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/// Internal namespace.
pub( crate ) mod private
{
// pub use winterval::exposed::*;
///
/// Result with syn::Error.
///
pub type Result< T > = std::result::Result< T, syn::Error >;
///
/// Macro for diagnostics purpose to print both syntax tree and source code behind it.
///
/// ### Sample
/// ```
/// use proc_macro_tools::prelude::*;
///
/// let code = qt!( std::collections::HashMap< i32, i32 > );
/// let tree_type = syn::parse2::< syn::Type >( code ).unwrap();
/// tree_print!( tree_type );
/// ```
///
#[ macro_export ]
// #[ macro_use ]
macro_rules! _tree_print
{
( $src:expr ) =>
{{
let result = $crate::tree_export_str!( $src );
println!( "{}", result );
result
}};
( $( $src:expr ),+ $(,)? ) =>
{{
$( $crate::tree_print!( $src ) );+
}};
}
///
/// Macro for diagnostics purpose to export both syntax tree and source code behind it into string.
///
#[ macro_export ]
// #[ macro_use ]
macro_rules! _tree_export_str
{
( $src:expr ) =>
{{
let src2 = &$src;
format!( "{} : {} :\n{:#?}", stringify!( $src ), $crate::qt!{ #src2 }, $src )
}};
}
///
/// Macro to generate syn error either with span of a syntax tree element or with default one `proc_macro2::Span::call_site()`.
///
/// ### Sample
/// ```
/// # use proc_macro_tools::*;
/// syn_err!( "No attr" );
/// # ()
/// ```
///
#[ macro_export ]
macro_rules! _syn_err
{
( $msg:expr $(,)? ) =>
{
syn::Error::new( proc_macro2::Span::call_site(), $msg )
};
( _, $msg:expr $(,)? ) =>
{
syn::Error::new( proc_macro2::Span::call_site(), $msg )
};
( $span:expr, $msg:expr $(,)? ) =>
{
syn::Error::new( syn::spanned::Spanned::span( &( $span ) ), $msg )
};
( $span:expr, $msg:expr, $( $arg:expr ),+ $(,)? ) =>
{
syn::Error::new( syn::spanned::Spanned::span( &( $span ) ), format!( $msg, $( $arg ),+ ) )
};
( _, $msg:expr, $( $arg:expr ),+ $(,)? ) =>
{
syn::Error::new( proc_macro2::Span::call_site(), format!( $msg, $( $arg ),+ ) )
};
}
/// Check is the rightmost item of path refering a type is specified type.
///
/// Good to verify `core::option::Option< i32 >` is optional.
/// Good to verify `alloc::vec::Vec< i32 >` is vector.
///
/// ### Sample
/// ```
/// use proc_macro_tools::*;
///
/// let code = qt!( core::option::Option< i32 > );
/// let tree_type = syn::parse2::< syn::Type >( code ).unwrap();
/// let got = type_rightmost( &tree_type );
/// assert_eq!( got, Some( "Option".to_string() ) );
/// ```
pub fn type_rightmost( ty : &syn::Type ) -> Option< String >
{
if let syn::Type::Path( path ) = ty
{
let last = &path.path.segments.last();
if last.is_none()
{
return None;
}
return Some( last.unwrap().ident.to_string() );
}
None
}
use winterval::*;
/// Return the specified number of parameters of the type.
///
/// Good to getting `i32` from `core::option::Option< i32 >` or `alloc::vec::Vec< i32 >`
///
/// ### Sample
/// ```
/// use proc_macro_tools::*;
///
/// let code = qt!( core::option::Option< i8, i16, i32, i64 > );
/// let tree_type = syn::parse2::< syn::Type >( code ).unwrap();
/// let got = type_parameters( &tree_type, 0..=2 );
/// got.iter().for_each( | e | println!( "{}", qt!( #e ) ) );
/// // < i8
/// // < i16
/// // < i32
/// ```
pub fn type_parameters< R >( ty : &syn::Type, range : R ) -> Vec< &syn::Type >
where
R : std::convert::Into< Interval >
{
let range = range.into();
if let syn::Type::Path( syn::TypePath{ path : syn::Path { ref segments, .. }, .. } ) = ty
{
let last = &segments.last();
if last.is_none()
{
return vec![ &ty ]
}
let args = &last.unwrap().arguments;
if let syn::PathArguments::AngleBracketed( ref args2 ) = args
{
let args3 = &args2.args;
let selected : Vec< &syn::Type > = args3
.iter()
.skip_while( | e | if let syn::GenericArgument::Type( _ ) = e { false } else { true } )
.skip( range.first().try_into().unwrap() )
.take( range.len().try_into().unwrap() )
.map( | e | if let syn::GenericArgument::Type( ty ) = e { ty } else { unreachable!( "Expects Type" ) } )
.collect();
return selected;
}
}
vec![ &ty ]
}
///
/// For attribute like `#[former( default = 31 )]` return key `default` and value `31`,
/// as well as syn::Meta as the last element of result tuple.
///
/// ### Sample
/// ``` ignore
/// let ( key, val, meta ) = attr_pair_single( &attr )?;
/// ```
pub fn attr_pair_single( attr : &syn::Attribute ) -> Result< ( String, syn::Lit, syn::Meta ) >
{
use syn::spanned::Spanned;
let meta = attr.parse_meta()?;
// zzz : try to use helper
let ( key, val );
match meta
{
syn::Meta::List( ref meta_list ) =>
match meta_list.nested.first()
{
Some( nested_meta ) => match nested_meta
{
syn::NestedMeta::Meta( meta2 ) => match meta2
{
syn::Meta::NameValue( name_value ) => // match &name_value.lit
{
if meta_list.nested.len() != 1
{
return Err( syn::Error::new( attr.span(), format!( "Expected single element of the list, but got {}", meta_list.nested.len() ) ) );
}
key = name_value.path.get_ident().unwrap().to_string();
val = name_value.lit.clone();
},
_ => return Err( syn::Error::new( attr.span(), "Unknown format of attribute, expected syn::Meta::NameValue( name_value )" ) ),
},
_ => return Err( syn::Error::new( attr.span(), "Unknown format of attribute, expected syn::NestedMeta::Meta( meta2 )" ) ),
},
_ => return Err( syn::Error::new( attr.span(), "Unknown format of attribute, expected Some( nested_meta )" ) ),
},
_ => return Err( syn::Error::new( attr.span(), "Unknown format of attribute, expected syn::Meta::List( meta_list )" ) ),
};
Ok( ( key, val, meta ) )
}
pub use _tree_print;
pub use _tree_export_str;
pub use _syn_err;
}
/// Exposed namespace of the module.
pub mod exposed
{
pub use super::prelude::*;
// use super::private as i;
pub use super::private::type_rightmost;
pub use super::private::type_parameters;
pub use super::private::attr_pair_single;
}
pub use exposed::*;
/// Prelude to use essentials: `use my_module::prelude::*`.
pub mod prelude
{
// use super::private as i;
pub use super::private::_tree_print as tree_print;
pub use super::private::_tree_export_str as tree_export_str;
pub use super::private::_syn_err as syn_err;
pub use super::private::Result;
}