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-rw-r--r--third_party/rust/syn/src/mac.rs219
1 files changed, 219 insertions, 0 deletions
diff --git a/third_party/rust/syn/src/mac.rs b/third_party/rust/syn/src/mac.rs
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+use super::*;
+use crate::token::{Brace, Bracket, Paren};
+use proc_macro2::TokenStream;
+#[cfg(feature = "parsing")]
+use proc_macro2::{Delimiter, Group, Span, TokenTree};
+
+#[cfg(feature = "parsing")]
+use crate::parse::{Parse, ParseStream, Parser, Result};
+
+ast_struct! {
+ /// A macro invocation: `println!("{}", mac)`.
+ ///
+ /// *This type is available only if Syn is built with the `"derive"` or `"full"`
+ /// feature.*
+ #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))]
+ pub struct Macro {
+ pub path: Path,
+ pub bang_token: Token![!],
+ pub delimiter: MacroDelimiter,
+ pub tokens: TokenStream,
+ }
+}
+
+ast_enum! {
+ /// A grouping token that surrounds a macro body: `m!(...)` or `m!{...}` or `m![...]`.
+ ///
+ /// *This type is available only if Syn is built with the `"derive"` or `"full"`
+ /// feature.*
+ #[cfg_attr(doc_cfg, doc(cfg(any(feature = "full", feature = "derive"))))]
+ pub enum MacroDelimiter {
+ Paren(Paren),
+ Brace(Brace),
+ Bracket(Bracket),
+ }
+}
+
+#[cfg(feature = "parsing")]
+fn delimiter_span_close(macro_delimiter: &MacroDelimiter) -> Span {
+ let delimiter = match macro_delimiter {
+ MacroDelimiter::Paren(_) => Delimiter::Parenthesis,
+ MacroDelimiter::Brace(_) => Delimiter::Brace,
+ MacroDelimiter::Bracket(_) => Delimiter::Bracket,
+ };
+ let mut group = Group::new(delimiter, TokenStream::new());
+ group.set_span(match macro_delimiter {
+ MacroDelimiter::Paren(token) => token.span,
+ MacroDelimiter::Brace(token) => token.span,
+ MacroDelimiter::Bracket(token) => token.span,
+ });
+ group.span_close()
+}
+
+impl Macro {
+ /// Parse the tokens within the macro invocation's delimiters into a syntax
+ /// tree.
+ ///
+ /// This is equivalent to `syn::parse2::<T>(mac.tokens)` except that it
+ /// produces a more useful span when `tokens` is empty.
+ ///
+ /// # Example
+ ///
+ /// ```
+ /// use syn::{parse_quote, Expr, ExprLit, Ident, Lit, LitStr, Macro, Token};
+ /// use syn::ext::IdentExt;
+ /// use syn::parse::{Error, Parse, ParseStream, Result};
+ /// use syn::punctuated::Punctuated;
+ ///
+ /// // The arguments expected by libcore's format_args macro, and as a
+ /// // result most other formatting and printing macros like println.
+ /// //
+ /// // println!("{} is {number:.prec$}", "x", prec=5, number=0.01)
+ /// struct FormatArgs {
+ /// format_string: Expr,
+ /// positional_args: Vec<Expr>,
+ /// named_args: Vec<(Ident, Expr)>,
+ /// }
+ ///
+ /// impl Parse for FormatArgs {
+ /// fn parse(input: ParseStream) -> Result<Self> {
+ /// let format_string: Expr;
+ /// let mut positional_args = Vec::new();
+ /// let mut named_args = Vec::new();
+ ///
+ /// format_string = input.parse()?;
+ /// while !input.is_empty() {
+ /// input.parse::<Token![,]>()?;
+ /// if input.is_empty() {
+ /// break;
+ /// }
+ /// if input.peek(Ident::peek_any) && input.peek2(Token![=]) {
+ /// while !input.is_empty() {
+ /// let name: Ident = input.call(Ident::parse_any)?;
+ /// input.parse::<Token![=]>()?;
+ /// let value: Expr = input.parse()?;
+ /// named_args.push((name, value));
+ /// if input.is_empty() {
+ /// break;
+ /// }
+ /// input.parse::<Token![,]>()?;
+ /// }
+ /// break;
+ /// }
+ /// positional_args.push(input.parse()?);
+ /// }
+ ///
+ /// Ok(FormatArgs {
+ /// format_string,
+ /// positional_args,
+ /// named_args,
+ /// })
+ /// }
+ /// }
+ ///
+ /// // Extract the first argument, the format string literal, from an
+ /// // invocation of a formatting or printing macro.
