hush 0.1.4

Hush is a unix shell scripting language based on the Lua programming language
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mod fmt;

use super::{SourcePos, Token, TokenKind};


/// The kind of token the parser was expecting.
#[derive(Debug)]
pub enum Expected {
	Token(TokenKind),
	Message(&'static str),
}


/// A parser error.
#[derive(Debug)]
pub enum Error {
	/// Premature EOF.
	UnexpectedEof,
	/// Unexpected token.
	Unexpected { token: Token, expected: Expected },
	/// Command blocks must have at least one command.
	EmptyCommandBlock { pos: SourcePos },
	/// Invalid env-assign. This is a spurious error while parsing, and should be handled
	/// internally.
	InvalidEnvAssign,
}


impl Error {
	/// Create an error signaling unexpected EOF.
	pub fn unexpected_eof() -> Self {
		Self::UnexpectedEof
	}


	/// Create an error signaling an unexpected token, and what was expected.
	pub fn unexpected(token: Token, expected: TokenKind) -> Self {
		Self::Unexpected { token, expected: Expected::Token(expected) }
	}


	/// Create an error signaling an unexpected token, and a message.
	pub fn unexpected_msg(token: Token, message: &'static str) -> Self {
		Self::Unexpected { token, expected: Expected::Message(message) }
	}


	/// Create an error signaling a command block is empty.
	pub fn empty_command_block(pos: SourcePos) -> Self {
		Self::EmptyCommandBlock { pos }
	}
}


impl std::error::Error for Error {}