Assertion factories of package 'typed'

These functions are assertion factories, they produce assertions, which take an object, check conditions, and returns the input, usually unmodified (never modified with the functions documented on this page).

Additional conditions can be provided :

• If they are named, the name should be the name of a function to use on our object, and the value should be the expected value.

• If they are unnamed, they should be formulas, the right hand side should be a condition, using value or . as a placeholder for the latter, and the optional lhs an error message.

Any is the most general assertion factory, it doesn't check anything unless provided additional conditions through .... Others use the base is.<type> function if available, or check that the object is of the relevant type with typeof for atomic types, or check that the class of the checked value contains the relevant class.

See advanced examples at the bottom, including uses of Symbol() and Dots().

Usage

Any(length = NULL, ...)

Logical(length = NULL, null_ok = FALSE, ...)

Integer(length = NULL, null_ok = FALSE, ...)

Double(length = NULL, null_ok = FALSE, ...)

Character(length = NULL, null_ok = FALSE, ...)

Raw(length = NULL, null_ok = FALSE, ...)

List(length = NULL, each, data_frame_ok, null_ok = FALSE, ...)

Null(...)

Closure(null_ok = FALSE, ...)

Special(null_ok = FALSE, ...)

Builtin(null_ok = FALSE, ...)

Environment(null_ok = FALSE, ...)

Symbol(null_ok = FALSE, ...)

Pairlist(length = NULL, each, null_ok = TRUE, ...)

Language(null_ok = FALSE, ...)

Expression(length = NULL, null_ok = FALSE, ...)

Function(null_ok = FALSE, ...)

Factor(length = NULL, levels, null_ok = FALSE, ...)

Matrix(nrow, ncol, null_ok = FALSE, ...)

Array(dim, null_ok = FALSE, ...)

Data.frame(nrow, ncol, each, null_ok = FALSE, ...)

Date(length = NULL, null_ok = FALSE, ...)

Time(length = NULL, null_ok = FALSE, ...)

Dots(length = NULL, each, ...)

Logical(length = NULL, null_ok = FALSE, ...)

Integer(length = NULL, null_ok = FALSE, ...)

Double(length = NULL, null_ok = FALSE, ...)

Character(length = NULL, null_ok = FALSE, ...)

Raw(length = NULL, null_ok = FALSE, ...)

List(length = NULL, each, data_frame_ok = TRUE, null_ok = FALSE, ...)

Null(...)

Closure(null_ok = FALSE, ...)

Special(null_ok = FALSE, ...)

Builtin(null_ok = FALSE, ...)

Environment(null_ok = FALSE, ...)

Symbol(null_ok = FALSE, ...)

Pairlist(length = NULL, each, null_ok = TRUE, ...)

Language(null_ok = FALSE, ...)

Expression(length = NULL, null_ok = FALSE, ...)

Function(null_ok = FALSE, ...)

Factor(length = NULL, levels, null_ok = FALSE, ...)

Data.frame(nrow, ncol, each, null_ok = FALSE, ...)

Matrix(nrow, ncol, null_ok = FALSE, ...)

Array(dim, null_ok = FALSE, ...)

Date(length = NULL, null_ok = FALSE, ...)

Time(length = NULL, null_ok = FALSE, ...)

Dots(length = NULL, each, ...)

Arguments

length

length of the object

...

additional conditions, see details.

null_ok

whether NULL values should be accepted, and not subjected to any further check.

each

assertion that every item must satisfy

data_frame_ok

whether data frames are to be considered as lists

levels

factor levels

nrow

number of rows

ncol

number of columns

dim

dimensions

Value

A function, and more specifically, an assertion as defined above.

Examples

if (FALSE) { # \dontrun{
# fails
Integer() ? x <- 1
# equivalent to
declare("x", Integer(), value = 1)

Integer(2) ? x <- 1L

# we can use additional conditions in `...`
Integer(anyNA = FALSE) ? x <- c(1L, NA, 1L)
Integer(anyDuplicated = 0L) ? x <- c(1L, NA, 1L)
} # }

Integer(2) ? x <- 11:12

if (FALSE) { # \dontrun{
# We can also use it directly to test assertions
Integer() ? x <- 1
# equivalent to
declare("x", Integer(), value = 1)

Integer(2) ? x <- 1L
} # }

if (FALSE) { # \dontrun{
# I we want to restrict the quoted expression rather than the value of an
# argument, we can use `?~` :
identity_sym_only <- ? function (x= ?~ Symbol()) {
  x
}

a <- 1
identity_sym_only(a)
identity_sym_only(a + a)

identity_sym_only
} # }

if (FALSE) { # \dontrun{
integer_list <- ? function (...= ? Integer()) {
  list(...)
}

integer_list(1L, 2L, "a")

integer_pair <- ? function (...= ? Dots(2, each = Integer())) {
  list(...)
}

integer_pair(1L, 2L, 3L)
integer_pair(1L, "a", "a")

x <- 1
y <- 2
symbol_list1 <- ? function (...= ? Dots(2, Symbol())) {
  list(...)
}
symbol_list1(quote(x), quote(y))
symbol_list1(x, y)

symbol_list2 <- ? function (...= ?~ Dots(2, Symbol())) {
  list(...)
}
symbol_list2(x, x + y)
symbol_list2(x, y)
} # }