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-rw-r--r--quote/src/ext.rs112
-rw-r--r--quote/src/format.rs164
-rw-r--r--quote/src/ident_fragment.rs72
-rw-r--r--quote/src/lib.rs948
-rw-r--r--quote/src/runtime.rs373
-rw-r--r--quote/src/spanned.rs42
-rw-r--r--quote/src/to_tokens.rs209
7 files changed, 1920 insertions, 0 deletions
diff --git a/quote/src/ext.rs b/quote/src/ext.rs
new file mode 100644
index 0000000..9e9b4a5
--- /dev/null
+++ b/quote/src/ext.rs
@@ -0,0 +1,112 @@
+use super::ToTokens;
+
+use std::iter;
+
+use proc_macro2::{TokenStream, TokenTree};
+
+/// TokenStream extension trait with methods for appending tokens.
+///
+/// This trait is sealed and cannot be implemented outside of the `quote` crate.
+pub trait TokenStreamExt: private::Sealed {
+ /// For use by `ToTokens` implementations.
+ ///
+ /// Appends the token specified to this list of tokens.
+ fn append<U>(&mut self, token: U)
+ where
+ U: Into<TokenTree>;
+
+ /// For use by `ToTokens` implementations.
+ ///
+ /// ```
+ /// # use quote::{quote, TokenStreamExt, ToTokens};
+ /// # use proc_macro2::TokenStream;
+ /// #
+ /// struct X;
+ ///
+ /// impl ToTokens for X {
+ /// fn to_tokens(&self, tokens: &mut TokenStream) {
+ /// tokens.append_all(&[true, false]);
+ /// }
+ /// }
+ ///
+ /// let tokens = quote!(#X);
+ /// assert_eq!(tokens.to_string(), "true false");
+ /// ```
+ fn append_all<I>(&mut self, iter: I)
+ where
+ I: IntoIterator,
+ I::Item: ToTokens;
+
+ /// For use by `ToTokens` implementations.
+ ///
+ /// Appends all of the items in the iterator `I`, separated by the tokens
+ /// `U`.
+ fn append_separated<I, U>(&mut self, iter: I, op: U)
+ where
+ I: IntoIterator,
+ I::Item: ToTokens,
+ U: ToTokens;
+
+ /// For use by `ToTokens` implementations.
+ ///
+ /// Appends all tokens in the iterator `I`, appending `U` after each
+ /// element, including after the last element of the iterator.
+ fn append_terminated<I, U>(&mut self, iter: I, term: U)
+ where
+ I: IntoIterator,
+ I::Item: ToTokens,
+ U: ToTokens;
+}
+
+impl TokenStreamExt for TokenStream {
+ fn append<U>(&mut self, token: U)
+ where
+ U: Into<TokenTree>,
+ {
+ self.extend(iter::once(token.into()));
+ }
+
+ fn append_all<I>(&mut self, iter: I)
+ where
+ I: IntoIterator,
+ I::Item: ToTokens,
+ {
+ for token in iter {
+ token.to_tokens(self);
+ }
+ }
+
+ fn append_separated<I, U>(&mut self, iter: I, op: U)
+ where
+ I: IntoIterator,
+ I::Item: ToTokens,
+ U: ToTokens,
+ {
+ for (i, token) in iter.into_iter().enumerate() {
+ if i > 0 {
+ op.to_tokens(self);
+ }
+ token.to_tokens(self);
+ }
+ }
+
+ fn append_terminated<I, U>(&mut self, iter: I, term: U)
+ where
+ I: IntoIterator,
+ I::Item: ToTokens,
+ U: ToTokens,
+ {
+ for token in iter {
+ token.to_tokens(self);
+ term.to_tokens(self);
+ }
+ }
+}
+
+mod private {
+ use proc_macro2::TokenStream;
+
+ pub trait Sealed {}
+
+ impl Sealed for TokenStream {}
+}
diff --git a/quote/src/format.rs b/quote/src/format.rs
new file mode 100644
index 0000000..13c8811
--- /dev/null
+++ b/quote/src/format.rs
@@ -0,0 +1,164 @@
+/// Formatting macro for constructing `Ident`s.
+///
+/// <br>
+///
+/// # Syntax
+///
+/// Syntax is copied from the [`format!`] macro, supporting both positional and
+/// named arguments.
+///
+/// Only a limited set of formatting traits are supported. The current mapping
+/// of format types to traits is:
+///
+/// * `{}` ⇒ [`IdentFragment`]
+/// * `{:o}` ⇒ [`Octal`](`std::fmt::Octal`)
+/// * `{:x}` ⇒ [`LowerHex`](`std::fmt::LowerHex`)
+/// * `{:X}` ⇒ [`UpperHex`](`std::fmt::UpperHex`)
+/// * `{:b}` ⇒ [`Binary`](`std::fmt::Binary`)
+///
+/// See [`std::fmt`] for more information.
+///
+/// <br>
+///
+/// # IdentFragment
+///
+/// Unlike `format!`, this macro uses the [`IdentFragment`] formatting trait by
+/// default. This trait is like `Display`, with a few differences:
+///
+/// * `IdentFragment` is only implemented for a limited set of types, such as
+/// unsigned integers and strings.
+/// * [`Ident`] arguments will have their `r#` prefixes stripped, if present.
+///
+/// [`Ident`]: `proc_macro2::Ident`
+///
+/// <br>
+///
+/// # Hygiene
+///
+/// The [`Span`] of the first `Ident` argument is used as the span of the final
+/// identifier, falling back to [`Span::call_site`] when no identifiers are
+/// provided.
+///
+/// ```
+/// # use quote::format_ident;
+/// # let ident = format_ident!("Ident");
+/// // If `ident` is an Ident, the span of `my_ident` will be inherited from it.
+/// let my_ident = format_ident!("My{}{}", ident, "IsCool");
+/// assert_eq!(my_ident, "MyIdentIsCool");
+/// ```
+///
+/// Alternatively, the span can be overridden by passing the `span` named
+/// argument.
+///
+/// ```
+/// # use quote::format_ident;
+/// # const IGNORE_TOKENS: &'static str = stringify! {
+/// let my_span = /* ... */;
+/// # };
+/// # let my_span = proc_macro2::Span::call_site();
+/// format_ident!("MyIdent", span = my_span);
+/// ```
+///
+/// [`Span`]: `proc_macro2::Span`
+/// [`Span::call_site`]: `proc_macro2::Span::call_site`
+///
+/// <p><br></p>
+///
+/// # Panics
+///
+/// This method will panic if the resulting formatted string is not a valid
+/// identifier.
