mod scalar;
pub mod thread_safety;
pub mod wrapper;

pub mod na;

#[cfg(feature = "ndarray")]
pub mod robj_ndarray;

pub use std::convert::{TryFrom, TryInto};
pub use std::ops::Deref;
pub use std::ops::DerefMut;

pub use robj::Robj;

//////////////////////////////////////////////////
// Note these pub use statements are deprecated
//
// `use extendr_api::prelude::*;`
//
// instead.

pub use error::*;
pub use functions::*;
pub use lang_macros::*;
pub use na::*;
pub use rmacros::*;
pub use robj::*;
pub use thread_safety::{
    catch_r_error, handle_panic, single_threaded, this_thread_id, throw_r_error,
};
pub use wrapper::*;

#[cfg(feature = "ndarray")]
pub use robj_ndarray::*;

pub use extendr_macros::*;

use scalar::Rbool;

//////////////////////////////////////////////////

/// TRUE value eg. `r!(TRUE)`
pub const TRUE: Rbool = Rbool::true_value();

/// FALSE value eg. `r!(FALSE)`
pub const FALSE: Rbool = Rbool::false_value();

/// NULL value eg. `r!(NULL)`
pub const NULL: () = ();

/// NA value for integers eg. `r!(NA_INTEGER)`
pub const NA_INTEGER: Option<i32> = None;

/// NA value for real values eg. `r!(NA_REAL)`
pub const NA_REAL: Option<f64> = None;

/// NA value for strings. `r!(NA_STRING)`
pub const NA_STRING: Option<&str> = None;

/// NA value for logical. `r!(NA_LOGICAL)`
pub const NA_LOGICAL: Rbool = Rbool::na_value();

#[doc(hidden)]
pub use std::collections::HashMap;

#[doc(hidden)]
pub use libR_sys::DllInfo;

#[doc(hidden)]
pub use libR_sys::SEXP;

#[doc(hidden)]
use libR_sys::*;

#[doc(hidden)]
use std::ffi::CString;

pub use metadata::Metadata;

#[doc(hidden)]
pub struct CallMethod {
    pub call_symbol: std::ffi::CString,
    pub func_ptr: *const u8,
    pub num_args: i32,
}

unsafe fn make_method_def(
    cstrings: &mut Vec<std::ffi::CString>,
    rmethods: &mut Vec<libR_sys::R_CallMethodDef>,
    func: &metadata::Func,
    wrapped_name: &str,
) {
    cstrings.push(std::ffi::CString::new(wrapped_name).unwrap());
    rmethods.push(libR_sys::R_CallMethodDef {
        name: cstrings.last().unwrap().as_ptr(),
        fun: Some(std::mem::transmute(func.func_ptr)),
        numArgs: func.args.len() as i32,
    });
}

// Internal function used to implement the .Call interface.
// This is called from the code generated by the #[extendr] attribute.
#[doc(hidden)]
pub unsafe fn register_call_methods(info: *mut libR_sys::DllInfo, metadata: Metadata) {
    let mut rmethods = Vec::new();
    let mut cstrings = Vec::new();
    for func in metadata.functions {
        let wrapped_name = format!("wrap__{}", func.mod_name);
        make_method_def(&mut cstrings, &mut rmethods, &func, wrapped_name.as_str());
    }

    for imp in metadata.impls {
        for func in imp.methods {
            let wrapped_name = format!("wrap__{}__{}", imp.name, func.mod_name);
            make_method_def(&mut cstrings, &mut rmethods, &func, wrapped_name.as_str());
        }
    }

    rmethods.push(libR_sys::R_CallMethodDef {
        name: std::ptr::null(),
        fun: None,
        numArgs: 0,
    });

    libR_sys::R_registerRoutines(
        info,
        std::ptr::null(),
        rmethods.as_ptr(),
        std::ptr::null(),
        std::ptr::null(),
    );

    // This seems to allow both symbols and strings,
    libR_sys::R_useDynamicSymbols(info, 0);
    libR_sys::R_forceSymbols(info, 0);
}

