char-alphabetic?, char-numeric?, etc - test character properties

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LIBRARY

(import (rnrs))                     ;R6RS
(import (rnrs unicode))             ;R6RS
(import (scheme r5rs))              ;R7RS
(import (scheme char))              ;R7RS

SYNOPSIS

(char-alphabetic? char)
(char-numeric? char)
(char-whitespace? char)
(char-upper-case? char)
(char-lower-case? char)
(char-title-case? char)             ;R6RS

DESCRIPTION

A character is alphabetic if it has the Unicode "Alphabetic" property. A character is numeric if it has the Unicode "Numeric" property. A character is whitespace if has the Unicode "White_Space" property. A character is upper case if it has the Unicode "Uppercase" property, lower case if it has the "Lowercase" property, and title case if it is in the Lt general category.

R7RS notes that char-numeric? tests for "Numeric_Type=Decimal". Either way, it checks if the character is a decimal number.

RETURN VALUES

EXAMPLES

(char-alphabetic? #\a)      =>  #t
(char-numeric? #\1)         =>  #t
(char-whitespace? #\space)  =>  #t

;; The following are not required to be supported in R7RS.
(char-numeric? #\x096A)     =>  #t
(char-whitespace? #\x00A0)  =>  #t
(char-upper-case? #\Σ)      =>  #t
(char-lower-case? #\σ)      =>  #t

COMPATIBILITY

R5RS and earlier reports mention the proper semantics for ASCII, but implementations are free to use e.g. EBCDIC instead.

ERRORS

&assertion (R6RS)

The wrong number of arguments was passed or an argument was outside its domain.

R7RS

The assertions described above are errors. Implementations may signal an error, extend the procedure's domain of definition to include such arguments, or fail catastrophically.

SEE ALSO

STANDARDS

AUTHORS