[r6rs-discuss] [Formal] SRFI-39 should be made an R6RS library

[John Cowan]

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Submitter: John Cowan
Email address: cowan at ccil.org
Issue type: Enhancement
Priority: Major
Component: Other
Report version: 5.92
Summary: SRFI-39 should be made an R6RS library

I have searched the various status reports and seen nothing about
dynamic binding, dynamic variables, or parameters.  I suggest
that SRFI-39 be incorporated into R6RS as the (r6rs parameters)
library.

The reason for making parameters part of the standard, beside their
general utility, is that they are intertwingled with the current-*-port
facilities, which are explicitly specified as parameters by SRFI-39.
As a result, it is hard to load a portable implementation of parameters
into a Scheme that doesn't have it; current-*-port cannot be rebound
by parameterize correctly.

Judging by the SRFI-39 mail archives, the only thing controversial
about the final form of the SRFI is the behavior when interacting
with threads.  As threads are not part of R6RS, the issue does not
arise.

SRFI-39 is already provided by at least Guile, Kawa, Gambit, SISC,
RScheme, scsh, Gauche, STklos, and Chicken.

-- 
John Cowan  cowan at ccil.org  http://ccil.org/~cowan
The competent programmer is fully aware of the strictly limited size of his own
skull; therefore he approaches the programming task in full humility, and among
other things he avoids clever tricks like the plague.  --Edsger Dijkstra