/// Type of R objects used by [Robj::rtype].
#[derive(Debug, PartialEq)]
pub enum Rtype {
    Null,        // NILSXP
    Symbol,      // SYMSXP
    Pairlist,    // LISTSXP
    Function,    // CLOSXP
    Environment, // ENVSXP
    Promise,     // PROMSXP
    Language,    // LANGSXP
    Special,     // SPECIALSXP
    Builtin,     // BUILTINSXP
    Rstr,        // CHARSXP
    Logicals,    // LGLSXP
    Integers,    // INTSXP
    Doubles,     // REALSXP
    Complexes,   // CPLXSXP
    Strings,     // STRSXP
    Dot,         // DOTSXP
    Any,         // ANYSXP
    List,        // VECSXP
    Expressions, // EXPRSXP
    Bytecode,    // BCODESXP
    ExternalPtr, // EXTPTRSXP
    WeakRef,     // WEAKREFSXP
    Raw,         // RAWSXP
    S4,          // S4SXP
    Unknown,
}

/// Enum use to unpack R objects into their specialist wrappers.
// Todo: convert all Robj types to wrappers.
// Note: this only works if the wrappers are all just SEXPs.
#[derive(Debug, PartialEq)]
pub enum Rany<'a> {
    Null(&'a Robj),               // NILSXP
    Symbol(&'a Symbol),           // SYMSXP
    Pairlist(&'a Pairlist),       // LISTSXP
    Function(&'a Function),       // CLOSXP
    Environment(&'a Environment), // ENVSXP
    Promise(&'a Promise),         // PROMSXP
    Language(&'a Language),       // LANGSXP
    Special(&'a Primitive),       // SPECIALSXP
    Builtin(&'a Primitive),       // BUILTINSXP
    Rstr(&'a Rstr),               // CHARSXP
    Logicals(&'a Logicals),       // LGLSXP
    Integers(&'a Integers),       // INTSXP
    Doubles(&'a Doubles),         // REALSXP
    Complexes(&'a Robj),          // CPLXSXP
    Strings(&'a Strings),         // STRSXP
    Dot(&'a Robj),                // DOTSXP
    Any(&'a Robj),                // ANYSXP
    List(&'a List),               // VECSXP
    Expressions(&'a Expressions), // EXPRSXP
    Bytecode(&'a Robj),           // BCODESXP
    ExternalPtr(&'a Robj),        // EXTPTRSXP
    WeakRef(&'a Robj),            // WEAKREFSXP
    Raw(&'a Raw),                 // RAWSXP
    S4(&'a S4),                   // S4SXP
    Unknown(&'a Robj),
}

/// Convert extendr's Rtype to R's SEXPTYPE.
/// Panics if the type is Unknown.
pub fn rtype_to_sxp(rtype: Rtype) -> i32 {
    use Rtype::*;
    (match rtype {
        Null => NILSXP,
        Symbol => SYMSXP,
        Pairlist => LISTSXP,
        Function => CLOSXP,
        Environment => ENVSXP,
        Promise => PROMSXP,
        Language => LANGSXP,
        Special => SPECIALSXP,
        Builtin => BUILTINSXP,
        Rstr => CHARSXP,
        Logicals => LGLSXP,
        Integers => INTSXP,
        Doubles => REALSXP,
        Complexes => CPLXSXP,
        Strings => STRSXP,
        Dot => DOTSXP,
        Any => ANYSXP,
        List => VECSXP,
        Expressions => EXPRSXP,
        Bytecode => BCODESXP,
        ExternalPtr => EXTPTRSXP,
        WeakRef => WEAKREFSXP,
        Raw => RAWSXP,
        S4 => S4SXP,
        Unknown => panic!("attempt to use Unknown Rtype"),
    }) as i32
}

/// Convert R's SEXPTYPE to extendr's Rtype.
pub fn sxp_to_rtype(sxptype: i32) -> Rtype {
    use Rtype::*;
    match sxptype as u32 {
        NILSXP => Null,
        SYMSXP => Symbol,
        LISTSXP => Pairlist,
        CLOSXP => Function,
        ENVSXP => Environment,
        PROMSXP => Promise,
        LANGSXP => Language,
        SPECIALSXP => Special,
        BUILTINSXP => Builtin,
        CHARSXP => Rstr,
        LGLSXP => Logicals,
        INTSXP => Integers,
        REALSXP => Doubles,
        CPLXSXP => Complexes,
        STRSXP => Strings,
        DOTSXP => Dot,
        ANYSXP => Any,
        VECSXP => List,
        EXPRSXP => Expressions,
        BCODESXP => Bytecode,
        EXTPTRSXP => ExternalPtr,
        WEAKREFSXP => WeakRef,
        RAWSXP => Raw,
        S4SXP => S4,
        _ => Unknown,
    }
}