+///
+/// <br>
+///
+/// # Examples
+///
+/// Composing raw and non-raw identifiers:
+/// ```
+/// # use quote::format_ident;
+/// let my_ident = format_ident!("My{}", "Ident");
+/// assert_eq!(my_ident, "MyIdent");
+///
+/// let raw = format_ident!("r#Raw");
+/// assert_eq!(raw, "r#Raw");
+///
+/// let my_ident_raw = format_ident!("{}Is{}", my_ident, raw);
+/// assert_eq!(my_ident_raw, "MyIdentIsRaw");
+/// ```
+///
+/// Integer formatting options:
+/// ```
+/// # use quote::format_ident;
+/// let num: u32 = 10;
+///
+/// let decimal = format_ident!("Id_{}", num);
+/// assert_eq!(decimal, "Id_10");
+///
+/// let octal = format_ident!("Id_{:o}", num);
+/// assert_eq!(octal, "Id_12");
+///
+/// let binary = format_ident!("Id_{:b}", num);
+/// assert_eq!(binary, "Id_1010");
+///
+/// let lower_hex = format_ident!("Id_{:x}", num);
+/// assert_eq!(lower_hex, "Id_a");
+///
+/// let upper_hex = format_ident!("Id_{:X}", num);
+/// assert_eq!(upper_hex, "Id_A");
+/// ```
+#[macro_export]
+macro_rules! format_ident {
+ ($fmt:expr) => {
+ $crate::format_ident_impl!([
+ ::std::option::Option::None,
+ $fmt
+ ])
+ };
+
+ ($fmt:expr, $($rest:tt)*) => {
+ $crate::format_ident_impl!([
+ ::std::option::Option::None,
+ $fmt
+ ] $($rest)*)
+ };
+}
+
+#[macro_export]
+#[doc(hidden)]
+macro_rules! format_ident_impl {
+ // Final state
+ ([$span:expr, $($fmt:tt)*]) => {
+ $crate::__rt::mk_ident(&format!($($fmt)*), $span)
+ };
+
+ // Span argument
+ ([$old:expr, $($fmt:tt)*] span = $span:expr) => {
+ $crate::format_ident_impl!([$old, $($fmt)*] span = $span,)
+ };
+ ([$old:expr, $($fmt:tt)*] span = $span:expr, $($rest:tt)*) => {
+ $crate::format_ident_impl!([
+ ::std::option::Option::Some::<$crate::__rt::Span>($span),
+ $($fmt)*
+ ] $($rest)*)
+ };
+
+ // Named argument
+ ([$span:expr, $($fmt:tt)*] $name:ident = $arg:expr) => {
+ $crate::format_ident_impl!([$span, $($fmt)*] $name = $arg,)
+ };
+ ([$span:expr, $($fmt:tt)*] $name:ident = $arg:expr, $($rest:tt)*) => {
+ match $crate::__rt::IdentFragmentAdapter(&$arg) {
+ arg => $crate::format_ident_impl!([$span.or(arg.span()), $($fmt)*, $name = arg] $($rest)*),
+ }
+ };
+
+ // Positional argument
+ ([$span:expr, $($fmt:tt)*] $arg:expr) => {
+ $crate::format_ident_impl!([$span, $($fmt)*] $arg,)
+ };
+ ([$span:expr, $($fmt:tt)*] $arg:expr, $($rest:tt)*) => {
+ match $crate::__rt::IdentFragmentAdapter(&$arg) {
+ arg => $crate::format_ident_impl!([$span.or(arg.span()), $($fmt)*, arg] $($rest)*),
+ }
+ };
+}
diff --git a/quote/src/ident_fragment.rs b/quote/src/ident_fragment.rs
new file mode 100644
index 0000000..09ead65
--- /dev/null
+++ b/quote/src/ident_fragment.rs
@@ -0,0 +1,72 @@
+use proc_macro2::{Ident, Span};
+use std::fmt;
+
+/// Specialized formatting trait used by `format_ident!`.
+///
+/// [`Ident`] arguments formatted using this trait will have their `r#` prefix
+/// stripped, if present.
+///
+/// See [`format_ident!`] for more information.
+pub trait IdentFragment {
+ /// Format this value as an identifier fragment.
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result;
+
+ /// Span associated with this `IdentFragment`.
+ ///
+ /// If non-`None`, may be inherited by formatted identifiers.
+ fn span(&self) -> Option<Span> {
+ None
+ }
+}
+
+impl<'a, T: IdentFragment + ?Sized> IdentFragment for &'a T {
+ fn span(&self) -> Option<Span> {
+ <T as IdentFragment>::span(*self)
+ }
+
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ IdentFragment::fmt(*self, f)
+ }
+}
+
+impl<'a, T: IdentFragment + ?Sized> IdentFragment for &'a mut T {
+ fn span(&self) -> Option<Span> {
+ <T as IdentFragment>::span(*self)
+ }
+
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ IdentFragment::fmt(*self, f)
+ }
+}
+
+impl IdentFragment for Ident {
+ fn span(&self) -> Option<Span> {
+ Some(self.span())
+ }
+
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ let id = self.to_string();
+ if id.starts_with("r#") {
+ fmt::Display::fmt(&id[2..], f)
+ } else {
+ fmt::Display::fmt(&id[..], f)
+ }
+ }
+}
+
+// Limited set of types which this is implemented for, as we want to avoid types
+// which will often include non-identifier characters in their `Display` impl.
+macro_rules! ident_fragment_display {
+ ($($T:ty),*) => {
+ $(
+ impl IdentFragment for $T {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ fmt::Display::fmt(self, f)
+ }
+ }
+ )*
+ }
+}
+
+ident_fragment_display!(bool, str, String);
+ident_fragment_display!(u8, u16, u32, u64, u128, usize);
diff --git a/quote/src/lib.rs b/quote/src/lib.rs
new file mode 100644
index 0000000..3341a16
--- /dev/null
+++ b/quote/src/lib.rs
@@ -0,0 +1,948 @@
+//! This crate provides the [`quote!`] macro for turning Rust syntax tree data
+//! structures into tokens of source code.
+//!
+//! [`quote!`]: macro.quote.html
+//!
+//! Procedural macros in Rust receive a stream of tokens as input, execute
+//! arbitrary Rust code to determine how to manipulate those tokens, and produce
+//! a stream of tokens to hand back to the compiler to compile into the caller's
+//! crate. Quasi-quoting is a solution to one piece of that &mdash; producing
+//! tokens to return to the compiler.
+//!
+//! The idea of quasi-quoting is that we write *code* that we treat as *data*.
+//! Within the `quote!` macro, we can write what looks like code to our text
+//! editor or IDE. We get all the benefits of the editor's brace matching,
+//! syntax highlighting, indentation, and maybe autocompletion. But rather than
+//! compiling that as code into the current crate, we can treat it as data, pass
+//! it around, mutate it, and eventually hand it back to the compiler as tokens
+//! to compile into the macro caller's crate.
+//!
+//! This crate is motivated by the procedural macro use case, but is a
+//! general-purpose Rust quasi-quoting library and is not specific to procedural
+//! macros.
+//!
+//! ```toml
+//! [dependencies]
+//! quote = "1.0"
+//! ```
+//!
+//! <br>
+//!
+//! # Example
+//!
