Merge pull request #3118 from apense/styledoc

Added Documentation Style Guide; Fixes #3089

2 files changed, 146 insertions, 4 deletions

diff --git a/contributing.rst b/contributing.rst
index 68b706c73..3b495f01f 100644
--- a/contributing.rst
+++ b/contributing.rst
@@ -142,7 +142,7 @@ When contributing new procedures, be sure to add documentation, especially if
 the procedure is exported from the module. Documentation begins on the line
 following the ``proc`` definition, and is prefixed by ``##`` on each line.
 
-Code examples are also encouraged. The RestructuredText Nim uses has a special 
+Code examples are also encouraged. The RestructuredText Nim uses has a special
 syntax for including examples.
 
 .. code-block:: nim
@@ -155,8 +155,8 @@ syntax for including examples.
     ##  echo someproc() # "something"
     result = "something" # single-hash comments do not produce documentation
 
-The ``.. code-block:: nim`` followed by a newline and an indentation instructs the 
-``nim doc`` and ``nim doc2`` commands to produce syntax-highlighted example code with 
+The ``.. code-block:: nim`` followed by a newline and an indentation instructs the
+``nim doc`` and ``nim doc2`` commands to produce syntax-highlighted example code with
 the documentation.
 
 When forward declaration is used, the documentation should be included with the
@@ -186,7 +186,7 @@ or
   proc hello*(): string =
     # says hello
     result = "hello"
-  
+
 the first is preferred.
 
 The Git stuff
@@ -216,3 +216,5 @@ General commit rules
       git diff --check --cached || exit $?
 
 3. Describe your commit and use your common sense.
+
+.. include:: styleguide.rst
diff --git a/docstyle.rst b/docstyle.rst
new file mode 100644
index 000000000..d789b1df9
--- /dev/null
+++ b/docstyle.rst
@@ -0,0 +1,140 @@
+Documentation Style
+===================
+
+General Guidelines
+------------------
+
+* Authors should document anything that is exported.
+* Within documentation, a period (`.`) should follow each sentence (or sentence fragment) in a comment block. The documentation may be limited to one sentence fragment, but if multiple sentences are within the documentation, each sentence after the first should be complete and in present tense.
+* Documentation is parsed as ReStructuredText (RST).
+* Inline code should be surrounded by double tick marks ("``````"). 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:
+
+.. code-block:: 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.
+
+.. code-block:: Nim
+
+  ## This is the best module ever. It provides answers to everything!
+  ##
+  ## :Author: Steve McQueen
+  ## :Copyright: 1965
+  ##
+
+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 (``````).
+
+.. code-block:: Nim
+
+  proc example1*(x: int) =
+    ## Prints the value of ``x``.
+    echo x
+
+Whenever an example of usage would be helpful to the user, you should include one within the documentation in RST format as below.
+
+.. code-block:: 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
+-----
+
+Exported types should also be documented. This documentation can also contain code samples, but those are better placed with the functions to which they refer.
+
+.. code-block:: Nim
+
+  type
+    NamedQueue*[T] = object ## Provides a linked data structure with names
+                            ## throughout. It is 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:
+
+.. code-block:: Nim
+
+  type
+    NamedQueue*[T] = object
+      ## Provides a linked data structure with names
+      ## throughout. It is 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.
+
+.. code-block:: Nim
+
+  type
+    ## This documentation disappears because it annotates the ``type`` keyword
+    ## above, not ``NamedQueue``.
+    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.
+
+.. code-block:: 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 and should therefore be prefaced by a single hash (``#``).
+
+.. code-block:: Nim
+
+  const
+    BadMathVals* = [
+      3.14, # pi
+      2.72, # e
+      0.58, # gamma
+    ] ## A bunch of badly rounded values.
+
+Nim supports Unicode in comments, so the above can be replaced with the following:
+
+.. code-block:: Nim
+
+  const
+    BadMathVals* = [
+      3.14, # π
+      2.72, # e
+      0.58, # γ
+    ] ## A bunch of badly rounded values (including π!).