yash-syntax 0.19.0

// This file is part of yash, an extended POSIX shell.
// Copyright (C) 2020 WATANABE Yuki
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

//! Syntax parser for command
//!
//! Note that the detail parser for each type of commands is in another
//! dedicated module.

use super::core::Parser;
use super::core::Rec;
use super::core::Result;
use super::lex::Keyword::{Function, OpenBracketBracket};
use super::lex::TokenId::Token;
use super::{Error, SyntaxError};
use crate::syntax::Command;

impl Parser<'_, '_> {
    /// Parses a command.
    ///
    /// If there is no valid command at the current position, this function
    /// returns `Ok(Rec::Parsed(None))`.
    pub async fn command(&mut self) -> Result<Rec<Option<Command>>> {
        match self.simple_command().await? {
            Rec::AliasSubstituted => Ok(Rec::AliasSubstituted),

            Rec::Parsed(None) => {
                if let Some(compound) = self.full_compound_command().await? {
                    return Ok(Rec::Parsed(Some(Command::Compound(compound))));
                }

                let next = self.peek_token().await?;
                match next.id {
                    Token(Some(Function)) => {
                        let cause = SyntaxError::UnsupportedFunctionDefinitionSyntax.into();
                        let location = next.word.location.clone();
                        Err(Error { cause, location })
                    }
                    Token(Some(OpenBracketBracket)) => {
                        let cause = SyntaxError::UnsupportedDoubleBracketCommand.into();
                        let location = next.word.location.clone();
                        Err(Error { cause, location })
                    }
                    _ => Ok(Rec::Parsed(None)),
                }
            }

            Rec::Parsed(Some(c)) => self
                .short_function_definition(c)
                .await
                .map(|c| Rec::Parsed(Some(c))),
        }
    }
}

#[cfg(test)]
mod tests {
    use super::super::ErrorCause;
    use super::super::lex::Lexer;
    use super::super::lex::TokenId::EndOfInput;
    use super::*;
    use crate::source::Source;
    use assert_matches::assert_matches;
    use futures_util::FutureExt as _;

    #[test]
    fn parser_command_simple() {
        let mut lexer = Lexer::with_code("foo < bar");
        let mut parser = Parser::new(&mut lexer);

        let result = parser.command().now_or_never().unwrap();
        let command = result.unwrap().unwrap().unwrap();
        assert_matches!(command, Command::Simple(c) => {
            assert_eq!(c.to_string(), "foo <bar");
        });

        let next = parser.peek_token().now_or_never().unwrap().unwrap();
        assert_eq!(next.id, EndOfInput);
    }

    #[test]
    fn parser_command_compound() {
        let mut lexer = Lexer::with_code("(foo) < bar");
        let mut parser = Parser::new(&mut lexer);

        let result = parser.command().now_or_never().unwrap();
        let command = result.unwrap().unwrap().unwrap();
        assert_matches!(command, Command::Compound(c) => {
            assert_eq!(c.to_string(), "(foo) <bar");
        });

        let next = parser.peek_token().now_or_never().unwrap().unwrap();
        assert_eq!(next.id, EndOfInput);
    }

    #[test]
    fn parser_command_short_function() {
        let mut lexer = Lexer::with_code("fun () ( echo )");
        let mut parser = Parser::new(&mut lexer);

        let result = parser.command().now_or_never().unwrap();
        let command = result.unwrap().unwrap().unwrap();
        assert_matches!(command, Command::Function(f) => {
            assert_eq!(f.to_string(), "fun() (echo)");
        });

        let next = parser.peek_token().now_or_never().unwrap().unwrap();
        assert_eq!(next.id, EndOfInput);
    }

    #[test]
    fn parser_command_long_function() {
        let mut lexer = Lexer::with_code("  function fun { echo; }");
        let mut parser = Parser::new(&mut lexer);

        let e = parser.command().now_or_never().unwrap().unwrap_err();
        assert_eq!(
            e.cause,
            ErrorCause::Syntax(SyntaxError::UnsupportedFunctionDefinitionSyntax)
        );
        assert_eq!(*e.location.code.value.borrow(), "  function fun { echo; }");
        assert_eq!(e.location.code.start_line_number.get(), 1);
        assert_eq!(*e.location.code.source, Source::Unknown);
        assert_eq!(e.location.range, 2..10);
    }

    #[test]
    fn parser_command_double_bracket() {
        let mut lexer = Lexer::with_code(" [[ foo ]]");
        let mut parser = Parser::new(&mut lexer);

        let e = parser.command().now_or_never().unwrap().unwrap_err();
        assert_eq!(
            e.cause,
            ErrorCause::Syntax(SyntaxError::UnsupportedDoubleBracketCommand)
        );
        assert_eq!(*e.location.code.value.borrow(), " [[ foo ]]");
        assert_eq!(e.location.code.start_line_number.get(), 1);
        assert_eq!(*e.location.code.source, Source::Unknown);
        assert_eq!(e.location.range, 1..3);
    }

    #[test]
    fn parser_command_eof() {
        let mut lexer = Lexer::with_code("");
        let mut parser = Parser::new(&mut lexer);

        let result = parser.command().now_or_never().unwrap().unwrap();
        assert_eq!(result, Rec::Parsed(None));
    }
}