willbe 0.35.0

#[ allow( clippy ::std_instead_of_alloc, clippy ::std_instead_of_core ) ]
mod private
{

  use crate :: *;
  // qqq: for Bohdan: bad
  // use std :: *;
  use std ::slice;
  use former ::Former;

  /// Stores information about the current workspace.
  #[ derive( Debug, Clone ) ]
  pub struct Workspace
  {
  /// Metadata of the workspace, containing detailed information about the packages, dependencies, and other workspace-related data.
  pub metadata: cargo_metadata ::Metadata,
  /// The directory containing the manifest file (`Cargo.toml`) of the workspace.
  pub crate_dir: CrateDir,
 }

  /// Represents errors related to workspace operations.
  #[ derive( Debug, error ::typed ::Error ) ]
  pub enum WorkspaceInitError
  {
  /// Something went wrong with path to a workspace.
  #[ error( "Path error. Details: {0}" ) ]
  Path( #[ from ] PathError ),
  /// Something went wrong with the workspace' data
  #[ error( "Can not load workspace data. Details: {0}" ) ]
  Metadata( #[ from ] cargo_metadata ::Error ),
  /// Files error
  #[ error( "I/O error: {0}" ) ]
  IO( #[ from ] std ::io ::Error ),
 }

  impl TryFrom< CrateDir > for Workspace
  {
  type Error = WorkspaceInitError;

  /// Load data from current directory
  fn try_from( mut crate_dir: CrateDir ) -> Result< Self, Self ::Error >
  {
   let metadata = cargo_metadata ::MetadataCommand ::new()
   .current_dir( crate_dir.as_ref() )
   .no_deps()
   .exec()?;
   // inout crate dir may refer on crate's manifest dir, not workspace's manifest dir
   crate_dir = ( &metadata.workspace_root ).try_into()?;
   Result ::Ok( Self
   {
  metadata,
  crate_dir,
 })
 }

 }

  impl TryFrom< CurrentPath > for Workspace
  {
  type Error = WorkspaceInitError;

  /// Load data from current directory
  fn try_from( _cd: CurrentPath ) -> Result< Self, Self ::Error >
  {
   let abs_path = AbsolutePath ::try_from( std ::env ::current_dir()? )?;
   let crate_dir = CrateDir ::try_from( abs_path )?;
   Self ::try_from( crate_dir )
 }

 }

  impl From< cargo_metadata ::Metadata > for Workspace
  {
  fn from( metadata: cargo_metadata ::Metadata ) -> Self
  {
   // SAFE: `workspace_root` is a path to a`Cargo.toml` file, therefor the parent is the directory
   let path = metadata.workspace_root.as_std_path().parent().unwrap().to_path_buf();
   let crate_dir = CrateDir ::try_from( path ).unwrap();
   Self
   {
  metadata,
  crate_dir,
 }
 }
 }

  impl Workspace
  {

  /// Returns list of all packages
  pub fn packages< 'a >( &'a self )
  -> core ::iter ::Map
  <
   slice ::Iter< 'a, cargo_metadata ::Package >,
   impl Fn( &'a cargo_metadata ::Package ) -> WorkspacePackageRef< 'a > + Clone,
 >
  {
   self.metadata.packages.iter().map( WorkspacePackageRef ::from )
 }

  /// Returns the path to workspace root
  ///
  /// # Panics
  /// qqq: doc
  #[ must_use ]
  pub fn workspace_root( &self ) -> CrateDir
  {
   // Safe because workspace_root.as_std_path() is always a path to a directory
   CrateDir ::try_from( self.metadata.workspace_root.as_std_path() ).unwrap()
 }

  /// Returns the path to target directory
  #[ must_use ]
  pub fn target_directory( &self ) -> &std ::path ::Path
  {
   self.metadata.target_directory.as_std_path()
 }

  /// Find a package by its manifest file path
  ///
  /// # Panics
  /// qqq: doc
  pub fn package_find_by_manifest< P >( &self, manifest_file: P ) -> Option< WorkspacePackageRef< '_ > >
  where
   P: AsRef< std ::path ::Path >,
  {
   self
   .packages()
   .find( | &p | p.manifest_file().unwrap().as_ref() == manifest_file.as_ref() )
 }

  /// Filter of packages.
  #[ must_use ]
  pub fn packages_which( &self ) -> PackagesFilterFormer< '_ >
  {
   // PackagesFilter ::new( self )
   PackagesFilter ::former().workspace( self )
 }

