Clarify whitespace handling

[cxw42]

• Section names can have trailing whitespace (the core tests expressly check this).
• When deciding what kind of line we have, all leading whitespace is ignored, and the trailing LF or CRLF is also ignored.
• Blank lines do not have to include whitespace.
• Fix some typos (change Markdown single-backticks to rst double-backticks).

Fixes https://github.com/editorconfig/editorconfig/issues/500

[Vampire]

Any news here? :-)

[florianb]

@cxw42 thanks for opening this - i got a question, so this to clarify that all empty lines (using only invisible characters) are ignored and all other lines should be interpreted after trimming (removing all invisible characters)?

I am asking this because i was confused if that is meant with "once leading whitespace is removed (and ignoring any trailing line separator".

[Vampire]

I'd say the only meaning changes here are, that blank lines may be empty when before they needed to have any whitespace, except if you consider the line separator part of the line. In the latter case I'd say all here is just using clearer words without semantic changes

[florianb]

Thanks @Vampire - i'm no native speaker so i wonder if the whole description is just difficult paraphrase of

• A EditorConfig file is consumed line by line
• Each line has to be trimmed before interpretation
• Empty lines should be ignored

[cxw42]

Thanks @Vampire for pointing out my confusion in the ticket.

@florianb I like the idea of specifing processing imperatively. I have just force-pushed a change that implements that idea. Thanks!

Let me know what you all think!

[Vampire]

I would re-add an explicit mentioning of empty lines. Currently it just says "if it not empty handle like type below". And below the list of line types it says "all other lines are invalid". So you can interpret this as "skip to the next line if a line is empty after the trim", but it would be open for interpretation again. I think if you explicitly say "if it is empty, ignore the line" there should be no room for interpretation in that regard.

[cxw42]

Updated!

• Re-added blank lines
• Fixed a typo I noticed
• Linked from the line types to relevant sections so that "process it this way" makes more sense.

Changes

$ git diff f4ebd49 5df4933
diff --git a/index.rst b/index.rst
index 2cf9e03..3ab63ce 100644
--- a/index.rst
+++ b/index.rst
@@ -79,18 +79,25 @@ EditorConfig files are in an INI-like file format.
 To read an EditorConfig file, take one line at a time.  For each line:
 
 #. Strip all leading and trailing whitespace
+#. If the remaining text is empty, ignore the line.
 #. If the remaining text is not empty, process the text as specified for its
    type below.
 
 The types of lines are:
 
-- Comment: starts with a ``;`` or a ``#``.
+- Comment: starts with a ``;`` or a ``#``.  Comment lines are ignored.
+
 - Section Header: starts with a ``[`` and ends with a ``]``.
+  These lines define globs; see :ref:`glob-expressions`.
+
    - May contain any characters between the square brackets (e.g.,
      ``[`` and ``]`` and even spaces and tabs are allowed).
    - Forward slashes (``/``) are used as path separators.
    - Backslashes (``\\``) are not allowed as path separators (even on Windows).
+
 - Key-Value Pair (or Pair): contains a key and a value, separated by an ``=``.
+  See :ref:`supported-pairs`.
+
    - Key: The part before the first ``=`` (trimmed of whitespace, but including
      any whitespace in the middle).
    - Value: The part after the first ``=`` (trimmed of whitespace, but including
@@ -119,7 +126,7 @@ This specification does not define any "escaping" mechanism for
 
 .. admonition :: Compatibility
 
-  The EditorConfig file format formerly allowed the use of ``;`` and ``;`` after the
+  The EditorConfig file format formerly allowed the use of ``;`` and ``#`` after the
   beginning of the line to mark the rest of a line as comment. This led to
   confusion how to parse values containing those characters. Old EditorConfig
   parsers may still allow inline comments.
@@ -135,6 +142,8 @@ The parts of an EditorConfig file are:
 - Section: the lines starting from a Section Header until the beginning of
   the next Section Header or the end of the file.
 
+.. _glob-expressions:
+
 Glob Expressions
 ================
 
@@ -187,6 +196,8 @@ precedence. If multiple EditorConfig files have matching sections, the rules
 from the closer EditorConfig file are read last, so pairs in closer
 files take precedence.
 
+.. _supported-pairs:
+
 Supported Pairs
 ===============