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Compile C++20 code

Source: R/cpp_source.R
cpp_source.Rd

cpp11-style helpers to compile cppally code outside of a cppally-linked package context.

cpp_source() compiles and loads a single C++ file for use in R, either from an expression or a cpp file. This may include multiple C++ functions.

cpp_eval() evaluates a single C++ expression and returns the result. For example cpp_eval('get_threads()') will run the C++ function cppally::get_threads() and return the number of OMP threads currently set for use. For expressions no return result, the call is evaluated and returns NULL invisibly.

Usage

cpp_source(
  file,
  code = NULL,
  env = parent.frame(),
  clean = TRUE,
  quiet = TRUE,
  debug = FALSE,
  preserve_altrep = FALSE,
  cxx_std = Sys.getenv("CXX_STD", "CXX20"),
  dir = tempfile()
)

cpp_eval(
  code,
  env = curr_env(),
  clean = TRUE,
  quiet = TRUE,
  debug = FALSE,
  preserve_altrep = FALSE,
  simplify = TRUE,
  cxx_std = Sys.getenv("CXX_STD", "CXX20")
)

Arguments

file

C++ file.

code

For cpp_source() - If file is NULL then a string of C++ code to compile. This can include the contents of a cpp file which can contain multiple [[cppally::register]] tagged functions. For cpp_eval - This can be a character vector of single-line expressions.

env

Environment where R functions should be defined.

clean

Should files be cleaned up after sourcing? Default is TRUE.

quiet

Should compiler output be suppressed? Default is TRUE.

debug

Should C++ code be compiled in a debug build? Default is FALSE.

preserve_altrep

Should ALTREP vectors be preserved by avoiding materialisation where possible? Default is FALSE.

cxx_std

C++ standard to use. Should be >= C++20.

dir

Directory to store the source files. The default is a temporary directory via tempfile() which is removed when clean = TRUE.

simplify

Applies to cpp_eval. A list of results is returned unless length(code) == 1 and simplify = TRUE.

Value

cpp_source() invisibly compiles the C++ code and registers the [[cppally::register]] tagged functions to R.
cpp_eval() returns the results of the evaluated C++ expressions.

Examples


library(cppally)
library(bit64)
#> The assignment of character values to integer64 vectors and matrices with automatic coercion to integer64 will change to a more R consistent behaviour of coercing to character in future versions of bit64. If you wish you can update your code to the new behaviour by setting the option 'bit64.promoteInteger64ToCharacter' to TRUE.
#> 
#> Attaching package: ‘bit64’
#> The following object is masked from ‘package:utils’:
#> 
#>     hashtab
#> The following objects are masked from ‘package:base’:
#> 
#>     %in%, :, array, as.factor, as.ordered, colSums, factor, intersect,
#>     is.double, is.element, match, matrix, order, rank, rowSums,
#>     setdiff, setequal, table, union
# \donttest{
cpp_eval('print("hello world!")')
#> hello world!

# Default values of all cppally scalars
cpp_eval(c(
  'r_lgl()',
  'r_int()',
  'r_dbl()',
  'r_int64()',
  'r_str()',
  'r_raw()',
  'r_cplx()',
  'r_date()',
  'r_psxct()'
))
#> $res1
#> [1] FALSE
#> 
#> $res2
#> [1] 0
#> 
#> $res3
#> [1] 0
#> 
#> $res4
#> integer64
#> [1] 0
#> 
#> $res5
#> [1] ""
#> 
#> $res6
#> [1] 00
#> 
#> $res7
#> [1] 0+0i
#> 
#> $res8
#> [1] "1970-01-01"
#> 
#> $res9
#> [1] "1970-01-01 UTC"
#> 

cpp_source(code = '
  #include <cppally.hpp>
  using namespace cppally;

  [[cppally::register]]
  r_dbl add(r_dbl x, r_dbl y){
    return x + y;
  }
', debug = TRUE)
add(1, 2)
#> [1] 3
add(2, NA)
#> [1] NA

### ALTREP ###

# cppally also supports lazy ALTREP materialisation as an opt-in feature.
# To opt-in, set `preserve_altrep = TRUE`

cpp_source(
  code = '
  #include <cppally.hpp>
  using namespace cppally;

  [[cppally::register]]
  r_int last_altrep_unaware(r_vec<r_int> x){
    r_int out;
    r_size_t n = x.length();

    if (n > 0){
      out = x.get(n - 1);
    }
    return out;
  }
', debug = TRUE
)

cpp_source(
  code = '
  #include <cppally.hpp>
  using namespace cppally;

  [[cppally::register]]
  r_int last_altrep_aware(r_vec<r_int> x){
    r_int out;
    r_size_t n = x.length();

    if (n > 0){
      out = x.get(n - 1);
    }
    return out;
  }
', debug = TRUE,
  preserve_altrep = TRUE
)

library(bench)
mark(last_altrep_aware(1:10^5)) # No materialisation
#> # A tibble: 1 × 13
#>   expression      min median `itr/sec` mem_alloc `gc/sec` n_itr  n_gc total_time
#>   <bch:expr>   <bch:> <bch:>     <dbl> <bch:byt>    <dbl> <int> <dbl>   <bch:tm>
#> 1 last_altrep… 3.74µs 4.47µs   202621.    3.18KB        0 10000     0     49.4ms
#> # ℹ 4 more variables: result <list>, memory <list>, time <list>, gc <list>
mark(last_altrep_unaware(1:10^5)) # Materialises full vector
#> # A tibble: 1 × 13
#>   expression      min median `itr/sec` mem_alloc `gc/sec` n_itr  n_gc total_time
#>   <bch:expr>   <bch:> <bch:>     <dbl> <bch:byt>    <dbl> <int> <dbl>   <bch:tm>
#> 1 last_altrep… 36.3µs 37.8µs    23030.     391KB     183.  4160    33      181ms
#> # ℹ 4 more variables: result <list>, memory <list>, time <list>, gc <list>

# }