www

commit 54d3b54230d7cbbd699f7880e63a6f0bf2ad8cc0
parent 30be092c1b51f96a79bcb6fab9c8473cde763585
Author: Georges Dupéron <georges.duperon@gmail.com>
Date:   Fri, 23 Sep 2016 02:02:21 +0200

Added caveat about module boundaries in the documentation and README

Diffstat:
M
README.md
 | 
20
++++++++++++++++++++
M
private/no-order.rkt
 | 
5
+++++
M
scribblings/extensible-parser-specifications.scrbl
 | 
18
++++++++++++++++++

3 files changed, 43 insertions(+), 0 deletions(-)
diff --git a/README.md b/README.md
@@ -6,6 +6,26 @@
 extensible-parser-specifications
 ================================
 
+
+Caveat: the mixins defined with `define-eh-alternative-mixin` cannot be
+provided and used in a separate module. Unfortunately, I cannot think of an
+acceptable fix for this problem, as solving this would require extracting
+parts of the mixin while preserving the bindings of some identifiers, but
+altering the bindings of others. This means that for the foreseeable future,
+once a mixin is defined, can only be used via `~mixin` (or by directly
+invoking it) within the same module.
+
+The regular and splicing syntax classes defined with `#:define-syntax-class`
+and `#:define-splicing-syntax-class` will work fine across module boundaries,
+however. Manually defined syntax classes, splicing syntax classes or
+ellipsis-head syntax classes will also work fine across module boundaries,
+even if they contain uses of `~no-order` and `~seq-no-order`, and even if
+those special forms contain uses of mixins defined within the same module. In
+other words, as long as a definition of a mixin and all its uses via `~mixin`
+are within the same module, everything else should work without surprises.
+
+----------
+
 Like https://github.com/AlexKnauth/seq-no-order, but provides global
 constraints.  AlexKnauth's implementation allows dotted "rest" pattern which
 this implementation does not support.
diff --git a/private/no-order.rkt b/private/no-order.rkt
@@ -149,6 +149,11 @@
                      [lift-rest add-to-lift-rest!])
         (define alts
           (expand-all-eh-mixin-expanders #'(~or pat ...)))
+        ;; TODO: we can probably close the "parameterize" here.
+
+
+
+        
         ;; NOTE: this works only because eh-mixin-expanders are NOT pattern
         ;; expanders. If these are merged later on, then this needs to be
         ;; adjusted
diff --git a/scribblings/extensible-parser-specifications.scrbl b/scribblings/extensible-parser-specifications.scrbl
@@ -11,6 +11,24 @@
 @title{extensible-parser-specifications}
 @author{@author+email["Georges Dupéron" "georges.duperon@gmail.com"]}
 
+Caveat: the mixins defined with @racket[define-eh-alternative-mixin] cannot be
+provided and used in a separate module. Unfortunately, I cannot think of an
+acceptable fix for this problem, as solving this would require extracting parts
+of the mixin while preserving the bindings of some identifiers, but altering the
+bindings of others. This means that for the foreseeable future, once a mixin is
+defined, can only be used via @racket[~mixin] (or by directly invoking it)
+within the same module.
+
+The regular and splicing syntax classes defined with
+@racket[#:define-syntax-class] and @racket[#:define-splicing-syntax-class] will
+work fine across module boundaries, however. Manually defined syntax classes,
+splicing syntax classes or ellipsis-head syntax classes will also work fine
+across module boundaries, even if they contain uses of @racket[~no-order] and
+@racket[~seq-no-order], and even if those special forms contain uses of mixins
+defined within the same module. In other words, as long as a definition of a
+mixin and all its uses via @racket[~mixin] are within the same module,
+everything else should work without surprises.
+
 @defmodule[extensible-parser-specifications]
 
 @include-section{defining-reusable-mixins.scrbl}