+//! The following quasi-quoted block of code is something you might find in [a]
+//! procedural macro having to do with data structure serialization. The `#var`
+//! syntax performs interpolation of runtime variables into the quoted tokens.
+//! Check out the documentation of the [`quote!`] macro for more detail about
+//! the syntax. See also the [`quote_spanned!`] macro which is important for
+//! implementing hygienic procedural macros.
+//!
+//! [a]: https://serde.rs/
+//! [`quote_spanned!`]: macro.quote_spanned.html
+//!
+//! ```
+//! # use quote::quote;
+//! #
+//! # let generics = "";
+//! # let where_clause = "";
+//! # let field_ty = "";
+//! # let item_ty = "";
+//! # let path = "";
+//! # let value = "";
+//! #
+//! let tokens = quote! {
+//! struct SerializeWith #generics #where_clause {
+//! value: &'a #field_ty,
+//! phantom: core::marker::PhantomData<#item_ty>,
+//! }
+//!
+//! impl #generics serde::Serialize for SerializeWith #generics #where_clause {
+//! fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+//! where
+//! S: serde::Serializer,
+//! {
+//! #path(self.value, serializer)
+//! }
+//! }
+//!
+//! SerializeWith {
+//! value: #value,
+//! phantom: core::marker::PhantomData::<#item_ty>,
+//! }
+//! };
+//! ```
+
+// Quote types in rustdoc of other crates get linked to here.
+#![doc(html_root_url = "https://docs.rs/quote/1.0.2")]
+
+#[cfg(all(
+ not(all(target_arch = "wasm32", target_os = "unknown")),
+ feature = "proc-macro"
+))]
+extern crate proc_macro;
+
+mod ext;
+mod format;
+mod ident_fragment;
+mod to_tokens;
+
+// Not public API.
+#[doc(hidden)]
+#[path = "runtime.rs"]
+pub mod __rt;
+
+pub use crate::ext::TokenStreamExt;
+pub use crate::ident_fragment::IdentFragment;
+pub use crate::to_tokens::ToTokens;
+
+// Not public API.
+#[doc(hidden)]
+pub mod spanned;
+
+/// The whole point.
+///
+/// Performs variable interpolation against the input and produces it as
+/// [`proc_macro2::TokenStream`].
+///
+/// Note: for returning tokens to the compiler in a procedural macro, use
+/// `.into()` on the result to convert to [`proc_macro::TokenStream`].
+///
+/// [`TokenStream`]: https://docs.rs/proc-macro2/1.0/proc_macro2/struct.TokenStream.html
+///
+/// <br>
+///
+/// # Interpolation
+///
+/// Variable interpolation is done with `#var` (similar to `$var` in
+/// `macro_rules!` macros). This grabs the `var` variable that is currently in
+/// scope and inserts it in that location in the output tokens. Any type
+/// implementing the [`ToTokens`] trait can be interpolated. This includes most
+/// Rust primitive types as well as most of the syntax tree types from the [Syn]
+/// crate.
+///
+/// [`ToTokens`]: trait.ToTokens.html
+/// [Syn]: https://github.com/dtolnay/syn
+///
+/// Repetition is done using `#(...)*` or `#(...),*` again similar to
+/// `macro_rules!`. This iterates through the elements of any variable
+/// interpolated within the repetition and inserts a copy of the repetition body
+/// for each one. The variables in an interpolation may be a `Vec`, slice,
+/// `BTreeSet`, or any `Iterator`.
+///
+/// - `#(#var)*` — no separators
+/// - `#(#var),*` — the character before the asterisk is used as a separator
+/// - `#( struct #var; )*` — the repetition can contain other tokens
+/// - `#( #k => println!("{}", #v), )*` — even multiple interpolations
+///
+/// <br>
+///
+/// # Hygiene
+///
+/// Any interpolated tokens preserve the `Span` information provided by their
+/// `ToTokens` implementation. Tokens that originate within the `quote!`
+/// invocation are spanned with [`Span::call_site()`].
+///
+/// [`Span::call_site()`]: https://docs.rs/proc-macro2/1.0/proc_macro2/struct.Span.html#method.call_site
+///
+/// A different span can be provided through the [`quote_spanned!`] macro.
+///
+/// [`quote_spanned!`]: macro.quote_spanned.html
+///
+/// <br>
+///
+/// # Return type
+///
+/// The macro evaluates to an expression of type `proc_macro2::TokenStream`.
+/// Meanwhile Rust procedural macros are expected to return the type
+/// `proc_macro::TokenStream`.
+///
+/// The difference between the two types is that `proc_macro` types are entirely
+/// specific to procedural macros and cannot ever exist in code outside of a
+/// procedural macro, while `proc_macro2` types may exist anywhere including
+/// tests and non-macro code like main.rs and build.rs. This is why even the
+/// procedural macro ecosystem is largely built around `proc_macro2`, because
+/// that ensures the libraries are unit testable and accessible in non-macro
+/// contexts.
+///
+/// There is a [`From`]-conversion in both directions so returning the output of
+/// `quote!` from a procedural macro usually looks like `tokens.into()` or
+/// `proc_macro::TokenStream::from(tokens)`.
+///
+/// [`From`]: https://doc.rust-lang.org/std/convert/trait.From.html
+///
+/// <br>
+///
+/// # Examples
+///
+/// ### Procedural macro
+///
+/// The structure of a basic procedural macro is as follows. Refer to the [Syn]
+/// crate for further useful guidance on using `quote!` as part of a procedural
+/// macro.
+///
+/// [Syn]: https://github.com/dtolnay/syn
+///
+/// ```
+/// # #[cfg(any())]
+/// extern crate proc_macro;
+/// # extern crate proc_macro2;
+///
+/// # #[cfg(any())]
+/// use proc_macro::TokenStream;
+/// # use proc_macro2::TokenStream;
+/// use quote::quote;
+///
+/// # const IGNORE_TOKENS: &'static str = stringify! {
+/// #[proc_macro_derive(HeapSize)]
+/// # };
+/// pub fn derive_heap_size(input: TokenStream) -> TokenStream {
+/// // Parse the input and figure out what implementation to generate...
+/// # const IGNORE_TOKENS: &'static str = stringify! {
+/// let name = /* ... */;
+/// let expr = /* ... */;
+/// # };
+/// #
+/// # let name = 0;
+/// # let expr = 0;
+///
+/// let expanded = quote! {
+/// // The generated impl.
+/// impl heapsize::HeapSize for #name {
+/// fn heap_size_of_children(&self) -> usize {
+/// #expr
+/// }
+/// }
+/// };
+///
+/// // Hand the output tokens back to the compiler.
+/// TokenStream::from(expanded)
+/// }
+/// ```
+///
+/// <p><br></p>
+///
+/// ### Combining quoted fragments
+///
+/// Usually you don't end up constructing an entire final `TokenStream` in one
+/// piece. Different parts may come from different helper functions. The tokens
+/// produced by `quote!` themselves implement `ToTokens` and so can be
+/// interpolated into later `quote!` invocations to build up a final result.
