scalar-checkers {valaddin}

Scalar checkers

Description

These functions make check formulae of local scope based on the correspondingly named scalar type predicate from base R. For example, vld_scalar_logical creates check formulae (of local scope) for the predicate is.logical(.) && length(.) == 1. The function vld_singleton is based on the predicate length(.) == 1.

The functions vld_boolean, vld_number, vld_string are aliases for vld_scalar_logical, vld_scalar_numeric, vld_scalar_character, resp. (with appropriately modified error messages).

Usage

vld_boolean(...)

vld_number(...)

vld_scalar_atomic(...)

vld_scalar_character(...)

vld_scalar_complex(...)

vld_scalar_double(...)

vld_scalar_integer(...)

vld_scalar_list(...)

vld_scalar_logical(...)

vld_scalar_numeric(...)

vld_scalar_raw(...)

vld_scalar_vector(...)

vld_singleton(...)

vld_string(...)

Arguments

...

Check items, i.e., formulae that are one-sided or have a string as left-hand side (see Check Formulae of Local Scope in the documentation page firmly). These are the expressions to check.

Details

Each function vld_* is a function of class "check_maker", generated by localize.

Value

Check formula of local scope.

See Also

Corresponding predicates: is.atomic, is.character, is.complex, is.double, is.integer, is.list, is.logical, is.numeric, is.raw, is.vector

globalize recovers the underlying check formula of global scope.

The notions of “scope” and “check item” are explained in the Check Formulae section of firmly.

Other checkers: type-checkers, misc-checkers

Examples

## Not run: 

f <- function(x, y) "Pass"

# Impose a check on x: ensure it's boolean (i.e., a scalar logical vector)
f_firm <- firmly(f, vld_boolean(~x))
f_firm(TRUE, 0)           # [1] "Pass"
f_firm(c(TRUE, TRUE), 0)  # Error: "Not boolean: x"

# Use a custom error message
f_firm <- firmly(f, vld_boolean("x is not TRUE/FALSE/NA" ~ x))
f_firm(c(TRUE, TRUE), 0)  # Error: "x is not TRUE/FALSE/NA"

# To impose the same check on all arguments, apply globalize
f_firmer <- firmly(f, globalize(vld_boolean))
f_firmer(TRUE, FALSE)    # [1] "Pass"
f_firmer(TRUE, 0)        # Error: "Not boolean: `y`"
f_firmer(logical(0), 0)  # Errors: "Not boolean: `x`", "Not boolean: `y`"

## End(Not run)