Chicken allows for shadowing syntax in a way disallowed by R5RS/sec.5.3

[Jeronimo Pellegrini]

Hi,

With master/HEAD, (latest commit is 8acb3f92df82f369fc5dbef8f7c44a68468a92c3):

#;7> (define define (lambda () 'z))
#;8> define
#<procedure (define)>
#;9> (define)

Error: (car) during expansion of (define ...) - bad argument type: ()

    Call history:

    <syntax>        (define)    <-- 
#;9> (let ((a define)) (a))
z
#;10> 

But section 5.3 of R5RS explicitly disallows defining define among other things (it mentions "(define define 3)" as an example of error, and Chicken allows it).

This is not listed in the "Deviations form the standard" section of the manual, so it's not clear if it's a bug or an intended deviation.

P.S.: Bigloo does the same;
Chibi signals an error;
Guile shadows the define syntax even when it's in procedure-calling position: "(define)" above works in Guile and returns the symbol z!

[felix winkelmann]

Yes, this is an error, but the implementation is free to handle it in whatever way it likes (at least that is my understanding of the term "is an error").

I will add a note to the manual that describes the current behaviour.

[felix winkelmann]

I consulted Alex and will make

(define define ...)

and

(define-syntax define-syntax ...)

signal an error.

[felix winkelmann]

See 9fd71180ce4c45d5b81051f1e942ef135450a9f8 and d318031ff9305bd43be631f5f4f2c6b4a282c15a (master).

This implements the changes noted in the last comment and is sufficient, IMHO.

[felix winkelmann]

Replying to felix:

See 9fd71180ce4c45d5b81051f1e942ef135450a9f8 and d318031ff9305bd43be631f5f4f2c6b4a282c15a (master).

This implements the changes noted in the last comment and is sufficient, IMHO.

(experimental branch, not master).

[felix winkelmann]

Milestone 4.6.0 deleted