src/mac.rs

use super::*;

ast_struct! {
    /// Represents a macro invocation. The Path indicates which macro
    /// is being invoked, and the vector of token-trees contains the source
    /// of the macro invocation.
    ///
    /// NB: the additional ident for a `macro_rules`-style macro is actually
    /// stored in the enclosing item. Oog.
    pub struct Mac {
        pub path: Path,
        pub tts: Vec<TokenTree>,
    }
}

ast_enum! {
    /// When the main rust parser encounters a syntax-extension invocation, it
    /// parses the arguments to the invocation as a token-tree. This is a very
    /// loose structure, such that all sorts of different AST-fragments can
    /// be passed to syntax extensions using a uniform type.
    ///
    /// If the syntax extension is an MBE macro, it will attempt to match its
    /// LHS token tree against the provided token tree, and if it finds a
    /// match, will transcribe the RHS token tree, splicing in any captured
    /// `macro_parser::matched_nonterminals` into the `SubstNt`s it finds.
    ///
    /// The RHS of an MBE macro is the only place `SubstNt`s are substituted.
    /// Nothing special happens to misnamed or misplaced `SubstNt`s.
    pub enum TokenTree {
        /// A single token
        Token(Token),
        /// A delimited sequence of token trees
        Delimited(Delimited),
    }
}

ast_struct! {
    pub struct Delimited {
        /// The type of delimiter
        pub delim: DelimToken,
        /// The delimited sequence of token trees
        pub tts: Vec<TokenTree>,
    }
}

ast_enum! {
    pub enum Token {
        // Expression-operator symbols.
        Eq,
        Lt,
        Le,
        EqEq,
        Ne,
        Ge,
        Gt,
        AndAnd,
        OrOr,
        Not,
        Tilde,
        BinOp(BinOpToken),
        BinOpEq(BinOpToken),

        // Structural symbols
        At,
        Dot,
        DotDot,
        DotDotDot,
        Comma,
        Semi,
        Colon,
        ModSep,
        RArrow,
        LArrow,
        FatArrow,
        Pound,
        Dollar,
        Question,

        // Literals
        Literal(Lit),

        // Name components
        Ident(Ident),
        Underscore,
        Lifetime(Ident),

        DocComment(String),
    }
}

ast_enum! {
    #[derive(Copy)]
    pub enum BinOpToken {
        Plus,
        Minus,
        Star,
        Slash,
        Percent,
        Caret,
        And,
        Or,
        Shl,
        Shr,
    }
}

ast_enum! {
    /// A delimiter token
    #[derive(Copy)]
    pub enum DelimToken {
        /// A round parenthesis: `(` or `)`
        Paren,
        /// A square bracket: `[` or `]`
        Bracket,
        /// A curly brace: `{` or `}`
        Brace,
    }
}

#[cfg(feature = "parsing")]
pub mod parsing {
    use super::*;
    use Lifetime;
    use generics::parsing::lifetime;
    use ident::parsing::word;
    use lit::parsing::lit;
    use synom::space::{block_comment, whitespace};
    use ty::parsing::path;

    named!(pub mac -> Mac, do_parse!(
        what: path >>
        punct!("!") >>
        body: delimited >>
        (Mac {
            path: what,
            tts: vec![TokenTree::Delimited(body)],
        })
    ));

    named!(pub token_trees -> Vec<TokenTree>, many0!(token_tree));

    named!(pub delimited -> Delimited, alt!(
        delimited!(
            punct!("("),
            token_trees,
            punct!(")")
        ) => { |tts| Delimited { delim: DelimToken::Paren, tts: tts } }
        |
        delimited!(
            punct!("["),
            token_trees,
            punct!("]")
        ) => { |tts| Delimited { delim: DelimToken::Bracket, tts: tts } }
        |
        delimited!(
            punct!("{"),
            token_trees,
            punct!("}")
        ) => { |tts| Delimited { delim: DelimToken::Brace, tts: tts } }
    ));

    named!(pub token_tree -> TokenTree, alt!(
        map!(token, TokenTree::Token)
        |
        map!(delimited, TokenTree::Delimited)
    ));

