Character input/output

• get_char(Stream,Char):   Inputs a character (if Stream is a text stream) or a byte (if Stream is a binary stream) from the stream Stream and unifies it with Char. After reaching the end of file, it unifies Char with end_of_file.

• get_char(Char):   The same as the previous one except that the current input stream is used.

• peek_char(Stream,Char):   The current character in Stream is Char. The position pointer of Stream remains the same after this operation.

• peek_char(Char):   The same as peek_char(Stream,Char) except that the current input stream is used.

• put_char(Stream,Char):   Outputs the character Char to the stream Stream.

• put_char(Char):   Outputs the character Char to the current output stream.

• nl(Stream):   Outputs the new line character to the stream Stream.

• nl:   Outputs the new line character to the current output stream.

• readLine(X):   The call readLine(X) reads a line from the current input stream as character codes. (not in ISO).

• readFile(Name,Content):   Reads a text file and binds Content to the list of character codes in the file. (not in ISO).