Formal comment #81 (simplification)

Change the "add-prefix" import syntax in libraries
Reported by:	Michael Lenaghan

Component:	libraries
Version:	5.91

Section: 6.1 Library form (pg 21) 

Dependencies: 6.4 Examples (pg 25) 

Summary

Change the "add-prefix" import syntax in libraries to make it slightly
more consistent or add "drop-prefix" to make the inconsistency
worthwhile.

Description

An <import set> is defined as: 
        <library reference>
        (only <import set> <identifier> ...)
        (except <import set> <identifier> ...)
        (add-prefix <import set> <identifier>)
        (rename <import set> (<identifier> <identifier>) ...)

"add-prefix" stands out in this list because of its verb-noun
form. Strictly speaking, the difference isn't warranted; "prefix" is a
verb as well as a noun (http://www.answers.com/prefix&r=67):

1. To put or attach before or in front of.

2. To settle or arrange in advance.

3. Grammar. 
     To add as a prefix. 
     To add a prefix to. 

PLT Scheme (
http://download.plt-scheme.org/doc/352/html/mzscheme/mzscheme-Z-H-5.html#node_chap_5
) uses "prefix" as a verb with other modifiers:

        require
                prefix
                prefix-all-except

        provide
                prefix-all-defined
                prefix-all-defined-except

The use of "add-prefix" in the context of R6RS may have its roots in
Chez Scheme (http://www.scheme.com/csug7/syntax.html#./syntax:h5):

        add-prefix
        drop-prefix

Here at least the reason for the difference in form is readily
apparent.

Recommendation

Change "add-prefix" to "prefix" or add "drop-prefix".

RESPONSE:

For the next draft of R6RS, we will change "add-prefix" to "prefix".