    named!(token -> Token, alt!(
        keyword!("_") => { |_| Token::Underscore }
        |
        punct!("&&") => { |_| Token::AndAnd } // must be before BinOp
        |
        punct!("||") => { |_| Token::OrOr } // must be before BinOp
        |
        punct!("->") => { |_| Token::RArrow } // must be before BinOp
        |
        punct!("<-") => { |_| Token::LArrow } // must be before Lt
        |
        punct!("=>") => { |_| Token::FatArrow } // must be before Eq
        |
        punct!("...") => { |_| Token::DotDotDot } // must be before DotDot
        |
        punct!("..") => { |_| Token::DotDot } // must be before Dot
        |
        punct!(".") => { |_| Token::Dot }
        |
        map!(doc_comment, Token::DocComment) // must be before bin_op
        |
        map!(bin_op_eq, Token::BinOpEq) // must be before bin_op
        |
        map!(bin_op, Token::BinOp)
        |
        map!(lit, Token::Literal)
        |
        map!(word, Token::Ident)
        |
        map!(lifetime, |lt: Lifetime| Token::Lifetime(lt.ident))
        |
        punct!("<=") => { |_| Token::Le }
        |
        punct!("==") => { |_| Token::EqEq }
        |
        punct!("!=") => { |_| Token::Ne }
        |
        punct!(">=") => { |_| Token::Ge }
        |
        punct!("::") => { |_| Token::ModSep }
        |
        punct!("=") => { |_| Token::Eq }
        |
        punct!("<") => { |_| Token::Lt }
        |
        punct!(">") => { |_| Token::Gt }
        |
        punct!("!") => { |_| Token::Not }
        |
        punct!("~") => { |_| Token::Tilde }
        |
        punct!("@") => { |_| Token::At }
        |
        punct!(",") => { |_| Token::Comma }
        |
        punct!(";") => { |_| Token::Semi }
        |
        punct!(":") => { |_| Token::Colon }
        |
        punct!("#") => { |_| Token::Pound }
        |
        punct!("$") => { |_| Token::Dollar }
        |
        punct!("?") => { |_| Token::Question }
    ));

    named!(bin_op -> BinOpToken, alt!(
        punct!("+") => { |_| BinOpToken::Plus }
        |
        punct!("-") => { |_| BinOpToken::Minus }
        |
        punct!("*") => { |_| BinOpToken::Star }
        |
        punct!("/") => { |_| BinOpToken::Slash }
        |
        punct!("%") => { |_| BinOpToken::Percent }
        |
        punct!("^") => { |_| BinOpToken::Caret }
        |
        punct!("&") => { |_| BinOpToken::And }
        |
        punct!("|") => { |_| BinOpToken::Or }
        |
        punct!("<<") => { |_| BinOpToken::Shl }
        |
        punct!(">>") => { |_| BinOpToken::Shr }
    ));

    named!(bin_op_eq -> BinOpToken, alt!(
        punct!("+=") => { |_| BinOpToken::Plus }
        |
        punct!("-=") => { |_| BinOpToken::Minus }
        |
        punct!("*=") => { |_| BinOpToken::Star }
        |
        punct!("/=") => { |_| BinOpToken::Slash }
        |
        punct!("%=") => { |_| BinOpToken::Percent }
        |
        punct!("^=") => { |_| BinOpToken::Caret }
        |
        punct!("&=") => { |_| BinOpToken::And }
        |
        punct!("|=") => { |_| BinOpToken::Or }
        |
        punct!("<<=") => { |_| BinOpToken::Shl }
        |
        punct!(">>=") => { |_| BinOpToken::Shr }
    ));

    named!(doc_comment -> String, alt!(
        do_parse!(
            punct!("//!") >>
            content: take_until!("\n") >>
            (format!("//!{}", content))
        )
        |
        do_parse!(
            option!(whitespace) >>
            peek!(tag!("/*!")) >>
            com: block_comment >>
            (com.to_owned())
        )
        |
        do_parse!(
            punct!("///") >>
            not!(tag!("/")) >>
            content: take_until!("\n") >>
            (format!("///{}", content))
        )
        |
        do_parse!(
            option!(whitespace) >>
            peek!(tuple!(tag!("/**"), not!(tag!("*")))) >>
            com: block_comment >>
            (com.to_owned())
        )
    ));
}

