diff options
Diffstat (limited to 'src/mac.rs')
| -rw-r--r-- | src/mac.rs | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/src/mac.rs b/src/mac.rs new file mode 100644 index 0000000..9c4c119 --- /dev/null +++ b/src/mac.rs @@ -0,0 +1,220 @@ +use crate::algorithm::Printer; +use crate::token::Token; +use crate::INDENT; +use proc_macro2::{Delimiter, Spacing, TokenStream}; +use syn::{Ident, Macro, MacroDelimiter, PathArguments}; + +impl Printer { + pub fn mac(&mut self, mac: &Macro, ident: Option<&Ident>) { + let is_macro_rules = mac.path.leading_colon.is_none() + && mac.path.segments.len() == 1 + && matches!(mac.path.segments[0].arguments, PathArguments::None) + && mac.path.segments[0].ident == "macro_rules"; + if is_macro_rules { + if let Some(ident) = ident { + self.macro_rules(ident, &mac.tokens); + return; + } + } + self.path(&mac.path); + self.word("!"); + if let Some(ident) = ident { + self.nbsp(); + self.ident(ident); + } + let (open, close, delimiter_break) = match mac.delimiter { + MacroDelimiter::Paren(_) => ("(", ")", Self::zerobreak as fn(&mut Self)), + MacroDelimiter::Brace(_) => (" {", "}", Self::hardbreak as fn(&mut Self)), + MacroDelimiter::Bracket(_) => ("[", "]", Self::zerobreak as fn(&mut Self)), + }; + self.word(open); + self.cbox(INDENT); + delimiter_break(self); + self.ibox(0); + self.macro_rules_tokens(mac.tokens.clone(), false); + self.end(); + delimiter_break(self); + self.offset(-INDENT); + self.end(); + self.word(close); + } + + pub fn mac_semi_if_needed(&mut self, delimiter: &MacroDelimiter) { + match delimiter { + MacroDelimiter::Paren(_) | MacroDelimiter::Bracket(_) => self.word(";"), + MacroDelimiter::Brace(_) => {} + } + } + + fn macro_rules(&mut self, name: &Ident, rules: &TokenStream) { + enum State { + Start, + Matcher, + Equal, + Greater, + Expander, + } + + use State::*; + + self.word("macro_rules! "); + self.ident(name); + self.word(" {"); + self.cbox(INDENT); + self.hardbreak_if_nonempty(); + let mut state = State::Start; + for tt in rules.clone() { + let token = Token::from(tt); + match (state, token) { + (Start, Token::Group(delimiter, stream)) => { + self.delimiter_open(delimiter); + if !stream.is_empty() { + self.cbox(INDENT); + self.zerobreak(); + self.ibox(0); + self.macro_rules_tokens(stream, true); + self.end(); + self.zerobreak(); + self.offset(-INDENT); + self.end(); + } + self.delimiter_close(delimiter); + state = Matcher; + } + (Matcher, Token::Punct('=', Spacing::Joint)) => { + self.word(" ="); + state = Equal; + } + (Equal, Token::Punct('>', Spacing::Alone)) => { + self.word(">"); + state = Greater; + } + (Greater, Token::Group(_delimiter, stream)) => { + self.word(" {"); + self.neverbreak(); + if !stream.is_empty() { + self.cbox(INDENT); + self.hardbreak(); + self.ibox(0); + self.macro_rules_tokens(stream, false); + self.end(); + self.hardbreak(); + self.offset(-INDENT); + self.end(); + } + self.word("}"); + state = Expander; + } + (Expander, Token::Punct(';', Spacing::Alone)) => { + self.word(";"); + self.hardbreak(); + state = Start; + } + _ => unimplemented!