R6RS Standard Libraries for R7RS Systems

This package makes one or more of the R6RS standard libraries available for use by R7RS libraries and programs.

The R6RS standard specifies a set of (rnrs *) libraries. Most of those libraries have been ported to R7RS and placed in the (r6rs *) hierarchy. (This trivial renaming avoids conflict with the original R6RS libraries, which are provided by some implementations of the R7RS.)

The R6RS documentation of its (rnrs *) libraries serves as primary documentation for the corresponding (r6rs *) libraries:

• The Revised⁶ Report on the Algorithmic Language Scheme specifies the (rnrs base) library.
• The Revised⁶ Report on the Algorithmic Language Scheme — Standard Libraries specifies all other (rnrs *) libraries.

Implementation

If an R7RS system provides an (rnrs *) library, as detected by cond-expand, the corresponding (r6rs *) library may just import the R6RS library and re-export the imported identifiers. Otherwise the R6RS library is approximated by portable R7RS code.

Tests

The (r6rs *) libraries have been tested using test programs derived from Racket's R6RS test suite. These test programs have not been refactored to make them compatible with Snow's standards for test programs.

Bugs

Please report bugs found within the (r6rs *) libraries at Larceny's GitHub site. (Caveat: The current test suite detects several bugs that lie within particular implementations of the R7RS, not within the (r6rs *) libraries themselves.)

As with most ports from one language standard to another, some compromises were necessary:

• (r6rs base) exports identifier-syntax, but it's just a stub that raises a syntax exception if you try to use it.
• (r6rs io ports) exports stubs for several procedures and syntaxes that cannot be implemented portably in R7RS (small).
• The R7RS implementation of (r6rs hashtables) uses (rnrs hashtables) if that library is available. Otherwise it implements R6RS hashtables on top of SRFI 69 hash tables, provided (srfi 69) is available. Otherwise it implements R6RS hashtables on top of the reference implementation of SRFI 69, which is not very good.