fronttoken
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: fronttoken
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BAP Online Manuals : Library Reference : Library by Name : fronttoken
Previous: frontstr
Next: get
Previous: frontstr
Next: get
6.2.63. fronttoken
extracts the first token in front of a string
SYNOPSIS
fronttoken("Hello World",Token,RestString)
SYNTAX
fronttoken(String,Token,RestString) (i,x,x)
ARGUMENTS
string(String) (i) string to be separated
string(Token) (x) first Token contained in String
string(RestString) (x) String without its leading white spaces characters and
Token
DESCRIPTION
Fronttoken() skips all white space characters (blanks,tabs) and separates from the
resulting string the first valid token. The remainder is matched with RestString. A valid
token is either a variable or name
EXAMPLE
readln(Input), % e.g. enter "3+5", "4*6" fronttoken(Input,T1,,R1), fronttoken(R1,Op,T2), str_int(T1,I1),str_int(T2,I2), Expr =.. [Op,I1,I2], Sum is Expr, write(Sum),nl.
ERRORS
A runtime error occurs if the arguments belong to the wrong domain.
LAYERS
prolog-process, client-server, object
RELATED PREDICATES
frontchar , str_char , frontchar ,
prologtoken , concat , str_len
BAP Online Manuals : Library Reference : Library by Name : fronttoken
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Next: get