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Counting leading spaces

I want to count the leading spaces in a string. I can sort of do it, as shown in the sample below, but the core of the problem seems to be finding the first non-blank character. It seems like there must be a better way than specifying a list of 127 printable characters and then finding any one of them. I don't want to find "something," but rather "anything" as long as it is NOT a blank.
    
Thank you.
    
R E B O L []
    
;;;;;         1         2         3
;;;;; 123456789*123456789*123456789*
STR: "        XXXXXXXX YYYYY"
    
NONBLANK: charset "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
    
FIRST-NONBLANK: index? find STR NONBLANK
LEADING-SPACES: FIRST-NONBLANK - 1
REST-OF-STRING: at STR FIRST-NONBLANK
    
print ["String value: " REST-OF-STRING]
print ["Leading spaces: " LEADING-SPACES]
    
halt

posted by:   Steven White       22-Nov-2017/12:17:53-8:00



You can use COMPLEMENT:
    
     nonblanks: complement blanks: charset " "
    
FIND/INDEX? is one way to go about things, can also PARSE:
    
     parse/all [ ; /ALL assuming Rebol 2
         copy leading-spaces any blanks
         first-nonblank:
         copy rest-of-string to end
     ]


posted by:   Chris       22-Nov-2017/12:53:24-8:00



That should of course be:
    
     parse/all str [...]

posted by:   Chris       22-Nov-2017/12:54:48-8:00



Note that charsets can also be defined like this:
    
charset [#"0" - #"9" #"A" - #"Z" #"a" - #"z"]

posted by:   Nick       23-Nov-2017/7:02:48-8:00



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