Subject: bug#58001: Cannot use 'read' in imported library

From: [email-masked]
Date: Thu, 22 Sep 2022 00:30:40 -0700

I'm using Guile version 3.0.5 from the Guix repository.

I've run into a strange issue with the read function from (scheme 
base). It cannot be used in an R7RS-style library. This only seems to 
apply to the read function. Other standard procedures work fine.

Let's say you have a library that uses read. Maybe it looks like this:

;; File: foo.scm
(define-library (foo)
  (import (scheme base))
  (export read-wrapped)
  (begin
    (define (read-wrapped port) (read port))))

Now, let's say you want to import that library somewhere else and use 
it's exported function read-wrapped:

;; File: main.scm
(import (scheme base))
(import (foo))
(display (read (current-input-port)))
(display (read-wrapped (current-input-port)))

If you try to run that main script (in the same directory as the foo 
library):

GUILE_LOAD_PATH=. guile --r7rs main.scm

You can enter get a datum for the first call to read, then you'll get 
an error for the second call:

foo.scm:1:0: In procedure read-wrapped:
Unbound variable: read

This only happens with read. If you replace read with a different 
standard procedure like boolean? then everything is fine (you'll see #f 
twice because the input port fails the predicate).

I'm pretty baffled. I've attached the dummy source files for 
convenience.