+///
+/// ```
+/// # use quote::quote;
+/// #
+/// let type_definition = quote! {...};
+/// let methods = quote! {...};
+///
+/// let tokens = quote! {
+/// #type_definition
+/// #methods
+/// };
+/// ```
+///
+/// <p><br></p>
+///
+/// ### Constructing identifiers
+///
+/// Suppose we have an identifier `ident` which came from somewhere in a macro
+/// input and we need to modify it in some way for the macro output. Let's
+/// consider prepending the identifier with an underscore.
+///
+/// Simply interpolating the identifier next to an underscore will not have the
+/// behavior of concatenating them. The underscore and the identifier will
+/// continue to be two separate tokens as if you had written `_ x`.
+///
+/// ```
+/// # use proc_macro2::{self as syn, Span};
+/// # use quote::quote;
+/// #
+/// # let ident = syn::Ident::new("i", Span::call_site());
+/// #
+/// // incorrect
+/// quote! {
+/// let mut _#ident = 0;
+/// }
+/// # ;
+/// ```
+///
+/// The solution is to build a new identifier token with the correct value. As
+/// this is such a common case, the [`format_ident!`] macro provides a
+/// convenient utility for doing so correctly.
+///
+/// ```
+/// # use proc_macro2::{Ident, Span};
+/// # use quote::{format_ident, quote};
+/// #
+/// # let ident = Ident::new("i", Span::call_site());
+/// #
+/// let varname = format_ident!("_{}", ident);
+/// quote! {
+/// let mut #varname = 0;
+/// }
+/// # ;
+/// ```
+///
+/// Alternatively, the APIs provided by Syn and proc-macro2 can be used to
+/// directly build the identifier. This is roughly equivalent to the above, but
+/// will not handle `ident` being a raw identifier.
+///
+/// ```
+/// # use proc_macro2::{self as syn, Span};
+/// # use quote::quote;
+/// #
+/// # let ident = syn::Ident::new("i", Span::call_site());
+/// #
+/// let concatenated = format!("_{}", ident);
+/// let varname = syn::Ident::new(&concatenated, ident.span());
+/// quote! {
+/// let mut #varname = 0;
+/// }
+/// # ;
+/// ```
+///
+/// <p><br></p>
+///
+/// ### Making method calls
+///
+/// Let's say our macro requires some type specified in the macro input to have
+/// a constructor called `new`. We have the type in a variable called
+/// `field_type` of type `syn::Type` and want to invoke the constructor.
+///
+/// ```
+/// # use quote::quote;
+/// #
+/// # let field_type = quote!(...);
+/// #
+/// // incorrect
+/// quote! {
+/// let value = #field_type::new();
+/// }
+/// # ;
+/// ```
+///
+/// This works only sometimes. If `field_type` is `String`, the expanded code
+/// contains `String::new()` which is fine. But if `field_type` is something
+/// like `Vec<i32>` then the expanded code is `Vec<i32>::new()` which is invalid
+/// syntax. Ordinarily in handwritten Rust we would write `Vec::<i32>::new()`
+/// but for macros often the following is more convenient.
+///
+/// ```
+/// # use quote::quote;
+/// #
+/// # let field_type = quote!(...);
+/// #
+/// quote! {
+/// let value = <#field_type>::new();
+/// }
+/// # ;
+/// ```
+///
+/// This expands to `<Vec<i32>>::new()` which behaves correctly.
+///
+/// A similar pattern is appropriate for trait methods.
+///
+/// ```
+/// # use quote::quote;
+/// #
+/// # let field_type = quote!(...);
+/// #
+/// quote! {
+/// let value = <#field_type as core::default::Default>::default();
+/// }
+/// # ;
+/// ```
+///
+/// <p><br></p>
+///
+/// ### Interpolating text inside of doc comments
+///
+/// Neither doc comments nor string literals get interpolation behavior in
+/// quote:
+///
+/// ```compile_fail
+/// quote! {
+/// /// try to interpolate: #ident
+/// ///
+/// /// ...
+/// }
+/// ```
+///
+/// ```compile_fail
+/// quote! {
+/// #[doc = "try to interpolate: #ident"]
+/// }
+/// ```
+///
+/// Macro calls in a doc attribute are not valid syntax:
+///
+/// ```compile_fail
+/// quote! {
+/// #[doc = concat!("try to interpolate: ", stringify!(#ident))]
+/// }
+/// ```
+///
+/// Instead the best way to build doc comments that involve variables is by
+/// formatting the doc string literal outside of quote.
+///
+/// ```rust
+/// # use proc_macro2::{Ident, Span};
+/// # use quote::quote;
+/// #
+/// # const IGNORE: &str = stringify! {
+/// let msg = format!(...);
+/// # };
+/// #
+/// # let ident = Ident::new("var", Span::call_site());
+/// # let msg = format!("try to interpolate: {}", ident);
+/// quote! {
+/// #[doc = #msg]
+/// ///
+/// /// ...
+/// }
+/// # ;
+/// ```
+///
+/// <p><br></p>
+///
+/// ### Indexing into a tuple struct
+///
+/// When interpolating indices of a tuple or tuple struct, we need them not to
+/// appears suffixed as integer literals by interpolating them as [`syn::Index`]
+/// instead.
+///
+/// [`syn::Index`]: https://docs.rs/syn/1.0/syn/struct.Index.html
+///
+/// ```compile_fail
+/// let i = 0usize..self.fields.len();
+///
+/// // expands to 0 + self.0usize.heap_size() + self.1usize.heap_size() + ...
+/// // which is not valid syntax
+/// quote! {
+/// 0 #( + self.#i.heap_size() )*
+/// }
+/// ```
+///
+/// ```
+/// # use proc_macro2::{Ident, TokenStream};
+/// # use quote::quote;
+/// #
+/// # mod syn {
+/// # use proc_macro2::{Literal, TokenStream};
+/// # use quote::{ToTokens, TokenStreamExt};
+/// #
+/// # pub struct Index(usize);
+/// #
+/// # impl From<usize> for Index {
+/// # fn from(i: usize) -> Self {
+/// # Index(i)
+/// # }
+/// # }
+/// #
+/// # impl ToTokens for Index {
+/// # fn to_tokens(&self, tokens: &mut TokenStream) {
+/// # tokens.append(Literal::usize_unsuffixed(self.0));
+/// # }
+/// # }
+/// # }
+/// #
+/// # struct Struct {
+/// # fields: Vec<Ident>,
+/// # }
+/// #
+/// # impl Struct {
+/// # fn example(&self) -> TokenStream {
+/// let i = (0..self.fields.len()).map(syn::Index::from);
+///
+/// // expands to 0 + self.0.heap_size() + self.1.heap_size() + ...
