read_until

read_until — reads characters, constructing a string as it goes.

Syntax

read_until (file, delimiters)

		

Arguments

file

A file pointer to a previously opened file. This may be either a file in the file system, or a string opened for read and write.

delimiters

A string of delimiter characters. "" indicates white space.

Returns

All characters in the file up to the first occurrence of any of delimiter characters, or "Unexpected end of file".

Description

This function reads characters from the input file one at a time until it reaches any of the delimiter characters, constructing a string as it goes. Successive calls continue from the point of the previous read_until. If the end of file is reached, the function returns "Unexpected end of file".

Example

An input file contains the following:

      Lists can be
      expressed as (a b c).

Successive calls to read_until will produce:

Gamma> ft = open ("myreadlfile.dat","r");
#<File:"myreadlfile.dat">
Gamma> read_until(ft, "(");
"Lists can be\nexpressed as "
Gamma> read_until(ft,"x");
"a b c)."
Gamma> read_until(ft,"y");
"Unexpected end of file"
Gamma> 
		

See Also

read, read_char, read_double, read_float, read_line, read_long, read_short