This site is a static rendering of the Trac instance that was used by R7RS-WG1 for its work on R7RS-small (PDF), which was ratified in 2013. For more information, see Home.

Source for wiki CaseSensitivity version 6

author

arcfide

comment

ipnr

99.31.12.26

name

CaseSensitivity

readonly

text

Historically one of the most heated flame-wars in the Scheme
community.  We have to decide whether we want to preserve backwards
compatibility with standards up through the R5RS, or reaffirm the
switch to case-sensitivity in the R6RS.  The charter gives precedence
to the former, so unless we can reach a rough consensus (> 90%) to the
contrary, the default should remain case-insensitive.

Whatever we choose we should realize that some implementations are likely
to use a different default in their preferred environments.

Note that the default case-sensitivity is orthogonal to the issue of
whether and how behavior can be toggled on a per-file or
per-expression basis.  If there is a toggle, it may be specified by
WG1 for both groups, or only by WG2.

Below are some common arguments for each side.

'''Pro-folding:'''

    * R[0-5]RS and IEEE Scheme compatible
    * code from R5RS and before continues to work
    * possibly easier for beginners not expecting case distinctions to be significant
    * allows using different cases as stylistic differences in source
    * prevents using separate identifiers which differ only in case
    * less confusion when code is read aloud, e.g. variable names

'''Pro-preserving:'''

    * R6RS compatible
    * the popular default in a number of modern implementations
    * easier compatibility with external data (XML, some filesystems, FFIs)
    * users from other languages usually expect case sensitivity
    * using different cases for the same identifier can be confusing
    * transliterations of math formulae may be easier to read with case distinctions
    * more general - can write a (begin/ci ...) macro to implement the alternative
    * allows using separate identifiers which differ only in case (e.g., capitalizing a class but not an instance)
    * simpler to implement in the presence of complex character sets

time

2010-02-13 14:58:54