+/// quote! {
+/// 0 #( + self.#i.heap_size() )*
+/// }
+/// # }
+/// # }
+/// ```
+#[macro_export]
+macro_rules! quote {
+ ($($tt:tt)*) => {
+ $crate::quote_spanned!($crate::__rt::Span::call_site()=> $($tt)*)
+ };
+}
+
+/// Same as `quote!`, but applies a given span to all tokens originating within
+/// the macro invocation.
+///
+/// <br>
+///
+/// # Syntax
+///
+/// A span expression of type [`Span`], followed by `=>`, followed by the tokens
+/// to quote. The span expression should be brief &mdash; use a variable for
+/// anything more than a few characters. There should be no space before the
+/// `=>` token.
+///
+/// [`Span`]: https://docs.rs/proc-macro2/1.0/proc_macro2/struct.Span.html
+///
+/// ```
+/// # use proc_macro2::Span;
+/// # use quote::quote_spanned;
+/// #
+/// # const IGNORE_TOKENS: &'static str = stringify! {
+/// let span = /* ... */;
+/// # };
+/// # let span = Span::call_site();
+/// # let init = 0;
+///
+/// // On one line, use parentheses.
+/// let tokens = quote_spanned!(span=> Box::into_raw(Box::new(#init)));
+///
+/// // On multiple lines, place the span at the top and use braces.
+/// let tokens = quote_spanned! {span=>
+/// Box::into_raw(Box::new(#init))
+/// };
+/// ```
+///
+/// The lack of space before the `=>` should look jarring to Rust programmers
+/// and this is intentional. The formatting is designed to be visibly
+/// off-balance and draw the eye a particular way, due to the span expression
+/// being evaluated in the context of the procedural macro and the remaining
+/// tokens being evaluated in the generated code.
+///
+/// <br>
+///
+/// # Hygiene
+///
+/// Any interpolated tokens preserve the `Span` information provided by their
+/// `ToTokens` implementation. Tokens that originate within the `quote_spanned!`
+/// invocation are spanned with the given span argument.
+///
+/// <br>
+///
+/// # Example
+///
+/// The following procedural macro code uses `quote_spanned!` to assert that a
+/// particular Rust type implements the [`Sync`] trait so that references can be
+/// safely shared between threads.
+///
+/// [`Sync`]: https://doc.rust-lang.org/std/marker/trait.Sync.html
+///
+/// ```
+/// # use quote::{quote_spanned, TokenStreamExt, ToTokens};
+/// # use proc_macro2::{Span, TokenStream};
+/// #
+/// # struct Type;
+/// #
+/// # impl Type {
+/// # fn span(&self) -> Span {
+/// # Span::call_site()
+/// # }
+/// # }
+/// #
+/// # impl ToTokens for Type {
+/// # fn to_tokens(&self, _tokens: &mut TokenStream) {}
+/// # }
+/// #
+/// # let ty = Type;
+/// # let call_site = Span::call_site();
+/// #
+/// let ty_span = ty.span();
+/// let assert_sync = quote_spanned! {ty_span=>
+/// struct _AssertSync where #ty: Sync;
+/// };
+/// ```
+///
+/// If the assertion fails, the user will see an error like the following. The
+/// input span of their type is hightlighted in the error.
+///
+/// ```text
+/// error[E0277]: the trait bound `*const (): std::marker::Sync` is not satisfied
+/// --> src/main.rs:10:21
+/// |
+/// 10 | static ref PTR: *const () = &();
+/// | ^^^^^^^^^ `*const ()` cannot be shared between threads safely
+/// ```
+///
+/// In this example it is important for the where-clause to be spanned with the
+/// line/column information of the user's input type so that error messages are
+/// placed appropriately by the compiler.
+#[macro_export]
+macro_rules! quote_spanned {
+ ($span:expr=> $($tt:tt)*) => {{
+ let mut _s = $crate::__rt::TokenStream::new();
+ let _span: $crate::__rt::Span = $span;
+ $crate::quote_each_token!(_s _span $($tt)*);
+ _s
+ }};
+}
+
+// Extract the names of all #metavariables and pass them to the $call macro.
+//
+// in: pounded_var_names!(then!(...) a #b c #( #d )* #e)
+// out: then!(... b);
+// then!(... d);
+// then!(... e);
+#[macro_export]
+#[doc(hidden)]
+macro_rules! pounded_var_names {
+ ($call:ident! $extra:tt $($tts:tt)*) => {
+ $crate::pounded_var_names_with_context!($call! $extra
+ (@ $($tts)*)
+ ($($tts)* @)
+ )
+ };
+}
+
+#[macro_export]
+#[doc(hidden)]
+macro_rules! pounded_var_names_with_context {
+ ($call:ident! $extra:tt ($($b1:tt)*) ($($curr:tt)*)) => {
+ $(
+ $crate::pounded_var_with_context!($call! $extra $b1 $curr);
+ )*
+ };
+}
+
+#[macro_export]
+#[doc(hidden)]
+macro_rules! pounded_var_with_context {
+ ($call:ident! $extra:tt $b1:tt ( $($inner:tt)* )) => {
+ $crate::pounded_var_names!($call! $extra $($inner)*);
+ };
+
+ ($call:ident! $extra:tt $b1:tt [ $($inner:tt)* ]) => {
+ $crate::pounded_var_names!($call! $extra $($inner)*);
+ };
+
+ ($call:ident! $extra:tt $b1:tt { $($inner:tt)* }) => {
+ $crate::pounded_var_names!($call! $extra $($inner)*);
+ };
+
+ ($call:ident!($($extra:tt)*) # $var:ident) => {
+ $crate::$call!($($extra)* $var);
+ };
+
+ ($call:ident! $extra:tt $b1:tt $curr:tt) => {};
+}
+
+#[macro_export]
+#[doc(hidden)]
+macro_rules! quote_bind_into_iter {
+ ($has_iter:ident $var:ident) => {
+ // `mut` may be unused if $var occurs multiple times in the list.