#[doc(hidden)]
pub fn print_r_output<T: Into<Vec<u8>>>(s: T) {
    let cs = CString::new(s).expect("NulError");
    unsafe {
        Rprintf(cs.as_ptr());
    }
}

#[doc(hidden)]
pub fn print_r_error<T: Into<Vec<u8>>>(s: T) {
    let cs = CString::new(s).expect("NulError");
    unsafe {
        REprintf(cs.as_ptr());
    }
}

#[cfg(test)]
mod tests {
    use super::prelude::*;
    use crate as extendr_api;

    use extendr_macros::extendr;
    use extendr_macros::extendr_module;
    use extendr_macros::pairlist;

    #[extendr]
    pub fn inttypes(a: i8, b: u8, c: i16, d: u16, e: i32, f: u32, g: i64, h: u64) {
        assert_eq!(a, 1);
        assert_eq!(b, 2);
        assert_eq!(c, 3);
        assert_eq!(d, 4);
        assert_eq!(e, 5);
        assert_eq!(f, 6);
        assert_eq!(g, 7);
        assert_eq!(h, 8);
    }

    #[extendr]
    pub fn floattypes(a: f32, b: f64) {
        assert_eq!(a, 1.);
        assert_eq!(b, 2.);
    }

    #[extendr]
    pub fn strtypes(a: &str, b: String) {
        assert_eq!(a, "abc");
        assert_eq!(b, "def");
    }

    #[extendr]
    pub fn vectortypes(a: Vec<i32>, b: Vec<f64>) {
        assert_eq!(a, [1, 2, 3]);
        assert_eq!(b, [4., 5., 6.]);
    }

    #[extendr]
    pub fn robjtype(a: Robj) {
        assert_eq!(a, Robj::from(1))
    }

    #[extendr]
    pub fn return_u8() -> u8 {
        123
    }

    #[extendr]
    pub fn return_u16() -> u16 {
        123
    }

    #[extendr]
    pub fn return_u32() -> u32 {
        123
    }

    #[extendr]
    pub fn return_u64() -> u64 {
        123
    }

    #[extendr]
    pub fn return_i8() -> i8 {
        123
    }

    #[extendr]
    pub fn return_i16() -> i16 {
        123
    }

    #[extendr]
    pub fn return_i32() -> i32 {
        123
    }

    #[extendr]
    pub fn return_i64() -> i64 {
        123
    }

    #[extendr]
    pub fn return_f32() -> f32 {
        123.
    }

    #[extendr]
    pub fn return_f64() -> f64 {
        123.
    }

    #[extendr]
    pub fn f64_slice(x: &[f64]) -> &[f64] {
        x
    }

    #[extendr]
    pub fn i32_slice(x: &[i32]) -> &[i32] {
        x
    }

    #[extendr]
    pub fn bool_slice(x: &[Rbool]) -> &[Rbool] {
        x
    }

    #[extendr]
    pub fn f64_iter(x: Doubles) -> Doubles {
        x
    }

    #[extendr]
    pub fn i32_iter(x: Integers) -> Integers {
        x
    }

    // #[extendr]
    // pub fn bool_iter(x: Logicals) -> Logicals {
    //     x
    // }

    #[extendr]
    pub fn symbol(x: Symbol) -> Symbol {
        x
    }

    #[extendr]
    pub fn matrix(x: RMatrix<f64>) -> RMatrix<f64> {
        x
    }

    struct Person {
        pub name: String,
    }

    #[extendr]
    /// impl comment.
    impl Person {
        fn new() -> Self {
            Self {
                name: "".to_string(),
            }
        }

        fn set_name(&mut self, name: &str) {
            self.name = name.to_string();
        }

        fn name(&self) -> &str {
            self.name.as_str()
        }
    }

    // see metadata_test for the following comments.

