* make-d-macro-char.diff

Currently, invoking MAKE-DISPATCH-MACRO-CHARACTER on a character that's already been made a dispatch macro character results in an error.

All other implementations I tested, do not signal an error, but just override a possibly existing dispatch table.

I think that's sensible, as the the CLHS entry for MAKE-D-M-CHAR says Exceptional Situations are None.

* get-dtable-pair.diff

The implementation for retrieving an entry from the dispatch tables is currently duplicated on all call sites.

This patch introduces an explicit getter function.

Also, in SET-DISPATCH-MACRO-CHARACTER the function argument was COERCED to a function (thus allowing literal lambda expressions), use %COERCE-TO-CALLABLE instead.

* inline-assert-not-std-rt.diff

Inline ASSERT-NOT-STANDARD-READTABLE, and MAKE-DISPATCH-CHAR-TABLE.

* char-attr-table-type.diff

Introduce an explicit type for character attributes (CHAR-ATTR), and rename the type ATTRIBUTE-TABLE to CHAR-ATTR-TABLE.

* ref-cat-entry.diff

Fix more FIXMES and code duplication by introducing a low-level getter REF-CAT-TABLE which is then used at the appropriate places.

-T.