+ #[allow(unused_mut)]
+ let (mut $var, i) = $var.quote_into_iter();
+ let $has_iter = $has_iter | i;
+ };
+}
+
+#[macro_export]
+#[doc(hidden)]
+macro_rules! quote_bind_next_or_break {
+ ($var:ident) => {
+ let $var = match $var.next() {
+ Some(_x) => $crate::__rt::RepInterp(_x),
+ None => break,
+ };
+ };
+}
+
+#[macro_export]
+#[doc(hidden)]
+macro_rules! quote_each_token {
+ ($tokens:ident $span:ident $($tts:tt)*) => {
+ $crate::quote_tokens_with_context!($tokens $span
+ (@ @ @ @ @ @ $($tts)*)
+ (@ @ @ @ @ $($tts)* @)
+ (@ @ @ @ $($tts)* @ @)
+ (@ @ @ $(($tts))* @ @ @)
+ (@ @ $($tts)* @ @ @ @)
+ (@ $($tts)* @ @ @ @ @)
+ ($($tts)* @ @ @ @ @ @)
+ );
+ };
+}
+
+#[macro_export]
+#[doc(hidden)]
+macro_rules! quote_tokens_with_context {
+ ($tokens:ident $span:ident
+ ($($b3:tt)*) ($($b2:tt)*) ($($b1:tt)*)
+ ($($curr:tt)*)
+ ($($a1:tt)*) ($($a2:tt)*) ($($a3:tt)*)
+ ) => {
+ $(
+ $crate::quote_token_with_context!($tokens $span $b3 $b2 $b1 $curr $a1 $a2 $a3);
+ )*
+ };
+}
+
+#[macro_export]
+#[doc(hidden)]
+macro_rules! quote_token_with_context {
+ ($tokens:ident $span:ident $b3:tt $b2:tt $b1:tt @ $a1:tt $a2:tt $a3:tt) => {};
+
+ ($tokens:ident $span:ident $b3:tt $b2:tt $b1:tt (#) ( $($inner:tt)* ) * $a3:tt) => {{
+ use $crate::__rt::ext::*;
+ let has_iter = $crate::__rt::ThereIsNoIteratorInRepetition;
+ $crate::pounded_var_names!(quote_bind_into_iter!(has_iter) () $($inner)*);
+ let _: $crate::__rt::HasIterator = has_iter;
+ // This is `while true` instead of `loop` because if there are no
+ // iterators used inside of this repetition then the body would not
+ // contain any `break`, so the compiler would emit unreachable code
+ // warnings on anything below the loop. We use has_iter to detect and
+ // fail to compile when there are no iterators, so here we just work
+ // around the unneeded extra warning.
+ while true {
+ $crate::pounded_var_names!(quote_bind_next_or_break!() () $($inner)*);
+ $crate::quote_each_token!($tokens $span $($inner)*);
+ }
+ }};
+ ($tokens:ident $span:ident $b3:tt $b2:tt # (( $($inner:tt)* )) * $a2:tt $a3:tt) => {};
+ ($tokens:ident $span:ident $b3:tt # ( $($inner:tt)* ) (*) $a1:tt $a2:tt $a3:tt) => {};
+
+ ($tokens:ident $span:ident $b3:tt $b2:tt $b1:tt (#) ( $($inner:tt)* ) $sep:tt *) => {{
+ use $crate::__rt::ext::*;
+ let mut _i = 0usize;
+ let has_iter = $crate::__rt::ThereIsNoIteratorInRepetition;
+ $crate::pounded_var_names!(quote_bind_into_iter!(has_iter) () $($inner)*);
+ let _: $crate::__rt::HasIterator = has_iter;
+ while true {
+ $crate::pounded_var_names!(quote_bind_next_or_break!() () $($inner)*);
+ if _i > 0 {
+ $crate::quote_token!($tokens $span $sep);
+ }
+ _i += 1;
+ $crate::quote_each_token!($tokens $span $($inner)*);
+ }
+ }};
+ ($tokens:ident $span:ident $b3:tt $b2:tt # (( $($inner:tt)* )) $sep:tt * $a3:tt) => {};
+ ($tokens:ident $span:ident $b3:tt # ( $($inner:tt)* ) ($sep:tt) * $a2:tt $a3:tt) => {};
+ ($tokens:ident $span:ident # ( $($inner:tt)* ) * (*) $a1:tt $a2:tt $a3:tt) => {
+ // https://github.com/dtolnay/quote/issues/130
+ $crate::quote_token!($tokens $span *);
+ };
+ ($tokens:ident $span:ident # ( $($inner:tt)* ) $sep:tt (*) $a1:tt $a2:tt $a3:tt) => {};
+
+ ($tokens:ident $span:ident $b3:tt $b2:tt $b1:tt (#) $var:ident $a2:tt $a3:tt) => {
+ $crate::ToTokens::to_tokens(&$var, &mut $tokens);
+ };
+ ($tokens:ident $span:ident $b3:tt $b2:tt # ($var:ident) $a1:tt $a2:tt $a3:tt) => {};
+ ($tokens:ident $span:ident $b3:tt $b2:tt $b1:tt ($curr:tt) $a1:tt $a2:tt $a3:tt) => {
+ $crate::quote_token!($tokens $span $curr);
+ };
+}
+
+#[macro_export]
+#[doc(hidden)]
+macro_rules! quote_token {
+ ($tokens:ident $span:ident ( $($inner:tt)* )) => {
+ $tokens.extend({
+ let mut g = $crate::__rt::Group::new(
+ $crate::__rt::Delimiter::Parenthesis,
+ $crate::quote_spanned!($span=> $($inner)*),
+ );
+ g.set_span($span);
+ Some($crate::__rt::TokenTree::from(g))
+ });
+ };
+
+ ($tokens:ident $span:ident [ $($inner:tt)* ]) => {
+ $tokens.extend({
+ let mut g = $crate::__rt::Group::new(
+ $crate::__rt::Delimiter::Bracket,
+ $crate::quote_spanned!($span=> $($inner)*),
+ );
+ g.set_span($span);
+ Some($crate::__rt::TokenTree::from(g))
+ });
+ };
+
+ ($tokens:ident $span:ident { $($inner:tt)* }) => {
+ $tokens.extend({
+ let mut g = $crate::__rt::Group::new(
+ $crate::__rt::Delimiter::Brace,
+ $crate::quote_spanned!($span=> $($inner)*),
+ );
+ g.set_span($span);
+ Some($crate::__rt::TokenTree::from(g))
+ });
+ };
+
+ ($tokens:ident $span:ident +) => {
+ $crate::__rt::push_add(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident +=) => {
+ $crate::__rt::push_add_eq(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident &) => {
+ $crate::__rt::push_and(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident &&) => {
+ $crate::__rt::push_and_and(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident &=) => {
+ $crate::__rt::push_and_eq(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident @) => {
+ $crate::__rt::push_at(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident !) => {
+ $crate::__rt::push_bang(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident ^) => {
+ $crate::__rt::push_caret(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident ^=) => {
+ $crate::__rt::push_caret_eq(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident :) => {
+ $crate::__rt::push_colon(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident ::) => {
+ $crate::__rt::push_colon2(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident ,) => {
+ $crate::__rt::push_comma(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident /) => {
+ $crate::__rt::push_div(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident /=) => {
+ $crate::__rt::push_div_eq(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident .) => {
+ $crate::__rt::push_dot(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident ..) => {
+ $crate::__rt::push_dot2(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident ...) => {
+ $crate::__rt::push_dot3(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident ..=) => {
+ $crate::__rt::push_dot_dot_eq(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident =) => {
+ $crate::__rt::push_eq(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident ==) => {
+ $crate::__rt::push_eq_eq(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident >=) => {
+ $crate::__rt::push_ge(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident >) => {
+ $crate::__rt::push_gt(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident <=) => {
