const type: char

The type char describes Unicode characters encoded with UTF-32. A char can also contain values, which are not Unicode, like EOF.

const char: EOF

Character representing end-of-file. EOF is not an Unicode character.

const char: (attr char) . value

Default value of char (' ').

const char: (attr char) . first

Minimum value of char.

const char: (attr char) . last

Maximum value of an Unicode character.

const func boolean: (in char: ch1) = (in char: ch2)

Check if two characters are equal.

Returns:

TRUE if both characters are equal, FALSE otherwise.

const func boolean: (in char: ch1) <> (in char: ch2)

Check if two characters are not equal.

Returns:

FALSE if both characters are equal, TRUE otherwise.

const func boolean: (in char: ch1) < (in char: ch2)

Check if ch1 is less than ch2.

Returns:

TRUE if ch1 is less than than ch2, FALSE otherwise.

const func boolean: (in char: ch1) > (in char: ch2)

Check if ch1 is greater than ch2.

Returns:

TRUE if ch1 is greater than ch2, FALSE otherwise.

const func boolean: (in char: ch1) <= (in char: ch2)

Check if ch1 is less than or equal to ch2.

Returns:

TRUE if ch1 is less than or equal to ch2, FALSE otherwise.

const func boolean: (in char: ch1) >= (in char: ch2)

Check if ch1 is greater than or equal to ch2.

Returns:

TRUE if ch1 is greater than or equal to ch2, FALSE otherwise.

const func char: (attr char) conv (in integer: number)

Convert an integer number to a character. For values between 0 and 1114111 a Unicode character is returned. For values between 1114112 and 1114500 a cursor or function key is returned. For -1 the value EOF is returned.

Returns:

a character which corresponds to the given integer.

Raises:

RANGE_ERROR - If the number does not fit into a 32-bit char.

const func char: (attr char) parse (in string: stri)

Convert a string with a length of 1 to a character.

char parse "a"   returns 'a'
char parse " "   returns ' '
char parse "aa"  raises RANGE_ERROR
char parse "  "  raises RANGE_ERROR
char parse ""    raises RANGE_ERROR

Returns:

the first character of the string.

Raises:

RANGE_ERROR - If the length of the string is not 1.

const func integer: compare (in char: ch1, in char: ch2)

Compare two characters.

Returns:

-1, 0 or 1 if the first argument is considered to be respectively less than, equal to, or greater than the second.

const func integer: hashCode (in char: ch)

Compute the hash value of a character.

Returns:

the hash value.

const func integer: ord (in char: ch)

Get the ordinal number of a character. For Unicode characters a value between 0 and 1114111 is returned. For cursor and function keys a value between 1114112 and 1114500 is returned. For EOF the value -1 is returned.

Returns:

the ordinal number of a character.

const func integer: integer (in char: ch)

Get the ordinal number of a character. For Unicode characters a value between 0 and 1114111 is returned. For cursor and function keys a value between 1114112 and 1114500 is returned. For EOF the value -1 is returned.

Returns:

the ordinal number of a character.

const func char: chr (in integer: number)

Convert an integer number to a character. For values between 0 and 1114111 a Unicode character is returned. For values between 1114112 and 1114500 a cursor or function key is returned. For -1 the value EOF is returned.

Returns:

a character which corresponds to the given integer.

Raises:

RANGE_ERROR - If the number does not fit into a 32-bit char.

const func char: char (in integer: number)

Convert an integer number to a character. For values between 0 and 1114111 a Unicode character is returned. For values between 1114112 and 1114500 a cursor or function key is returned. For -1 the value EOF is returned.

Returns:

a character which corresponds to the given integer.

Raises:

RANGE_ERROR - If the number does not fit into a 32-bit char.

const func char: succ (in char: ch)

Successor of a character.

Returns:

chr(ord(ch) + 1)

const func char: pred (in char: ch)

Predecessor of a character.

Returns:

chr(ord(ch) - 1)

const func string: str (in char: ch)

Create a string with one character.

Returns:

a string with the character ch.

const func char: upper (in char: ch)

Convert a character to upper case. The conversion uses the default Unicode case mapping, where each character is considered in isolation. Characters without case mapping are left unchanged. The mapping is independent from the locale. Individual character case mappings cannot be reversed, because some characters have multiple characters that map to them.

Returns:

the character converted to upper case.

const func char: lower (in char: ch)

Convert a character to lower case. The conversion uses the default Unicode case mapping, where each character is considered in isolation. Characters without case mapping are left unchanged. The mapping is independent from the locale. Individual character case mappings cannot be reversed, because some characters have multiple characters that map to them.

Returns:

the character converted to lower case.

const func boolean: isLetter (in char: ch)

Determines if the specified character ch is a letter. A character is considered to be a letter if the category from the Unicode specification is any of the following:

• UPPERCASE_LETTER (Lu)
• LOWERCASE_LETTER (Ll)
• TITLECASE_LETTER (Lt)
• MODIFIER_LETTER (Lm)
• OTHER_LETTER (Lo)

Examples:

isLetter('A')          returns TRUE
isLetter('\16#4e2d;')  returns TRUE
isLetter('4')          returns FALSE
isLetter('+')          returns FALSE
isLetter('\t')         returns FALSE
isLetter(KEY_LEFT)     returns FALSE
isLetter(EOF)          returns FALSE

Returns:

TRUE if ch is a letter, FALSE otherwise.

const func integer: width (in char: ch)

Number of screen columns occupied by the Unicode character ch. Non-spacing characters and control characters have width of 0.

width('\n')         returns 0
width('\t')         returns 0
width(KEY_LEFT)     returns 0
width(EOF)          returns 0
width('A')          returns 1
width('\16#4e2d;')  returns 2

Returns:

0,1 or 2 depending on the width occupied on a terminal.

const proc: incr (inout char: ch)

Increment a character. This is equivalent to:

ch := succ(ch);

const proc: decr (inout char: ch)

Decrement a character. This is equivalent to:

ch := pred(ch);

const func char: rand (in char: low, in char: high)

Compute pseudo-random character in the range [low, high]. The random values are uniform distributed.

Returns:

a random character such that low <= rand(low, high) and rand(low, high) <= high holds.

Raises:

RANGE_ERROR - The range is empty (low > high holds).

const func char: char (in string: stri)

Convert a string with a length of 1 to a character.

char("a")   returns 'a'
char(" ")   returns ' '
char("aa")  raises RANGE_ERROR
char("  ")  raises RANGE_ERROR
char("")    raises RANGE_ERROR

Returns:

the first character of the string.

Raises:

RANGE_ERROR - If the length of the string is not 1.

const func string: trimValue (attr char, in string: stri)

Trim a string such that it can be converted to char.

trimValue(char, " 1 ")             returns "1"
trimValue(char, "   ")             returns " "
trimValue(char, "\t ")             returns "\t"
trimValue(char, "")                returns ""
char parse trimValue(char, " 1 ")  returns '1'
char parse trimValue(char, "   ")  returns ' '
char parse trimValue(char, "\t ")  returns '\t'
char parse trimValue(char, "")     raises RANGE_ERROR

Returns:

the trimmed string.

const func string: literal (in char: ch)

Conversion to a char literal.

Returns:

the character literal of ch.