Outlining optional modules.

3 files changed, 32 insertions, 6 deletions

diff --git a/README.md b/README.md
index 69c3338..99649f7 100644
--- a/README.md
+++ b/README.md
@@ -6,4 +6,29 @@ support any draft prior to v1.0.0.*
 
 As implementers work to build their own parsers, testing scripts may be
 contributed to the 'scripts' directory, and code snippets (e.g. for lambdas)
-may be provided as well (location TBD).
+may be provided as well.
+
+Optional Modules
+----------------
+
+Specification files beginning with a tilde (~) describe optional modules.  At
+present, the only module being described as optional is regarding support for
+lambdas.  As a guideline, a module may be a candidate for optionality when:
+
+  * It does not affect the core syntax of the language.
+  * It does not significantly affect the output of rendered templates.
+  * It concerns implementation language features or data types that are not
+    common to or core in every targeted language.
+  * The lack of support by an implementation does not diminish the usage of
+    Mustache in the target language.
+
+As an example, the lambda module is primarily concerned with the handling of a
+particular data type (code).  This is a type of data that may be difficult to
+support in some languages, and users of those languages will not see the lack
+as an 'inconsistency' between implementations.
+
+Support for specific pragmas or syntax extensions, however, are best managed
+outside this core specification, as adjunct specifications.
+
+Implementors are strongly encouraged to support any and all modules they are
+reasonably capable of supporting.
diff --git a/TESTING.md b/TESTING.md
index cb06e74..f7ecea5 100644
--- a/TESTING.md
+++ b/TESTING.md
@@ -11,9 +11,12 @@ In general, the process for each `.yml` file is as follows:
   1. Ensure that each element of the 'partials' hash (if it exists) is
      stored in a place where the interpreter will look for it.
 
-  2. If your implementation supports lambdas, ensure that each member of 'data'
-     tagged with '!code' is properly processed into a language-specific
-     lambda reference.
+  2. If your implementation will not support lambdas, feel free to skip over
+     the optional '~lambdas.yml' file.
+
+  2.1. If your implementation will support lambdas, ensure that each member of
+       'data' tagged with '!code' is properly processed into a language-
+       specific lambda reference.
 
       *   e.g. Given this YAML data hash:
 
@@ -27,8 +30,6 @@ In general, the process for each `.yml` file is as follows:
       *   If your implementation language does not currently have lambda
           examples in the spec, feel free to implement them and send a pull
           request.
-      *   If your implementation does not support lambdas, feel free to skip
-          over the `lambdas.yml` file.
 
   3. Render the template (stored in the 'template' key) with the given 'data'
      hash.
diff --git a/specs/lambdas.yml b/specs/~lambdas.yml
index 692b41b..692b41b 100644
--- a/specs/lambdas.yml
+++ b/specs/~lambdas.yml