 }


  #[ derive( Former ) ]
  // #[ debug ]
  #[ allow( missing_debug_implementations ) ]
  pub struct PackagesFilter< 'a >
  {
  workspace: &'a Workspace,
  crate_dir: Box< dyn PackageFilter >,
  manifest_file: Box< dyn PackageFilter >,
 }

  pub trait PackageFilter
  {
  fn include( &self, package: WorkspacePackageRef< '_ > ) -> bool;
 }

  impl Default for Box< dyn PackageFilter >
  {
  fn default() -> Self
  {
   Box ::new( PackageFilterAll )
 }
 }

  pub struct PackageFilterAll;
  impl PackageFilter for PackageFilterAll
  {
  #[ inline( always ) ]
  fn include( &self, _package: WorkspacePackageRef< '_ > ) -> bool
  {
   true
 }
 }

  pub struct PackageFilterCrateDir( CrateDir );
  impl PackageFilter for PackageFilterCrateDir
  {
  #[ inline( always ) ]
  fn include( &self, package: WorkspacePackageRef< '_ > ) -> bool
  {
   self.0 == package.crate_dir().unwrap()
 }
 }

  impl From< CrateDir > for Box< dyn PackageFilter >
  {
  #[ inline( always ) ]
  fn from( src: CrateDir ) -> Self
  {
   Box ::new( PackageFilterCrateDir( src ) )
 }
 }

  pub struct PackageFilterManifestFile( ManifestFile );
  impl PackageFilter for PackageFilterManifestFile
  {
  #[ inline( always ) ]
  fn include( &self, package: WorkspacePackageRef< '_ > ) -> bool
  {
   self.0 == package.manifest_file().unwrap()
 }
 }

  impl From< ManifestFile > for Box< dyn PackageFilter >
  {
  #[ inline( always ) ]
  fn from( src: ManifestFile ) -> Self
  {
   Box ::new( PackageFilterManifestFile( src ) )
 }
 }

  impl< 'a > PackagesFilter< 'a >
  {

  pub fn new( workspace: &'a Workspace ) -> Self
  {
   Self
   {
  workspace,
  crate_dir: Box ::default(),
  manifest_file: Box ::default(),
 }
 }

  #[ inline( always ) ]
  #[ allow( clippy ::unused_self ) ]
  pub fn iter( &'a self ) -> impl Iterator< Item = WorkspacePackageRef< 'a > > + Clone
  {

   // self
   // .workspace
   // .packages()
   // .find( | &p | p.manifest_file().unwrap().as_ref() == manifest_file.as_ref() )

   // let filter_crate_dir = if Some( crate_dir ) = self.crate_dir
   // {
   //   | p | p.manifest_file().unwrap().as_ref() == manifest_file.as_ref()
   // }

   std ::iter ::empty()
 }

 }

  impl< 'a > PackagesFilterFormer< 'a >
  {
  #[ inline( always ) ]
  // pub fn find< 'a >( self ) -> impl Iterator< Item = WorkspacePackageRef< 'a > > + Clone
  pub fn find( self ) -> Option< WorkspacePackageRef< 'a > >
  {
   let formed = self.form();

   formed
   .workspace
   .packages()
   .find( | &p |
   {
  if !formed.crate_dir.include( p ) { return false }
  if !formed.manifest_file.include( p ) { return false }
  true
 })
   // .unwrap()

   // let filter_crate_dir = if Some( crate_dir ) = self.crate_dir
   // {
   //   | p | p.manifest_file().unwrap().as_ref() == manifest_file.as_ref()
   // }

   // std ::iter ::empty()
 }
 }

  impl Entries for Workspace
  {
  fn entries( &self ) -> impl IterTrait< '_, SourceFile >
  {
   self
   .packages()
   .flat_map( | package | package.entries().collect :: < Vec< _ > >() )
   .collect :: < Vec< _ > >()
   .into_iter()
 }
 }

  impl Sources for Workspace
  {
  fn sources( &self ) -> impl IterTrait< '_, SourceFile >
  {
   self
   .packages()
   .flat_map( | package | package.sources().collect :: < Vec< _ > >() )
   .collect :: < Vec< _ > >().into_iter()
   // .into_iter()
 }
 }

}

//

crate ::mod_interface!
{
  exposed use WorkspaceInitError;
  exposed use Workspace;
}