#lang scribble/doc @(require (file "base.ss")) @title[#:tag "number"]{Number utilities} @defmodule[(planet untyped/unlib/number)]{ Useful number utilities. @defproc[(number+false? [item any]) boolean?]{ Returns @scheme[#t] if @scheme[item] is a number or #scheme[#f].} @defproc[(integer+false? [item any]) boolean?]{ Returns @scheme[#t] if @scheme[item] is an integer or #scheme[#f].} @defproc[(natural? [item any]) boolean?]{ Returns @scheme[#t] if @scheme[item] is an natural number (>= 0).} @defproc[(natural+false? [item any]) boolean?]{ Returns @scheme[#t] if @scheme[item] is an natural number (>= 0) or @scheme[#f].} @defproc[(number+false->symbol+false [num (U number? #f)]) (U symbol? #f)]{ A version of @scheme[number->symbol] that accepts and passes through @scheme[#f].} @defproc[(symbol+false->number+false [sym (U symbol? #f)]) (U number? #f)]{ A version of @scheme[symbol->number] that accepts and passes through @scheme[#f].} @defproc[(number+false->string+false [num (U number? #f)]) (U string? #f)]{ A version of @scheme[number->string] that accepts and passes through @scheme[#f].} @defproc[(string+false->number+false [str (U string? #f)]) (U number? #f)]{ A version of @scheme[string->number] that accepts and passes through @scheme[#f].} } @;{end defmodule}