+ /// fn get_format_string(m: &Macro) -> Result<LitStr> {
+ /// let args: FormatArgs = m.parse_body()?;
+ /// match args.format_string {
+ /// Expr::Lit(ExprLit { lit: Lit::Str(lit), .. }) => Ok(lit),
+ /// other => {
+ /// // First argument was not a string literal expression.
+ /// // Maybe something like: println!(concat!(...), ...)
+ /// Err(Error::new_spanned(other, "format string must be a string literal"))
+ /// }
+ /// }
+ /// }
+ ///
+ /// fn main() {
+ /// let invocation = parse_quote! {
+ /// println!("{:?}", Instant::now())
+ /// };
+ /// let lit = get_format_string(&invocation).unwrap();
+ /// assert_eq!(lit.value(), "{:?}");
+ /// }
+ /// ```
+ #[cfg(feature = "parsing")]
+ #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))]
+ pub fn parse_body<T: Parse>(&self) -> Result<T> {
+ self.parse_body_with(T::parse)
+ }
+
+ /// Parse the tokens within the macro invocation's delimiters using the
+ /// given parser.
+ #[cfg(feature = "parsing")]
+ #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))]
+ pub fn parse_body_with<F: Parser>(&self, parser: F) -> Result<F::Output> {
+ let scope = delimiter_span_close(&self.delimiter);
+ crate::parse::parse_scoped(parser, scope, self.tokens.clone())
+ }
+}
+
+#[cfg(feature = "parsing")]
+pub fn parse_delimiter(input: ParseStream) -> Result<(MacroDelimiter, TokenStream)> {
+ input.step(|cursor| {
+ if let Some((TokenTree::Group(g), rest)) = cursor.token_tree() {
+ let span = g.span();
+ let delimiter = match g.delimiter() {
+ Delimiter::Parenthesis => MacroDelimiter::Paren(Paren(span)),
+ Delimiter::Brace => MacroDelimiter::Brace(Brace(span)),
+ Delimiter::Bracket => MacroDelimiter::Bracket(Bracket(span)),
+ Delimiter::None => {
+ return Err(cursor.error("expected delimiter"));
+ }
+ };
+ Ok(((delimiter, g.stream()), rest))
+ } else {
+ Err(cursor.error("expected delimiter"))
+ }
+ })
+}
+
+#[cfg(feature = "parsing")]
+pub mod parsing {
+ use super::*;
+ use crate::parse::{Parse, ParseStream, Result};
+
+ #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))]
+ impl Parse for Macro {
+ fn parse(input: ParseStream) -> Result<Self> {
+ let tokens;
+ Ok(Macro {
+ path: input.call(Path::parse_mod_style)?,
+ bang_token: input.parse()?,
+ delimiter: {
+ let (delimiter, content) = parse_delimiter(input)?;
+ tokens = content;
+ delimiter
+ },
+ tokens,
+ })
+ }
+ }
+}
+
+#[cfg(feature = "printing")]
+mod printing {
+ use super::*;
+ use proc_macro2::TokenStream;
+ use quote::ToTokens;
+
+ #[cfg_attr(doc_cfg, doc(cfg(feature = "printing")))]
+ impl ToTokens for Macro {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ self.path.to_tokens(tokens);
+ self.bang_token.to_tokens(tokens);
+ match &self.delimiter {
+ MacroDelimiter::Paren(paren) => {
+ paren.surround(tokens, |tokens| self.tokens.to_tokens(tokens));
+ }
+ MacroDelimiter::Brace(brace) => {
+ brace.surround(tokens, |tokens| self.tokens.to_tokens(tokens));
+ }
+ MacroDelimiter::Bracket(bracket) => {
+ bracket.surround(tokens, |tokens| self.tokens.to_tokens(tokens));
+ }
+ }
+ }
+ }
+}