====== Character functions ======

ACSUtils implements functions from the C programming language's [[http://www.cplusplus.com/reference/cctype/|ctype.h]]. Only ASCII characters are supported.


===== Character classification =====

  * ''bool isalnum(int c)'' -- returns true if the character is a letter or a digit.
  * ''bool isalpha(int c)'' -- returns true if the character is a letter.
  * ''bool isblank(int c)'' -- returns true if the character is blank.
  * ''bool iscntrl(int c)'' -- returns true if the character is a control character.
  * ''bool isdigit(int c)'' -- returns true if the character is a digit.
  * ''bool isgraph(int c)'' -- returns true if the character has a graphical representation.
  * ''bool islower(int c)'' -- returns true if the character is lowercase.
  * ''bool isprint(int c)'' -- returns true if the character is printable. Inverse of ''iscntrl()''.
  * ''bool isprint(int c)'' -- returns true if the character is a punctuation character.
  * ''bool isspace(int c)'' -- returns true if the character whitespace.
  * ''bool isupper(int c)'' -- returns true if the character is uppercase.
  * ''bool isxdigit(int c)'' -- returns true if the character is a hexadecimal digit (''0123456789abcdef'').

ACSUtils additions:

  * ''bool isascii(int c)'' -- returns true if the character is an ASCII character.

Character classification functions return false for all non-ASCII characters.


===== Case conversion =====

If the character is not a letter, these functions return the original character:

  * ''int tolower(int c)'' -- returns the lowercase version of the character.
  * ''int toupper(int c)'' -- returns the uppercase version of the character.

Non-ASCII characters are always returned without conversion.


===== String versions of the above functions =====

These functions return true if all characters in the string match a character classification function:

  * ''bool StrIsAscii(str s)'' -- ''isascii''
  * ''bool StrIsAlnum(str s)'' -- ''isalnum''
  * ''bool StrIsAlpha(str s)'' -- ''isalpha''
  * ''bool StrIsBlank(str s)'' -- ''isblank''
  * ''bool StrIsCntrl(str s)'' -- ''iscntrl''
  * ''bool StrIsDigit(str s)'' -- ''isdigit''
  * ''bool StrIsGraph(str s)'' -- ''isgraph''
  * ''bool StrIsLower(str s)'' -- ''islower''
  * ''bool StrIsPrint(str s)'' -- ''isprint''
  * ''bool StrIsSpace(str s)'' -- ''isspace''
  * ''bool StrIsUpper(str s)'' -- ''isupper''
  * ''bool StrIsXDigit(str s)'' -- ''isxdigit''

These functions make all characters in the string lowercase or uppercase:

  * ''str StrToLower(str s)'' -- returns the string with all characters converted to lowercase.
  * ''str StrToUpper(str s)'' -- returns the string with all characters converted to uppercase.