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-rw-r--r-- | NEWS | 55 |
1 files changed, 55 insertions, 0 deletions
@@ -383,6 +383,61 @@ want to re-export bindings, use the new `re-export' in place of `export'. The new `re-export' will not make copies of variables when rexporting them, as `export' did wrongly. +** Module system now allows selection and renaming of imported bindings + +Previously, when using `use-modules' or the `#:use-module' clause in +the `define-module' form, all the bindings (association of symbols to +values) for imported modules were added to the "current module" on an +as-is basis. This has been changed to allow finer control through two +new facilities: selection and renaming. + +You can now select which of the imported module's bindings are to be +visible in the current module by using the `:select' clause. This +clause also can be used to rename individual bindings. For example: + + ;; import all bindings no questions asked + (use-modules (ice-9 common-list)) + + ;; import four bindings, renaming two of them; + ;; the current module sees: every some zonk-y zonk-n + (use-modules ((ice-9 common-list) + :select (every some + (remove-if . zonk-y) + (remove-if-not . zonk-n)))) + +You can also programmatically rename all selected bindings using the +`:renamer' clause, which specifies a proc that takes a symbol and +returns another symbol. Because it is common practice to use a prefix, +we now provide the convenience procedure `symbol-prefix-proc'. For +example: + + ;; import four bindings, renaming two of them specifically, + ;; and all four w/ prefix "CL:"; + ;; the current module sees: CL:every CL:some CL:zonk-y CL:zonk-n + (use-modules ((ice-9 common-list) + :select (every some + (remove-if . zonk-y) + (remove-if-not . zonk-n)) + :renamer (symbol-prefix-proc 'CL:))) + + ;; import four bindings, renaming two of them specifically, + ;; and all four by upcasing. + ;; the current module sees: EVERY SOME ZONK-Y ZONK-N + (define (upcase-symbol sym) + (string->symbol (string-upcase (symbol->string sym)))) + + (use-modules ((ice-9 common-list) + :select (every some + (remove-if . zonk-y) + (remove-if-not . zonk-n)) + :renamer upcase-symbol)) + +Note that programmatic renaming is done *after* individual renaming. +Also, the above examples show `use-modules', but the same facilities are +available for the `#:use-module' clause of `define-module'. + +See manual for more info. + ** The semantics of guardians have changed. The changes are for the most part compatible. An important criterion |