Skip to content

Commit

Permalink
Merge pull request #1349 from YBoy-git/match_attributes
Browse files Browse the repository at this point in the history 
READY : Match attributes
  • Loading branch information
@Wandalen
Wandalen committed May 21, 2024
2 parents 4aa8ce8 + 1acc833 commit f28ed54
Show file tree
Hide file tree
Showing 3 changed files with 211 additions and 202 deletions.
341 changes: 172 additions & 169 deletions module/core/derive_tools_meta/src/derive/from.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -353,172 +353,175 @@ fn generate_unit

// xxx2 : get completed

// ///
// /// Attributes of a field / variant
// ///
//
// pub struct FieldAttributes
// {
// pub from : Option< AttributeFrom >,
// }
//
// impl FieldAttributes
// {
//
// pub fn from_attrs< 'a >( attrs : impl Iterator< Item = &'a syn::Attribute > ) -> Result< Self >
// {
// let mut from : AttributeFrom = None;
//
// for attr in attrs
// {
// let key_ident = attr.path().get_ident()
// .ok_or_else( || syn_err!( attr, "Expects an attribute of format #[ attribute( val ) ], but got:\n {}", qt!{ #attr } ) )?;
// let key_str = format!( "{}", key_ident );
//
// if attr::is_standard( &key_str )
// {
// continue;
// }
//
// // qqq : qqq for Anton : xxx : refactor field_attrs::FieldAttributes::from_attrs to make it similar to this function
// match key_str.as_ref()
// {
// AttributeFrom::KEYWORD =>
// {
// from.replace( AttributeFrom::from_meta( attr )? );
// }
// "debug" =>
// {
// }
// _ =>
// {
// return Err( syn_err!( attr, "Known field attirbutes are : `from`, `debug`.\nUnknown structure attribute : {}", qt!{ #attr } ) );
// }
// }
// }
//
// Ok( FieldAttributes { from } )
// }
//
// }
//
//
// ///
// /// Attribute to hold parameters of forming for a specific field or variant.
// /// For example to avoid code From generation for it.
// ///
// /// `#[ from( off, hint : true ) ]`
// ///
//
// pub struct AttributeFrom
// {
// /// Explicitly enable generation of From for a specific field/variant.
// /// By default From is generated, but at some circumstances it's required to opt in explicitly.
// pub on : Option< syn::Ident >,
// /// Disable generation of From for a specific field/variant.
// pub off : Option< syn::Ident >,
// /// Specifies whether to provide a sketch of generated From or not.
// /// Defaults to `false`, which means no hint is provided unless explicitly requested.
// pub hint : bool,
// }
//
// impl AttributeFrom
// {
//
// const KEYWORD : &'static str = "from";
//
// pub fn from_meta( attr : &syn::Attribute ) -> Result< Self >
// {
// match attr.meta
// {
// syn::Meta::List( ref meta_list ) =>
// {
// return syn::parse2::< AttributeFrom >( meta_list.tokens.clone() );
// },
// syn::Meta::Path( ref _path ) =>
// {
// return Ok( Default::default() )
// },
// _ => return_syn_err!( attr, "Expects an attribute of format #[ from( off ) ]
// .\nGot: {}", qt!{ #attr } ),
// }
// }
//
// }
//
// impl syn::parse::Parse for AttributeFrom
// {
// fn parse( input : syn::parse::ParseStream< '_ > ) -> syn::Result< Self >
// {
// let mut off : bool = false;
// let mut on : bool = false;
// let mut hint = false;
//
// while !input.is_empty()
// {
// let lookahead = input.lookahead1();
// if lookahead.peek( syn::Ident )
// {
// let ident : syn::Ident = input.parse()?;
// // xxx : qqq for Anton : use match here and for all attributes
// if ident == "off"
// {
// input.parse::< syn::Token![ = ] >()?;
// let value : syn::LitBool = input.parse()?;
// off = value.value();
// }
// else if ident == "on"
// {
// input.parse::< syn::Token![ = ] >()?;
// let value : syn::LitBool = input.parse()?;
// on = value.value();
// }
// else if ident == "hint"
// {
// input.parse::< syn::Token![ = ] >()?;
// let value : syn::LitBool = input.parse()?;
// hint = value.value;
// }
// else
// {
// return Err( syn::Error::new_spanned( &ident, format!( "Unexpected identifier '{}'. Expected 'on', 'off', or 'hint'. For example: `#[ from( off, hint : true ) ]`", ident ) ) );
// }
// }
// else
// {
// return Err( syn::Error::new( input.span(), "Unexpected identifier '{}'. Expected 'on', 'off', or 'hint'. For example: `#[ from( off, hint : true ) ]`" ) );
// }
//
// }
//
// // xxx : move on / off logic into a helper
//
// let mut enabled : Option< bool >;
//
// if on && off
// {
// return Err( syn_err!( input, "`on` and `off` are mutually exclusive .\nIllegal attribute usage : {}", qt!{ #input } ) )
// // xxx : test
// }
//
// if !on && !off
// {
// enabled = None;
// }
// else if on
// {
// enabled = Some( true )
// }
// else if off
// {
// enabled = Some( false )
// }
//
// // Optional comma handling
// if input.peek( syn::Token![,] )
// {
// input.parse::< syn::Token![,] >()?;
// }
// Ok( Self { enabled, hint } )
// }
// }
///
/// Attributes of a field / variant
///

