HELP DISCIN Steven Hardy, January 1978
Revised by John Williams, May 1993
discin(file_name) -> char_rep
The procedure discin takes a file name as argument, and returns a
character repeater procedure (analogous to * charin), which reads
characters one at a time from the given file.
For example:
discin('myfile.p') -> rep;
This creates a character repeater procedure for the file 'myfile.p'
and assigns it to the variable "rep". Successive calls of "rep", i.e.
rep() -> char;
return successive characters from the file 'myfile.p'. The special
object * termin is returned when the end of the file is reached.
If the file name given to discin is a word, the value of the variable
* pop_default_type (normally '.p') is appended to that word, so
discin("myfile")
and
discin('myfile.p')
are equivalent.
discin can also be given a * DEVICE record as argument, in which case a
procedure that reads successive characters from that device is created.
The underlying device record associated with a character repeater
produced by discin can be accessed with the procedure * discin_device.
This can be useful if you want to test for input on the device, or close
it, for example. See REF * CHARIO for more details.
See also:
HELP * DISCOUT for creating character consumer procedures
HELP * DEVICE introduction to Poplog "device" records
HELP * INCHARITEM procedure for converting character repeaters
to item repeaters
REF * CHARIO reference guide to Poplog character stream i/o
--- C.all/help/discin
--- Copyright University of Sussex 1993. All rights reserved.