    /// comment #1
    /// comment #2
    /**
        comment #3
        comment #4
    **/
    #[extendr]
    /// aux_func doc comment.
    fn aux_func(_person: &Person) {}

    // Macro to generate exports
    extendr_module! {
        mod my_module;
        fn aux_func;
        impl Person;
    }

    #[test]
    fn export_test() {
        test! {
            use super::*;
            // Call the exported functions through their generated C wrappers.
            unsafe {
                wrap__inttypes(
                    Robj::from(1).get(),
                    Robj::from(2).get(),
                    Robj::from(3).get(),
                    Robj::from(4).get(),
                    Robj::from(5).get(),
                    Robj::from(6).get(),
                    Robj::from(7).get(),
                    Robj::from(8).get(),
                );
                wrap__inttypes(
                    Robj::from(1.).get(),
                    Robj::from(2.).get(),
                    Robj::from(3.).get(),
                    Robj::from(4.).get(),
                    Robj::from(5.).get(),
                    Robj::from(6.).get(),
                    Robj::from(7.).get(),
                    Robj::from(8.).get(),
                );
                wrap__floattypes(Robj::from(1.).get(), Robj::from(2.).get());
                wrap__floattypes(Robj::from(1).get(), Robj::from(2).get());
                wrap__strtypes(Robj::from("abc").get(), Robj::from("def").get());
                wrap__vectortypes(
                    Robj::from(&[1, 2, 3] as &[i32]).get(),
                    Robj::from(&[4., 5., 6.] as &[f64]).get(),
                );
                wrap__robjtype(Robj::from(1).get());

                // General integer types.
                assert_eq!(Robj::from_sexp(wrap__return_u8()), Robj::from(123_u8));
                assert_eq!(Robj::from_sexp(wrap__return_u16()), Robj::from(123));
                assert_eq!(Robj::from_sexp(wrap__return_u32()), Robj::from(123.));
                assert_eq!(Robj::from_sexp(wrap__return_u64()), Robj::from(123.));
                assert_eq!(Robj::from_sexp(wrap__return_i8()), Robj::from(123));
                assert_eq!(Robj::from_sexp(wrap__return_i16()), Robj::from(123));
                assert_eq!(Robj::from_sexp(wrap__return_i32()), Robj::from(123));
                assert_eq!(Robj::from_sexp(wrap__return_i64()), Robj::from(123.));

                // Floating point types.
                assert_eq!(Robj::from_sexp(wrap__return_f32()), Robj::from(123.));
                assert_eq!(Robj::from_sexp(wrap__return_f64()), Robj::from(123.));
            }
        }
    }

    #[test]
    fn class_wrapper_test() {
        test! {
            let mut person = Person::new();
            person.set_name("fred");
            let robj = r!(person);
            assert_eq!(robj.check_external_ptr("Person"), true);
            let person2 = <&Person>::from_robj(&robj).unwrap();
            assert_eq!(person2.name(), "fred");
        }
    }

    #[test]
    fn slice_test() {
        test! {
            unsafe {
                // #[extendr]
                // pub fn f64_slice(x: &[f64]) -> &[f64] { x }

                let robj = r!([1., 2., 3.]);
                assert_eq!(Robj::from_sexp(wrap__f64_slice(robj.get())), robj);

                // #[extendr]
                // pub fn i32_slice(x: &[i32]) -> &[i32] { x }

                let robj = r!([1, 2, 3]);
                assert_eq!(Robj::from_sexp(wrap__i32_slice(robj.get())), robj);

                // #[extendr]
                // pub fn bool_slice(x: &[Rbool]) -> &[Rbool] { x }

                let robj = r!([TRUE, FALSE, TRUE]);
                assert_eq!(Robj::from_sexp(wrap__bool_slice(robj.get())), robj);

                // #[extendr]
                // pub fn f64_iter(x: Doubles) -> Doubles { x }

                let robj = r!([1., 2., 3.]);
                assert_eq!(Robj::from_sexp(wrap__f64_iter(robj.get())), robj);

                // #[extendr]
                // pub fn i32_iter(x: Integers) -> Integers { x }

                let robj = r!([1, 2, 3]);
                assert_eq!(Robj::from_sexp(wrap__i32_iter(robj.get())), robj);

                // #[extendr]
                // pub fn bool_iter(x: Logicals) -> Logicals { x }

                // TODO: reinstate this test.
                // let robj = r!([TRUE, FALSE, TRUE]);
                // assert_eq!(Robj::from_sexp(wrap__bool_iter(robj.get())), robj);

