Re: [PATCH 08/20] qapi/parser: differentiate intro and outro paragraphs

[Markus Armbruster <armbru@redhat.com>]

John Snow <jsnow@redhat.com> writes:

> Add a semantic tag to paragraphs that appear *before* tagged
> sections/members/features and those that appear after. This will control
> how they are inlined when doc sections are merged and flattened.

This future use is not obvious to me now.  I guess the effective way to
help me see it is actual patches, which will come in due time.

> Signed-off-by: John Snow <jsnow@redhat.com>
> ---
>  scripts/qapi/parser.py | 22 +++++++++++++++++-----
>  1 file changed, 17 insertions(+), 5 deletions(-)
>
> diff --git a/scripts/qapi/parser.py b/scripts/qapi/parser.py
> index cf4cbca1c1f..b1794f71e12 100644
> --- a/scripts/qapi/parser.py
> +++ b/scripts/qapi/parser.py
> @@ -503,6 +503,10 @@ def get_doc(self) -> 'QAPIDoc':
>              self.accept(False)
>              line = self.get_doc_line()
>              no_more_args = False
> +            # Paragraphs before members/features/tagged are "intro" paragraphs.
> +            # Any appearing subsequently are "outro" paragraphs.
> +            # This is only semantic metadata for the doc generator.

Not sure about the last sentence.  Isn't it true for almost everything
around here?

Also, long line.  

> +            intro = True
>  
>              while line is not None:
>                  # Blank lines
> @@ -532,6 +536,7 @@ def get_doc(self) -> 'QAPIDoc':
>                          raise QAPIParseError(
>                              self, 'feature descriptions expected')
>                      no_more_args = True
> +                    intro = False

After feature descriptions.

>                  elif match := self._match_at_name_colon(line):
>                      # description
>                      if no_more_args:
> @@ -547,6 +552,7 @@ def get_doc(self) -> 'QAPIDoc':
>                              doc.append_line(text)
>                          line = self.get_doc_indented(doc)
>                      no_more_args = True
> +                    intro = False

Or after member descriptions.

>                  elif match := re.match(
>                          r'(Returns|Errors|Since|Notes?|Examples?|TODO): *',
>                          line):
> @@ -557,13 +563,14 @@ def get_doc(self) -> 'QAPIDoc':
>                          doc.append_line(text)
>                      line = self.get_doc_indented(doc)
>                      no_more_args = True
> +                    intro = False

Or after the first tagged section.

Okay, it does what it says on the tin.

>                  elif line.startswith('='):
>                      raise QAPIParseError(
>                          self,
>                          "unexpected '=' markup in definition documentation")
>                  else:
>                      # tag-less paragraph
> -                    doc.ensure_untagged_section(self.info)
> +                    doc.ensure_untagged_section(self.info, intro)
>                      doc.append_line(line)
>                      line = self.get_doc_paragraph(doc)
>          else:
> @@ -617,7 +624,7 @@ def __init__(
>              self,
>              info: QAPISourceInfo,
>              tag: Optional[str] = None,
> -            kind: str = 'paragraph',
> +            kind: str = 'intro-paragraph',

The question "why is this optional?" crossed my mind when reviewing the
previous patch.  I left it unasked, because I felt challenging the
overlap between @kind and @tag was more useful.  However, the new
default value 'intro-paragraph' feels more arbitrary to me than the old
one 'paragraph', and that makes the question pop right back into my
mind.

Unless I'm mistaken, all calls but one @tag and @kind.  Making that one
pass it too feels simpler to me.

Moot if we fuse @tag and @kind, of course.

>          ):
>              # section source info, i.e. where it begins
>              self.info = info
> @@ -625,7 +632,7 @@ def __init__(
>              self.tag = tag
>              # section text without tag
>              self.text = ''
> -            # section type - {paragraph, feature, member, tagged}
> +            # section type - {<intro|outro>-paragraph, feature, member, tagged}

Long line.

>              self.kind = kind
>  
>          def append_line(self, line: str) -> None:
> @@ -666,7 +673,11 @@ def end(self) -> None:
>                  raise QAPISemError(
>                      section.info, "text required after '%s:'" % section.tag)
>  
> -    def ensure_untagged_section(self, info: QAPISourceInfo) -> None:
> +    def ensure_untagged_section(
> +        self,
> +        info: QAPISourceInfo,
> +        intro: bool = True,

Two callers, one passes @info, one doesn't.  Passing it always might be
simpler.

> +    ) -> None:
>          if self.all_sections and not self.all_sections[-1].tag:
>              section = self.all_sections[-1]
>              # Section is empty so far; update info to start *here*.
> @@ -677,7 +688,8 @@ def ensure_untagged_section(self, info: QAPISourceInfo) -> None:
>                  self.all_sections[-1].text += '\n'
>              return
>          # start new section
> -        section = self.Section(info)
> +        kind = ("intro" if intro else "outro") + "-paragraph"
> +        section = self.Section(info, kind=kind)
>          self.sections.append(section)
>          self.all_sections.append(section)