[r6rs-discuss] [Formal] Change the "add-prefix" import syntax in libraries

[MichaelL at frogware.com]

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Name: Michael Lenaghan
Email: michaell at frogware.com
Type: Simplification
Priority: Minor
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.
                1. To add as a prefix.
                2. 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".