+ $crate::__rt::push_le(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident <) => {
+ $crate::__rt::push_lt(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident *=) => {
+ $crate::__rt::push_mul_eq(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident !=) => {
+ $crate::__rt::push_ne(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident |) => {
+ $crate::__rt::push_or(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident |=) => {
+ $crate::__rt::push_or_eq(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident ||) => {
+ $crate::__rt::push_or_or(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident #) => {
+ $crate::__rt::push_pound(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident ?) => {
+ $crate::__rt::push_question(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident ->) => {
+ $crate::__rt::push_rarrow(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident <-) => {
+ $crate::__rt::push_larrow(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident %) => {
+ $crate::__rt::push_rem(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident %=) => {
+ $crate::__rt::push_rem_eq(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident =>) => {
+ $crate::__rt::push_fat_arrow(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident ;) => {
+ $crate::__rt::push_semi(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident <<) => {
+ $crate::__rt::push_shl(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident <<=) => {
+ $crate::__rt::push_shl_eq(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident >>) => {
+ $crate::__rt::push_shr(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident >>=) => {
+ $crate::__rt::push_shr_eq(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident *) => {
+ $crate::__rt::push_star(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident -) => {
+ $crate::__rt::push_sub(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident -=) => {
+ $crate::__rt::push_sub_eq(&mut $tokens, $span);
+ };
+
+ ($tokens:ident $span:ident $other:tt) => {
+ $crate::__rt::parse(&mut $tokens, $span, stringify!($other));
+ };
+}
diff --git a/quote/src/runtime.rs b/quote/src/runtime.rs
new file mode 100644
index 0000000..4a1c14c
--- /dev/null
+++ b/quote/src/runtime.rs
@@ -0,0 +1,373 @@
+use crate::{IdentFragment, ToTokens, TokenStreamExt};
+use std::fmt;
+use std::ops::BitOr;
+
+pub use proc_macro2::*;
+
+pub struct HasIterator; // True
+pub struct ThereIsNoIteratorInRepetition; // False
+
+impl BitOr<ThereIsNoIteratorInRepetition> for ThereIsNoIteratorInRepetition {
+ type Output = ThereIsNoIteratorInRepetition;
+ fn bitor(self, _rhs: ThereIsNoIteratorInRepetition) -> ThereIsNoIteratorInRepetition {
+ ThereIsNoIteratorInRepetition
+ }
+}
+
+impl BitOr<ThereIsNoIteratorInRepetition> for HasIterator {
+ type Output = HasIterator;
+ fn bitor(self, _rhs: ThereIsNoIteratorInRepetition) -> HasIterator {
+ HasIterator
+ }
+}
+
+impl BitOr<HasIterator> for ThereIsNoIteratorInRepetition {
+ type Output = HasIterator;
+ fn bitor(self, _rhs: HasIterator) -> HasIterator {
+ HasIterator
+ }
+}
+
+impl BitOr<HasIterator> for HasIterator {
+ type Output = HasIterator;
+ fn bitor(self, _rhs: HasIterator) -> HasIterator {
+ HasIterator
+ }
+}
+
+/// Extension traits used by the implementation of `quote!`. These are defined
+/// in separate traits, rather than as a single trait due to ambiguity issues.
+///
+/// These traits expose a `quote_into_iter` method which should allow calling
+/// whichever impl happens to be applicable. Calling that method repeatedly on
+/// the returned value should be idempotent.
+pub mod ext {
+ use super::RepInterp;
+ use super::{HasIterator as HasIter, ThereIsNoIteratorInRepetition as DoesNotHaveIter};
+ use crate::ToTokens;
+ use std::collections::btree_set::{self, BTreeSet};
+ use std::slice;
+
+ /// Extension trait providing the `quote_into_iter` method on iterators.
+ pub trait RepIteratorExt: Iterator + Sized {
+ fn quote_into_iter(self) -> (Self, HasIter) {
+ (self, HasIter)
+ }
+ }
+
+ impl<T: Iterator> RepIteratorExt for T {}
+
+ /// Extension trait providing the `quote_into_iter` method for
+ /// non-iterable types. These types interpolate the same value in each
+ /// iteration of the repetition.
+ pub trait RepToTokensExt {
+ /// Pretend to be an iterator for the purposes of `quote_into_iter`.
+ /// This allows repeated calls to `quote_into_iter` to continue
+ /// correctly returning DoesNotHaveIter.
+ fn next(&self) -> Option<&Self> {
+ Some(self)
+ }
+
+ fn quote_into_iter(&self) -> (&Self, DoesNotHaveIter) {
+ (self, DoesNotHaveIter)
+ }
+ }
+
+ impl<T: ToTokens + ?Sized> RepToTokensExt for T {}
+
+ /// Extension trait providing the `quote_into_iter` method for types that
+ /// can be referenced as an iterator.
+ pub trait RepAsIteratorExt<'q> {
+ type Iter: Iterator;
+
+ fn quote_into_iter(&'q self) -> (Self::Iter, HasIter);
+ }
+
+ impl<'q, 'a, T: RepAsIteratorExt<'q> + ?Sized> RepAsIteratorExt<'q> for &'a T {
+ type Iter = T::Iter;
+
+ fn quote_into_iter(&'q self) -> (Self::Iter, HasIter) {
+ <T as RepAsIteratorExt>::quote_into_iter(*self)
+ }
+ }
+
+ impl<'q, 'a, T: RepAsIteratorExt<'q> + ?Sized> RepAsIteratorExt<'q> for &'a mut T {
+ type Iter = T::Iter;
+
+ fn quote_into_iter(&'q self) -> (Self::Iter, HasIter) {
+ <T as RepAsIteratorExt>::quote_into_iter(*self)
+ }
+ }
+
+ impl<'q, T: 'q> RepAsIteratorExt<'q> for [T] {
+ type Iter = slice::Iter<'q, T>;
+
+ fn quote_into_iter(&'q self) -> (Self::Iter, HasIter) {
+ (self.iter(), HasIter)
+ }
+ }
+
+ impl<'q, T: 'q> RepAsIteratorExt<'q> for Vec<T> {
+ type Iter = slice::Iter<'q, T>;
+
+ fn quote_into_iter(&'q self) -> (Self::Iter, HasIter) {
+ (self.iter(), HasIter)
+ }
+ }
+
+ impl<'q, T: 'q> RepAsIteratorExt<'q> for BTreeSet<T> {
+ type Iter = btree_set::Iter<'q, T>;
+
+ fn quote_into_iter(&'q self) -> (Self::Iter, HasIter) {
+ (self.iter(), HasIter)
+ }
+ }
+
+ macro_rules! array_rep_slice {
+ ($($l:tt)*) => {
+ $(
+ impl<'q, T: 'q> RepAsIteratorExt<'q> for [T; $l] {
+ type Iter = slice::Iter<'q, T>;
+
+ fn quote_into_iter(&'q self) -> (Self::Iter, HasIter) {
+ (self.iter(), HasIter)
+ }
+ }
+ )*
+ }
+ }
+
+ array_rep_slice!(
+ 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
+ 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
+ );
+
+ impl<'q, T: RepAsIteratorExt<'q>> RepAsIteratorExt<'q> for RepInterp<T> {
+ type Iter = T::Iter;
+
+ fn quote_into_iter(&'q self) -> (Self::Iter, HasIter) {
+ self.0.quote_into_iter()
+ }
+ }
+}
+
+// Helper type used within interpolations to allow for repeated binding names.
