Added Documentation Style Guide; Linked from contributing.rst

contributing.rst

@@ -216,3 +216,5 @@ General commit rules
       git diff --check --cached || exit $?
 
 3. Describe your commit and use your common sense.
+
+.. include:: styleguide.rst

styleguide.rst

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+Style Guide (Documentation)
+===========================
+
+General Guidelines
+------------------
+
+* Authors should document anything that is exported.
+* Within a documentation for a procedure, a period (`.`) should follow each sentence in a comment block if there is more than one sentence in that block; otherwise, no period should be used. In other sections, complete sentences should have periods. Sentence fragments should have none.
+* Documentation is parsed as RST (RestructuredText).
+* Inline code should be surrounded by double tick marks (``` `` ```). With ReStructuredTest (RST), if you would like a character to immediately follow inline code (e.g., "``int8``s are great!"), escape the following character with a backslash (`\`). The preceding is typed as ``` ``int8``\s are great!```.
+
+Module-level documentation
+--------------------------
+
+Documentation of a module is placed at the top of the module itself. Each line of documentation begins with double hashes (`##`).
+Code samples are encouraged, and should follow the general RST syntax:
+
+```nim
+## The ``universe`` module computes the answer to life, the universe, and everything.
+##
+## .. code-block:: nim
+##  echo computeAnswerString*() # "42"
+```
+
+Within this top-level comment, you can indicate the authorship and copyright of the code, which will be featured in the produced documentation.
+
+```nim
+## This is the best module ever. It provides answers to everything!
+##
+## :Author: Steve McQueen
+## :Copyright: 1965
+##
+```
+
+Users are encouraged to leave a space between the last line of top-level documentation and the beginning of Nim code (the imports, etc.).
+
+Procs, Templates, Macros, Converters, and Iterators
+---------------------------------------------------
+
+The documentation of a procedure should begin with a capital letter and should be in present tense. Variables referenced in the documentation should be surrounded by double tick marks (``` `` ```).
+
+```nim
+    proc example1*(x: int) =
+        ## Prints the value of ``x``
+        echo x
+```
+
+Whenever an example of usage would be helpful to the user, please include a sample within the documentation in RST format as below.
+
+```nim
+    proc addThree*(x, y, z: int8): int =
+        ## Adds three ``int8`` values, treating them as unsigned and
+        ## truncating the result
+        ##
+        ## .. code-block:: nim
+        ##  echo addThree(3, 125, 6) # -122
+        result = x +% y +% z
+```
+
+The commands ``nim doc`` and ``nim doc2`` will then correctly syntax highlight the Nim code within the documentation.
+
+Types
+-----
+
+Types should also be documented. This documentation can also contain code samples, but those are likely better placed with the functions to which they refer.
+
+```nim
+type
+  NamedQueue*[T] = object ## Provides a linked data structure with names
+                          ## throughout. Named for convenience. I'm making
+                          ## this comment long to show how you can, too.
+    name*: string ## The name of the item
+    val*: T ## Its value
+    next*: ref NamedQueue[T] ## The next item in the queue
+```
+
+You have some flexibility when placing the documentation:
+```nim
+type
+  NamedQueue*[T] = object
+    ## Provides a linked data structure with names
+    ## throughout. Named for convenience. I'm making
+    ## this comment long to show how you can, too.
+    name*: string ## The name of the item
+    val*: T ## Its value
+    next*: ref NamedQueue[T] ## The next item in the queue
+```
+
+Make sure to place the documentation beside or within the object.
+
+```nim
+type
+  ## This documentation disappears. It's basically annotating the
+  ## ``type`` above.
+  NamedQueue*[T] = object
+    name*: string ## This becomes the main documentation for the object, which
+                  ## is not what we want.
+    val*: T ## Its value
+    next*: ref NamedQueue[T] ## The next item in the queue
+
+```
+
+Var, Let, and Const
+-------------------
+
+When declaring module-wide constants and values, documentation is encouraged. The placement of doc comments is similar to the ``type`` sections.
+
+```nim
+const
+  X* = 42 ## An awesome number
+  SpreadArray* = [
+    [1,2,3],
+    [2,3,1],
+    [3,1,2],
+  ] ## Doc comment for ``SpreadArray``
+```
+
+Placement of comments in other areas is usually allowed, but will not become part of the documentation output.
+
+```nim
+const
+  BadMathVals* = [
+    3.14, ## pi
+    2.72, ## e
+    0.58, ## gamma
+  ] ## A bunch of badly rounded values
+```
+
+In the produced documentation, the comments beside the elements of ``BadMathVals`` do not make it into the final documentation.
+
+As a final note, Nim supports Unicode in comments just fine, so the above can be replaced with the following:
+
+```nim
+const
+  BadMathVals* = [
+    3.14, ## π
+    2.72, ## e
+    0.58, ## γ
+  ] ## A bunch of badly rounded values (including π!)
+```