Initializing help system before first use

getcharclass

Purpose
Get character class of a symbol.
Synopsis
function getcharclass(charcode:integer):integer
function getcharclass(txt:string|text, index:integer):integer
function getcharclass(txt:string|text):integer
Arguments
txt 
A text object or a string
index 
Position of the character
charcode 
A Unicode codepoint
Return value
The character class as a bit-encoded integer or SYS_CCLASS_INVALID if the string is empty or the requested position is invalid.
Example
The following example defines a function that checks whether a text string is a valid Mosel identifier: 
function ident_valid(id:text):boolean
 returned:=
    id.size>0 and
    bittest(getcharclass(id),
        SYS_CCLASS_ALPHA+SYS_CCLASS_USCORE+SYS_CCLASS_NOASCII)<>0 and
    and(i in 2..id.size) bittest(getcharclass(id,i),
        SYS_CCLASS_ALPHA+SYS_CCLASS_USCORE+SYS_CCLASS_NOASCII+SYS_CCLASS_DIGIT)<>0
end-function
Further information
1. The returned class may include any of the following components:
SYS_CCLASS_ALPHA 
Ascii alphabetic (A-Z,a-z)
SYS_CCLASS_DIGIT 
Digit (0-9)
SYS_CCLASS_HEXLET 
Hexadecimal letter (A-F,a-f)
SYS_CCLASS_SPACE 
Space (\t,\n,\v,\f,\r, )
SYS_CCLASS_USCORE 
Underscore (_)
SYS_CCLASS_SGLQ 
Single quote (')
SYS_CCLASS_NOASCII 
Non ascii character (codepoint is greater than 127)
SYS_CCLASS_SPEC 
Special character (codepoints 0-31,127)
SYS_CCLASS_NQSAF 
Symbol exported without quoting in data files (+,-,.,~,_)
SYS_CCLASS_DQESC 
Symbol requiring escaping in double quoted strings (",\)

2. The third form of the function will return the character class of the first symbol of the string or -1 if the string is empty.
Related topics
getchar
Module
mmsystem

Parent Topic Procedures and functions

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