Re: Using include-file

On 2024-09-03 10:50, Anton Ertl wrote:

Ruvim <ruvim.pinka@gmail.com> writes:

Do you know practical cases of using "include-file" in programs?

 One way I am thinking about is to implement INCLUDED etc.  Systems
deal differently with relative filenames for INCLUDED, with less
differences for OPEN-FILE.  So if I want to implement a certain
handling of relative filenames for INCLUDED in order to get rid of
system differences, one way to do it is to do it for OPEN-FILE and
then perform INCLUDE-FILE.

Yes, overriding the system's file search mechanism used by "included" is a very interesting idea!

 

Using other system-specific means, this word can probably be used to
organize inter-process communication: when a file descriptor (e.g. a
pipe) is passed from one process to another and used as the input
source.  But why do you need to load Forth code this way?

 Heinz Schnitter implemented Open Network Forth, a distributed system,
where the parts communicated by sending Forth source code to each
other.  One could implement that by having network connections
(telnet-style or ssh-style) between the parts, and the receiver could
INCLUDE-FILE the file-id that represents his end of the connection.
However, Open Network Forth was written around 1984, long before
INCLUDE-FILE was standardized.  Bernd Paysan uses ideas from it in his
work, inclluding sending Forth commands between tasks, but AFAIK does
not use INCLUDE-FILE for that.

Such a system must probably be multitasking. Otherwise, the Forth system instance that runs "read-file" is a slaver of the corresponding pipe emitter until the pipe is closed (i.e., until the master wants).
Taking my idea of skipping a BOM (byte-order mark), a program can also skip a shebang line, like this:
   #! /usr/bin/env forth
I know Gforth has the word "#!" that comments out the rest of the line.
Using "open-file", "read-line", "reposition-file" and "include-file" is an alternative way for a portable program. Yes, it seems far more complex than a word "#!". But what if you need "#!" for something else (including recognizable things).
--
Ruvim