On this page:
number+ false?
integer+ false?
natural?
natural+ false?
number+ false->symbol+ false
symbol+ false->number+ false
number+ false->string+ false
string+ false->number+ false
Version: 4.1.4.1

18 Number utilities

 (require (planet untyped/unlib/number))

Useful number utilities.

(number+false? item)  boolean?
  item : any

Returns #t if item is a number or #scheme[#f].

(integer+false? item)  boolean?
  item : any

Returns #t if item is an integer or #scheme[#f].

(natural? item)  boolean?
  item : any

Returns #t if item is an natural number (>= 0).

(natural+false? item)  boolean?
  item : any

Returns #t if item is an natural number (>= 0) or #f.

(number+false->symbol+false num)  (U symbol? #f)
  num : (U number? #f)

A version of number->symbol that accepts and passes through #f.

(symbol+false->number+false sym)  (U number? #f)
  sym : (U symbol? #f)

A version of symbol->number that accepts and passes through #f.

(number+false->string+false num)  (U string? #f)
  num : (U number? #f)

A version of number->string that accepts and passes through #f.

(string+false->number+false str)  (U number? #f)
  str : (U string? #f)

A version of string->number that accepts and passes through #f.