pub struct FieldAttributes
{
pub from : Option< AttributeFrom >,
}

impl FieldAttributes
{

pub fn from_attrs< 'a >( attrs : impl Iterator< Item = &'a syn::Attribute > ) -> Result< Self >
{
let mut from : Option< AttributeFrom > = None;

for attr in attrs
{
let key_ident = attr.path().get_ident()
.ok_or_else( || syn_err!( attr, "Expects an attribute of format #[ attribute( val ) ], but got:\n {}", qt!{ #attr } ) )?;
let key_str = format!( "{}", key_ident );

if attr::is_standard( &key_str )
{
continue;
}

// qqq : qqq for Anton : xxx : refactor field_attrs::FieldAttributes::from_attrs to make it similar to this function
match key_str.as_ref()
{
AttributeFrom::KEYWORD =>
{
from.replace( AttributeFrom::from_meta( attr )? );
}
"debug" =>
{
}
_ =>
{
return Err( syn_err!( attr, "Known field attirbutes are : `from`, `debug`.\nUnknown structure attribute : {}", qt!{ #attr } ) );
}
}
}

Ok( FieldAttributes { from } )
}

}


///
/// Attribute to hold parameters of forming for a specific field or variant.
/// For example to avoid code From generation for it.
///
/// `#[ from( off, hint : true ) ]`
///

#[ derive( Default ) ]
pub struct AttributeFrom
{
/// Specifies whether we should generate From implementation for the field.
/// Can be altered using `on` and `off` attributes
pub enabled : Option< bool >,
/// Specifies whether to provide a sketch of generated From or not.
/// Defaults to `false`, which means no hint is provided unless explicitly requested.
pub hint : bool,
}

impl AttributeFrom
{

const KEYWORD : &'static str = "from";

pub fn from_meta( attr : &syn::Attribute ) -> Result< Self >
{
match attr.meta
{
syn::Meta::List( ref meta_list ) =>
{
return syn::parse2::< AttributeFrom >( meta_list.tokens.clone() );
},
syn::Meta::Path( ref _path ) =>
{
return Ok( Default::default() )
},
_ => return_syn_err!( attr, "Expects an attribute of format #[ from( off ) ]
.\nGot: {}", qt!{ #attr } ),
}
}

}

impl syn::parse::Parse for AttributeFrom
{
fn parse( input : syn::parse::ParseStream< '_ > ) -> syn::Result< Self >
{
let mut off : bool = false;
let mut on : bool = false;
let mut hint = false;

while !input.is_empty()
{
let lookahead = input.lookahead1();
if lookahead.peek( syn::Ident )
{
let ident : syn::Ident = input.parse()?;
// xxx : qqq for Anton : use match here and for all attributes -- done
match ident.to_string().as_str()
{
"off" =>
{
input.parse::< syn::Token![ = ] >()?;
let value : syn::LitBool = input.parse()?;
off = value.value();
},
"on" =>
{
input.parse::< syn::Token![ = ] >()?;
let value : syn::LitBool = input.parse()?;
on = value.value();
}
"hint" =>
{
input.parse::< syn::Token![ = ] >()?;
let value : syn::LitBool = input.parse()?;
hint = value.value;
}
_ =>
{
return Err( syn::Error::new_spanned( &ident, format!( "Unexpected identifier '{}'. Expected 'on', 'off', or 'hint'. For example: `#[ from( off, hint : true ) ]`", ident ) ) );
}
}
}
else
{
return Err( syn::Error::new( input.span(), "Unexpected identifier '{}'. Expected 'on', 'off', or 'hint'. For example: `#[ from( off, hint : true ) ]`" ) );
}

}

// xxx : move on / off logic into a helper

let mut enabled : Option< bool > = None;

if on && off
{
// return Err( syn_err!( input, "`on` and `off` are mutually exclusive .\nIllegal attribute usage : {}", qt!{ #input } ) )
return Err( syn::Error::new( input.span(), "`on` and `off` are mutually exclusive .\nIllegal attribute usage" ) );
// xxx : test
}

if !on && !off
{
enabled = None;
}
else if on
{
enabled = Some( true )
}
else if off
{
enabled = Some( false )
}

// Optional comma handling
if input.peek( syn::Token![,] )
{
input.parse::< syn::Token![,] >()?;
}
Ok( Self { enabled, hint } )
}
}
Loading

0 comments on commit f28ed54

Please sign in to comment.