Adds initial topic for definitions (#76)

resolves #2

Author: vulder

sources/knowledge_areas.dat

@@ -12,7 +12,8 @@ P Preprocessor
 	? ? ? ? Macros
 B Basics Types, Objects, Values, Expressions, Statements, and Control-Flow Constructs
 	? ? ? ? Constant Objects
-	? ? ? ? Declarations and Definitions
+	? ? ? ? Declarations
+	def y y y Definitions
 	? ? ? ? Selection Constructs (e.g., if, ternary)
 	? ? ? ? Looping Constructs (e.g., for, while, etc.)
 F Functions

sources/modules/object-model/definitions.md

@@ -0,0 +1,115 @@
+## C++ object model: Definitions {#def}
+
+_Skeleton descriptions are typeset in italic text,_
+_so please don't remove these descriptions when editing the topic._
+
+### Overview
+
+_Provides a short natural language abstract of the module’s contents._
+_Specifies the different levels of teaching._
+
+------------------------------------------------------------------------
+Level             Objective
+----------------- ------------------------------------------------------
+Foundational      Defining variables and ODR
+
+Main              Defining for programs
+
+Advanced          Special cases and peculiarities
+
+------------------------------------------------------------------------
+
+### Motivation
+
+_Why is this important?_
+_Why do we want to learn/teach this topic?_
+
+* A definition is a declaration that supplies all that is needed for a complete entity
+* `int baz = 42;`
+* `void bar() { /* implementation */ }`
+* `class Foo { /* class body */ };`
+
+### Topic introduction
+
+_Very brief introduction to the topic._
+
+A definition extends a declaration, providing all that is needed for a complete
+entity, e.g., allocate memory for variables, provide the implementation for
+functions, complete definitions of data and function members of a class.
+
+### Foundational: Defining variables and ODR {#def-found}
+
+
+#### Background/Required Knowledge
+
+
+A student:
+
+* is familiar with declarations [[C++ object model: declarations]][1]
+
+#### Student outcomes
+
+_A list of things "a student should be able to" after the curriculum._
+_The next word should be an action word and testable in an exam._
+_Max 5 items._
+
+A student should be able to:
+
+1. define a variable with a specific type `int baz = 42;`
+2. define a function `void bar() {}`
+3. define a class `class Foo {};`
+4. explain the one definition rule
+
+
+#### Caveats
+
+_This section mentions subtle points to understand, like anything resulting in
+implementation-defined, unspecified, or undefined behavior._
+
+No caveats at present.
+
+#### Points to cover
+
+_This section lists important details for each point._
+
+* One definition rule (ODR)
+
+### Main: Defining for programs {#def-main}
+
+
+#### Background/Required Knowledge
+
+
+* All of the above.
+* is familiar with declarations [[C++ object model: declarations]][1]
+
+#### Student outcomes
+
+_A list of things "a student should be able to" after the curriculum._
+_The next word should be an action word and testable in an exam._
+_Max 5 items._
+
+A student should be able to:
+
+1. organize variables, functions, classes into multiple translation units, describing interface with declarations and providing the implementations with definitions without violating ODR.
+2. distinguish between template declaration and definition
+
+#### Caveats
+
+_This section mentions subtle points to understand, like anything resulting in
+implementation-defined, unspecified, or undefined behavior._
+
+* Putting a definition into a header file that is included more than once leads to ODR violations, possibly resulting in linker errors. 
+
+#### Points to cover
+
+_This section lists important details for each point._
+
+### Advanced: Special cases and peculiarities {#def-advanced}
+
+_These are important topics that are not expected to be covered but provide
+guidance where one can continue to investigate this topic in more depth._
+
+* ABI Incompatibilities: Different definitions of the same type in multiple object files can lead to subtle program errors.
+
+[1]: ../object-model/declarations.md