[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Chicken-users] set! on unbound variable

From: John Cowan
Subject: Re: [Chicken-users] set! on unbound variable
Date: Sat, 24 Sep 2016 14:17:18 -0400

On Sat, Sep 24, 2016 at 11:39 AM, Dan Leslie <address@hidden> wrote:

It seems that Chicken has a parameter to enforce R5RS strictness:

> -r5rs-syntax disables the Chicken extensions to R5RS syntax

All that does is disable the syntax keywords that are normally available but are not part of R5RS, so it's not relevant here.  In any case, R5RS does allow the approach Chicken takes to unknown variables.  Section 5.2.1. says:

Some implementations of Scheme use an initial environment in which all possible variables are bound to locations, most of which contain undefined values. Top level definitions in such an implementation are truly equivalent to assignments.

See for which Schemes do this
and which do not.

John Cowan        address@hidden
After fixing the Y2K bug in an application:
        WELCOME TO <censored>
        DATE: MONDAK, JANUARK 1, 1900

reply via email to

[Prev in Thread] Current Thread [Next in Thread]