type2.md
In vctrs: Vector Helpers

base coercions are symmetric and unchanging

Code
  mat
Output
            logical   integer   double   character   raw   list  
  logical   "logical" "integer" "double" NA          NA    NA    
  integer   "integer" "integer" "double" NA          NA    NA    
  double    "double"  "double"  "double" NA          NA    NA    
  character NA        NA        NA       "character" NA    NA    
  raw       NA        NA        NA       NA          "raw" NA    
  list      NA        NA        NA       NA          NA    "list"

vec_ptype2() data frame methods builds argument tags

Code
  vec_ptype2("foo", 10)
Condition
  Error:
  ! Can't combine `"foo"` <character> and `10` <double>.

Code
  df1 <- tibble(x = tibble(y = tibble(z = 1)))
  df2 <- tibble(x = tibble(y = tibble(z = "a")))
  vec_ptype2(df1, df2)
Condition
  Error:
  ! Can't combine `df1$x$y$z` <double> and `df2$x$y$z` <character>.

can override scalar vector error message for base scalar types

Code
  (expect_error(vec_ptype2(NULL, quote(x), y_arg = "foo"), class = "vctrs_error_scalar_type")
  )
Output
  <error/vctrs_error_scalar_type>
  Error:
  ! `foo` must be a vector, not a symbol.
Code
  (expect_error(vec_ptype2(quote(x), NULL, x_arg = "foo"), class = "vctrs_error_scalar_type")
  )
Output
  <error/vctrs_error_scalar_type>
  Error:
  ! `foo` must be a vector, not a symbol.

can override scalar vector error message for S3 types

Code
  (expect_error(vec_ptype2(NULL, foobar(), y_arg = "foo"), class = "vctrs_error_scalar_type")
  )
Output
  <error/vctrs_error_scalar_type>
  Error:
  ! `foo` must be a vector, not a <vctrs_foobar> object.
Code
  (expect_error(vec_ptype2(foobar(), NULL, x_arg = "foo"), class = "vctrs_error_scalar_type")
  )
Output
  <error/vctrs_error_scalar_type>
  Error:
  ! `foo` must be a vector, not a <vctrs_foobar> object.

ptype2 and cast errors when same class fallback is impossible are informative

Code
  (expect_error(vec_cast(foobar(1, bar = TRUE), foobar(2, baz = TRUE)), class = "vctrs_error_incompatible_type")
  )
Output
  <error/vctrs_error_cast>
  Error:
  ! Can't convert `foobar(1, bar = TRUE)` <vctrs_foobar> to <vctrs_foobar>.
Code
  (expect_error(vec_ptype2(foobar(1, bar = TRUE), foobar(2, baz = TRUE)), class = "vctrs_error_incompatible_type")
  )
Output
  <error/vctrs_error_ptype2>
  Error:
  ! Can't combine `foobar(1, bar = TRUE)` <vctrs_foobar> and `foobar(2, baz = TRUE)` <vctrs_foobar>.
  x Some attributes are incompatible.
  i The author of the class should implement vctrs methods.
  i See <https://vctrs.r-lib.org/reference/faq-error-incompatible-attributes.html>.

Incompatible attributes bullets are not show when methods are implemented

Code
  with_foobar_cast <- (function(expr) {
    with_methods(vec_cast.vctrs_foobar = function(...) NULL,
    vec_cast.vctrs_foobar.vctrs_foobar = function(x, to, ...) vec_default_cast(x,
      to, ...), expr)
  })
  with_foobar_ptype2 <- (function(expr) {
    with_methods(vec_ptype2.vctrs_foobar = function(...) NULL,
    vec_ptype2.vctrs_foobar.vctrs_foobar = function(x, y, ...) vec_default_ptype2(
      x, y, ...), expr)
  })
  (expect_error(with_foobar_cast(vec_cast(foobar(1, bar = TRUE), foobar(2, baz = TRUE))),
  class = "vctrs_error_incompatible_type"))
Output
  <error/vctrs_error_cast>
  Error:
  ! Can't convert `foobar(1, bar = TRUE)` <vctrs_foobar> to <vctrs_foobar>.
Code
  (expect_error(with_foobar_ptype2(vec_ptype2(foobar(1, bar = TRUE), foobar(2,
    baz = TRUE))), class = "vctrs_error_incompatible_type"))
Output
  <error/vctrs_error_ptype2>
  Error:
  ! Can't combine `foobar(1, bar = TRUE)` <vctrs_foobar> and `foobar(2, baz = TRUE)` <vctrs_foobar>.