///
/// Alias for std::error::BasicError.
///

pub use std::error::Error as ErrorInterface;

///
/// Macro to generate error.
///
/// ### Sample
/// ```
/// # use error_tools::*;
/// err!( "No attr" );
/// ```
///

#[ macro_export ]
macro_rules! err
{

  ( $msg : expr ) =>
  {
    $crate::BasicError::new( $msg )
  };
  ( $msg : expr, $( $arg : expr ),+ ) =>
  {
    $crate::BasicError::new( format!( $msg, $( $arg ),+ ) )
  };

}

/// baic implementation of generic BasicError

#[ derive( core::fmt::Debug, core::clone::Clone, core::cmp::PartialEq ) ]
pub struct BasicError
{
  msg : String,
}

impl BasicError
{
  /// Constructor expecting message with description.
  pub fn new< Msg : Into< String > >( msg : Msg ) -> BasicError
  {
    BasicError { msg : msg.into() }
  }
  /// Message with description getter.
  pub fn msg( &self ) -> &String
  {
    &self.msg
  }
}

impl core::fmt::Display for BasicError
{
  fn fmt(&self, f: &mut core::fmt::Formatter< '_ >) -> core::fmt::Result
  {
    write!( f, "{}", self.msg )
  }
}

impl ErrorInterface for BasicError
{
  fn description( &self ) -> &str
  {
    &self.msg
  }
}

// qqq : write standard mod interface without using mod_interface