[ Character I/O | The ECLiPSe Built-In Predicates | Reference Manual | Alphabetic Index ]
read_string(+Delimiters, ?Length, ?String)
Reads a string from the input stream up to a delimiter or up to a specified
length.
- +Delimiters
- String or atom.
- ?Length
- Integer or variable.
- ?String
- String or variable.
Description
A string of characters is read from the input up to one character which
occurs in the delimiter string Delimiters. This character is also
consumed, but does not appear in the string which is unified with
String.
Two symbolic Delimiters can be specified:
end_of_line a newline or carriage-return/newline sequence
end_of_file the end of the file/input
End of file always acts like a delimiter.
If Length is a variable, it is unified with the length of the string
String. If Length is an integer, the number of characters read from
the input is limited by the Length.
Fail Conditions
Fails if String does not unify with the next string of characters read
from input satisfying the described conditions. The default handler for
the error 190 also lets the predicate fail.
Resatisfiable
No.
Exceptions
- (4) instantiation fault
- Delimiters is not instantiated.
- (5) type error
- Delimiters is not a string or atom.
- (5) type error
- Length is not an atom or an integer.
- (5) type error
- String is not an atom or a string.
- (6) out of range
- Delimiters is an atom but not a valid symbolic delimiter.
- (190) end of file reached
- End of file was encountered before reading any character.
- (198) reading past the file end
- Trying to read even after the error 190 was raised.
Examples
Equivalent to read_string(input, Delimiters, Length, String). (see
read_string/4 for details).
See Also
read_string / 4, read_token / 2, read_token / 3, open / 3