                // #[extendr]
                // pub fn symbol(x: Symbol) -> Symbol { x }

                let robj = sym!(fred);
                assert_eq!(Robj::from_sexp(wrap__symbol(robj.get())), robj);

                // #[extendr]
                // pub fn matrix(x: Matrix<&[f64]>) -> Matrix<&[f64]> { x }

                let m = RMatrix::new_matrix(1, 2, |r, c| if r == c {1.0} else {0.});
                let robj = r!(m);
                assert_eq!(Robj::from_sexp(wrap__matrix(robj.get())), robj);
            }
        }
    }

    #[test]
    fn r_output_test() {
        // R equivalent
        // > txt_con <- textConnection("test_con", open = "w")
        // > sink(txt_con)
        // > cat("Hello world")
        // > sink()
        // > close(txt_con)
        // > expect_equal(test_con, "Hello world")
        //

        test! {
            let txt_con = R!(r#"textConnection("test_con", open = "w")"#).unwrap();
            call!("sink", &txt_con).unwrap();
            rprintln!("Hello world");
            call!("sink").unwrap();
            call!("close", &txt_con).unwrap();
            let result = R!("test_con").unwrap();
            assert_eq!(result, r!("Hello world"));
        }
    }

    #[test]
    fn test_na_str() {
        assert_ne!(<&str>::na().as_ptr(), "NA".as_ptr());
        assert_eq!(<&str>::na(), "NA");
        assert_eq!("NA".is_na(), false);
        assert_eq!(<&str>::na().is_na(), true);
    }

    #[test]
    fn metadata_test() {
        test! {
            // Rust interface.
            let metadata = get_my_module_metadata();
            assert_eq!(metadata.functions[0].doc, " comment #1\n comment #2\n\n        comment #3\n        comment #4\n    *\n aux_func doc comment.");
            assert_eq!(metadata.functions[0].rust_name, "aux_func");
            assert_eq!(metadata.functions[0].mod_name, "aux_func");
            assert_eq!(metadata.functions[0].r_name, "aux_func");
            assert_eq!(metadata.functions[0].args[0].name, "_person");
            assert_eq!(metadata.functions[1].rust_name, "get_my_module_metadata");
            assert_eq!(metadata.impls[0].name, "Person");
            assert_eq!(metadata.impls[0].methods.len(), 3);

            // R interface
            let robj = Robj::from_sexp(wrap__get_my_module_metadata());
            let functions = robj.dollar("functions").unwrap();
            let impls = robj.dollar("impls").unwrap();
            assert_eq!(functions.len(), 3);
            assert_eq!(impls.len(), 1);
        }
    }

    #[test]
    fn pairlist_macro_works() {
        test! {
            assert_eq!(pairlist!(1, 2, 3), Pairlist::from_pairs(&[("", 1), ("", 2), ("", 3)]));
            assert_eq!(pairlist!(a=1, 2, 3), Pairlist::from_pairs(&[("a", 1), ("", 2), ("", 3)]));
            assert_eq!(pairlist!(1, b=2, 3), Pairlist::from_pairs(&[("", 1), ("b", 2), ("", 3)]));
            assert_eq!(pairlist!(a=1, b=2, c=3), Pairlist::from_pairs(&[("a", 1), ("b", 2), ("c", 3)]));
            assert_eq!(pairlist!(a=NULL), Pairlist::from_pairs(&[("a", ())]));
            assert_eq!(pairlist!(), Pairlist::from(()));
        }
    }

    #[test]
    fn big_r_macro_works() {
        test! {
            assert_eq!(R!("1")?, r!(1.0));
            assert_eq!(R!(r"1")?, r!(1.0));
            assert_eq!(R!(r"
                x <- 1
                x
            ")?, r!(1.0));
            assert_eq!(R!(r"
                x <- {{ 1.0 }}
                x
            ")?, r!(1.0));
            assert_eq!(R!(r"
                x <- {{ (0..4).collect_robj() }}
                x
            ")?, r!([0, 1, 2, 3]));
            assert_eq!(R!(r#"
                x <- "hello"
                x
            "#)?, r!("hello"));
            assert_eq!(Rraw!(r"
                x <- {{ 1 }}
                x
            ")?, r!(1.0));
        }
    }
}