#[cfg(feature = "printing")]
mod printing {
    use super::*;
    use quote::{Tokens, ToTokens};

    impl ToTokens for Mac {
        fn to_tokens(&self, tokens: &mut Tokens) {
            self.path.to_tokens(tokens);
            tokens.append("!");
            for tt in &self.tts {
                tt.to_tokens(tokens);
            }
        }
    }

    impl ToTokens for TokenTree {
        fn to_tokens(&self, tokens: &mut Tokens) {
            match *self {
                TokenTree::Token(ref token) => token.to_tokens(tokens),
                TokenTree::Delimited(ref delimited) => delimited.to_tokens(tokens),
            }
        }
    }

    impl DelimToken {
        fn open(&self) -> &'static str {
            match *self {
                DelimToken::Paren => "(",
                DelimToken::Bracket => "[",
                DelimToken::Brace => "{",
            }
        }

        fn close(&self) -> &'static str {
            match *self {
                DelimToken::Paren => ")",
                DelimToken::Bracket => "]",
                DelimToken::Brace => "}",
            }
        }
    }

    impl ToTokens for Delimited {
        fn to_tokens(&self, tokens: &mut Tokens) {
            tokens.append(self.delim.open());
            for tt in &self.tts {
                tt.to_tokens(tokens);
            }
            tokens.append(self.delim.close());
        }
    }

    impl ToTokens for Token {
        fn to_tokens(&self, tokens: &mut Tokens) {
            match *self {
                Token::Eq => tokens.append("="),
                Token::Lt => tokens.append("<"),
                Token::Le => tokens.append("<="),
                Token::EqEq => tokens.append("=="),
                Token::Ne => tokens.append("!="),
                Token::Ge => tokens.append(">="),
                Token::Gt => tokens.append(">"),
                Token::AndAnd => tokens.append("&&"),
                Token::OrOr => tokens.append("||"),
                Token::Not => tokens.append("!"),
                Token::Tilde => tokens.append("~"),
                Token::BinOp(binop) => tokens.append(binop.op()),
                Token::BinOpEq(binop) => tokens.append(binop.assign_op()),
                Token::At => tokens.append("@"),
                Token::Dot => tokens.append("."),
                Token::DotDot => tokens.append(".."),
                Token::DotDotDot => tokens.append("..."),
                Token::Comma => tokens.append(","),
                Token::Semi => tokens.append(";"),
                Token::Colon => tokens.append(":"),
                Token::ModSep => tokens.append("::"),
                Token::RArrow => tokens.append("->"),
                Token::LArrow => tokens.append("<-"),
                Token::FatArrow => tokens.append("=>"),
                Token::Pound => tokens.append("#"),
                Token::Dollar => tokens.append("$"),
                Token::Question => tokens.append("?"),
                Token::Literal(ref lit) => lit.to_tokens(tokens),
                Token::Ident(ref ident) |
                Token::Lifetime(ref ident) => ident.to_tokens(tokens),
                Token::Underscore => tokens.append("_"),
                Token::DocComment(ref com) => {
                    tokens.append(&format!("{}\n", com));
                }
            }
        }
    }

    impl BinOpToken {
        fn op(&self) -> &'static str {
            match *self {
                BinOpToken::Plus => "+",
                BinOpToken::Minus => "-",
                BinOpToken::Star => "*",
                BinOpToken::Slash => "/",
                BinOpToken::Percent => "%",
                BinOpToken::Caret => "^",
                BinOpToken::And => "&",
                BinOpToken::Or => "|",
                BinOpToken::Shl => "<<",
                BinOpToken::Shr => ">>",
            }
        }

        fn assign_op(&self) -> &'static str {
            match *self {
                BinOpToken::Plus => "+=",
                BinOpToken::Minus => "-=",
                BinOpToken::Star => "*=",
                BinOpToken::Slash => "/=",
                BinOpToken::Percent => "%=",
                BinOpToken::Caret => "^=",
                BinOpToken::And => "&=",
                BinOpToken::Or => "|=",
                BinOpToken::Shl => "<<=",
                BinOpToken::Shr => ">>=",
            }
        }
    }

    impl ToTokens for BinOpToken {
        fn to_tokens(&self, tokens: &mut Tokens) {
            tokens.append(self.op());
        }
    }
}