("bad macro_rules syntax"), + } + } + match state { + Start => {} + Expander => { + self.word(";"); + self.hardbreak(); + } + _ => self.hardbreak(), + } + self.offset(-INDENT); + self.end(); + self.word("}"); + } + + fn macro_rules_tokens(&mut self, stream: TokenStream, matcher: bool) { + #[derive(PartialEq)] + enum State { + Start, + Dollar, + DollarIdent, + DollarIdentColon, + DollarParen, + DollarParenSep, + Pound, + PoundBang, + Dot, + Colon, + Colon2, + Ident, + IdentBang, + Delim, + Other, + } + + use State::*; + + let mut state = Start; + let mut previous_is_joint = true; + for tt in stream { + let token = Token::from(tt); + let (needs_space, next_state) = match (&state, &token) { + (Dollar, Token::Ident(_)) => (false, if matcher { DollarIdent } else { Other }), + (DollarIdent, Token::Punct(':', Spacing::Alone)) => (false, DollarIdentColon), + (DollarIdentColon, Token::Ident(_)) => (false, Other), + (DollarParen, Token::Punct('+' | '*' | '?', Spacing::Alone)) => (false, Other), + (DollarParen, Token::Ident(_) | Token::Literal(_)) => (false, DollarParenSep), + (DollarParen, Token::Punct(_, Spacing::Joint)) => (false, DollarParen), + (DollarParen, Token::Punct(_, Spacing::Alone)) => (false, DollarParenSep), + (DollarParenSep, Token::Punct('+' | '*', _)) => (false, Other), + (Pound, Token::Punct('!', _)) => (false, PoundBang), + (Dollar, Token::Group(Delimiter::Parenthesis, _)) => (false, DollarParen), + (Pound | PoundBang, Token::Group(Delimiter::Bracket, _)) => (false, Other), + (Ident, Token::Group(Delimiter::Parenthesis | Delimiter::Bracket, _)) => { + (false, Delim) + } + (Ident, Token::Punct('!', Spacing::Alone)) => (false, IdentBang), + (IdentBang, Token::Group(Delimiter::Parenthesis | Delimiter::Bracket, _)) => { + (false, Other) + } + (Colon, Token::Punct(':', _)) => (false, Colon2), + (_, Token::Group(Delimiter::Parenthesis | Delimiter::Bracket, _)) => (true, Delim), + (_, Token::Group(Delimiter::Brace | Delimiter::None, _)) => (true, Other), + (_, Token::Ident(ident)) if !is_keyword(ident) => { + (state != Dot && state != Colon2, Ident) + } + (_, Token::Literal(_)) => (state != Dot, Ident), + (_, Token::Punct(',' | ';', _)) => (false, Other), + (_, Token::Punct('.', _)) if !matcher => (state != Ident && state != Delim, Dot), + (_, Token::Punct(':', Spacing::Joint)) => (state != Ident, Colon), + (_, Token::Punct('$', _)) => (true, Dollar), + (_, Token::Punct('#', _)) => (true, Pound), + (_, _) => (true, Other), + }; + if !previous_is_joint { + if needs_space { + self.space(); + } else if let Token::Punct('.', _) = token { + self.zerobreak(); + } + } + previous_is_joint = match token { + Token::Punct(_, Spacing::Joint) | Token::Punct('$', _) => true, + _ => false, + }; + self.single_token( + token, + if matcher { + |printer, stream| printer.macro_rules_tokens(stream, true) + } else { + |printer, stream| printer.macro_rules_tokens(stream, false) + }, + ); + state = next_state; + } + } +} + +fn is_keyword(ident: &Ident) -> bool { + match ident.to_string().as_str() { + "as" | "box" | "break" | "const" | "continue" | "crate" | "else" | "enum" | "extern" + | "fn" | "for" | "if" | "impl" | "in" | "let" | "loop" | "macro" | "match" | "mod" + | "move" | "mut" | "pub" | "ref" | "return" | "static" | "struct" | "trait" | "type" + | "unsafe" | "use" | "where" | "while" | "yield" => true, + _ => false, + } +} |