started 0.5 folder, starting with p1 #1964

amitu · 2024-10-14T10:46:33Z

amitu
Oct 14, 2024
Maintainer

So I just started work on 0.5. As discussed in the past, this is almost going to be a complete rewrite.

The first bit we are going to handle is the fastn-p1::Section stuff. The earlier version was

Lines 21 to 31 in f72afd6

    
           pub struct Section { 
        
               pub name: String, 
        
               pub kind: Option<String>, 
        
               pub caption: Option<ftd_p1::Header>, 
        
               pub headers: ftd_p1::Headers, 
        
               pub body: Option<Body>, 
        
               pub sub_sections: Vec<Section>, 
        
               pub is_commented: bool, 
        
               pub line_number: usize, 
        
               pub block_body: bool, 
        
           }

.

And I have created:

fastn/v0.5/p1/src/lib.rs

Lines 3 to 11 in 971294b

    
           pub struct Section<'a> { 
        
               // this is the comment block we encountered before the section 
        
               // pub pre_comment: Option<Sourced<&'a str>>, 
        
               pub name: KindedName<'a>, 
        
               pub caption: Option<HeaderValue<'a>>, 
        
               pub headers: Vec<(KindedName<'a>, HeaderValue<'a>)>, 
        
               pub body: Option<Sourced<HeaderValue<'a>>>, 
        
               pub sub_sections: Vec<Section<'a>>, 
        
           }

Important thing to note is that we are going to use std::borrow::Cow, instead of cloning. Till now we cloned every string, but this time we are going to keep references. Things that will not be modified, e.g., the name of a Section, can be just a slice into the original source string. But things that can be modified, e.g. the caption where we handle escaped {} etc, will have to be Copied:

-- foo: \$x \{ yo \}

Should be:

Section { 
    name: KindedName { 
        kind: None, 
        name: Sourced { 
            from: 3,
            to: 5,
            is_commented: false,
            value: "foo" // this is slice into original string instead of a new String
        },
        caption: Some(
              vec![
                  Sourced { // from / to omitted
                        value: StringOrSection::String(Cow::Owned("\$x { yo }")
                  }
              ]
        )
        ..Default::default()
}

Note that p1 parse does not know about $x yet, so it was not extracted, but it understands the {}, so \{ yo \} was converted to { yo }.

The main problem I see here is the handling of comments. I considered adding these:

pub struct Section<'a> {
    // this is the comment block we encountered before the section
    pub pre_comment: Option<Sourced<&'a str>>,
    pub name: KindedName<'a>,
    pub caption: Option<HeaderValue<'a>>,
    pub headers: Vec<(KindedName<'a>, HeaderValue<'a>)>,
    pub pre_body_comment: Option<Sourced<&'a str>>,
    pub body: Option<Sourced<HeaderValue<'a>>>,
    pub post_body_comment: Option<Sourced<&'a str>>,
    pub sub_sections: Vec<Section<'a>>,
}

This has some problems. One is pre_comment for only the first section would be populated, for every other second the post_body_comment will eat up the comments till next section. We can not drop post_body_comment, as what will happen to the comment after the body of the last section?

Also how will we store per comment, eg comment in each header etc?

Also currently we have only two forms of comment, entire line is comment, or part of line after the ;; is comment. We do not have inline comment, eg -- {- this is comment -} foo: {- some more comment -} the real caption. We do not yet have such inline comment in the spec, and not sure if we should add them. They do help, most languages have them, so saying we will not have them is not great long term solution.

amitu · 2024-10-14T11:06:38Z

amitu
Oct 14, 2024
Maintainer Author

Why are we bothering with capturing comments in this type? Can we not pre-process and exclude the comments? But then how will we handle fastn fmt. fastn fmt has to have access to all comments, and I was thinking this fastn_p1::Section type can be used as input for fastn_fmt function. Like to make this fastn_p1::Section the main object we share.

We have another option of creating a more low level type, or keeping fastn_p1::Section as that low level type and move this one to fastn_p2::Section, which does not contain comments. So we have p1 and p2 versions.

Other option is to keep all comments in a separate data structure, so our parse returns (Vec<fastn_p1::Section>, Vec<fastn_p1::Comment>), and we do a sort of "CodeMorror::map" equivalent helper, which when feed a change in fastn_p1::Section (e.g. every time we move a position, the corresponding positions in Vec<fastn_p1::Comment> positions are updated.

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started 0.5 folder, starting with p1 #1964

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started 0.5 folder, starting with p1 #1964

amitu Oct 14, 2024 Maintainer

Replies: 1 comment

amitu Oct 14, 2024 Maintainer Author

amitu
Oct 14, 2024
Maintainer

amitu
Oct 14, 2024
Maintainer Author