+// Implements the relevant traits, and exports a dummy `next()` method.
+#[derive(Copy, Clone)]
+pub struct RepInterp<T>(pub T);
+
+impl<T> RepInterp<T> {
+ // This method is intended to look like `Iterator::next`, and is called when
+ // a name is bound multiple times, as the previous binding will shadow the
+ // original `Iterator` object. This allows us to avoid advancing the
+ // iterator multiple times per iteration.
+ pub fn next(self) -> Option<T> {
+ Some(self.0)
+ }
+}
+
+impl<T: Iterator> Iterator for RepInterp<T> {
+ type Item = T::Item;
+
+ fn next(&mut self) -> Option<Self::Item> {
+ self.0.next()
+ }
+}
+
+impl<T: ToTokens> ToTokens for RepInterp<T> {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ self.0.to_tokens(tokens);
+ }
+}
+
+fn is_ident_start(c: u8) -> bool {
+ (b'a' <= c && c <= b'z') || (b'A' <= c && c <= b'Z') || c == b'_'
+}
+
+fn is_ident_continue(c: u8) -> bool {
+ (b'a' <= c && c <= b'z') || (b'A' <= c && c <= b'Z') || c == b'_' || (b'0' <= c && c <= b'9')
+}
+
+fn is_ident(token: &str) -> bool {
+ let mut iter = token.bytes();
+ let first_ok = iter.next().map(is_ident_start).unwrap_or(false);
+
+ first_ok && iter.all(is_ident_continue)
+}
+
+pub fn parse(tokens: &mut TokenStream, span: Span, s: &str) {
+ if is_ident(s) {
+ // Fast path, since idents are the most common token.
+ tokens.append(Ident::new(s, span));
+ } else {
+ let s: TokenStream = s.parse().expect("invalid token stream");
+ tokens.extend(s.into_iter().map(|mut t| {
+ t.set_span(span);
+ t
+ }));
+ }
+}
+
+macro_rules! push_punct {
+ ($name:ident $char1:tt) => {
+ pub fn $name(tokens: &mut TokenStream, span: Span) {
+ let mut punct = Punct::new($char1, Spacing::Alone);
+ punct.set_span(span);
+ tokens.append(punct);
+ }
+ };
+ ($name:ident $char1:tt $char2:tt) => {
+ pub fn $name(tokens: &mut TokenStream, span: Span) {
+ let mut punct = Punct::new($char1, Spacing::Joint);
+ punct.set_span(span);
+ tokens.append(punct);
+ let mut punct = Punct::new($char2, Spacing::Alone);
+ punct.set_span(span);
+ tokens.append(punct);
+ }
+ };
+ ($name:ident $char1:tt $char2:tt $char3:tt) => {
+ pub fn $name(tokens: &mut TokenStream, span: Span) {
+ let mut punct = Punct::new($char1, Spacing::Joint);
+ punct.set_span(span);
+ tokens.append(punct);
+ let mut punct = Punct::new($char2, Spacing::Joint);
+ punct.set_span(span);
+ tokens.append(punct);
+ let mut punct = Punct::new($char3, Spacing::Alone);
+ punct.set_span(span);
+ tokens.append(punct);
+ }
+ };
+}
+
+push_punct!(push_add '+');
+push_punct!(push_add_eq '+' '=');
+push_punct!(push_and '&');
+push_punct!(push_and_and '&' '&');
+push_punct!(push_and_eq '&' '=');
+push_punct!(push_at '@');
+push_punct!(push_bang '!');
+push_punct!(push_caret '^');
+push_punct!(push_caret_eq '^' '=');
+push_punct!(push_colon ':');
+push_punct!(push_colon2 ':' ':');
+push_punct!(push_comma ',');
+push_punct!(push_div '/');
+push_punct!(push_div_eq '/' '=');
+push_punct!(push_dot '.');
+push_punct!(push_dot2 '.' '.');
+push_punct!(push_dot3 '.' '.' '.');
+push_punct!(push_dot_dot_eq '.' '.' '=');
+push_punct!(push_eq '=');
+push_punct!(push_eq_eq '=' '=');
+push_punct!(push_ge '>' '=');
+push_punct!(push_gt '>');
+push_punct!(push_le '<' '=');
+push_punct!(push_lt '<');
+push_punct!(push_mul_eq '*' '=');
+push_punct!(push_ne '!' '=');
+push_punct!(push_or '|');
+push_punct!(push_or_eq '|' '=');
+push_punct!(push_or_or '|' '|');
+push_punct!(push_pound '#');
+push_punct!(push_question '?');
+push_punct!(push_rarrow '-' '>');
+push_punct!(push_larrow '<' '-');
+push_punct!(push_rem '%');
+push_punct!(push_rem_eq '%' '=');
+push_punct!(push_fat_arrow '=' '>');
+push_punct!(push_semi ';');
+push_punct!(push_shl '<' '<');
+push_punct!(push_shl_eq '<' '<' '=');
+push_punct!(push_shr '>' '>');
+push_punct!(push_shr_eq '>' '>' '=');
+push_punct!(push_star '*');
+push_punct!(push_sub '-');
+push_punct!(push_sub_eq '-' '=');
+
+// Helper method for constructing identifiers from the `format_ident!` macro,
+// handling `r#` prefixes.
+//
+// Directly parsing the input string may produce a valid identifier,
+// although the input string was invalid, due to ignored characters such as
+// whitespace and comments. Instead, we always create a non-raw identifier
+// to validate that the string is OK, and only parse again if needed.
+//
+// The `is_ident` method defined above is insufficient for validation, as it
+// will reject non-ASCII identifiers.
+pub fn mk_ident(id: &str, span: Option<Span>) -> Ident {
+ let span = span.unwrap_or_else(Span::call_site);
+
+ let is_raw = id.starts_with("r#");
+ let unraw = Ident::new(if is_raw { &id[2..] } else { id }, span);
+ if !is_raw {
+ return unraw;
+ }
+
+ // At this point, the identifier is raw, and the unraw-ed version of it was
+ // successfully converted into an identifier. Try to produce a valid raw
+ // identifier by running the `TokenStream` parser, and unwrapping the first
+ // token as an `Ident`.
+ //
+ // FIXME: When `Ident::new_raw` becomes stable, this method should be
+ // updated to call it when available.
+ match id.parse::<TokenStream>() {
+ Ok(ts) => {
+ let mut iter = ts.into_iter();
+ match (iter.next(), iter.next()) {
+ (Some(TokenTree::Ident(mut id)), None) => {
+ id.set_span(span);
+ id
+ }
+ _ => unreachable!("valid raw ident fails to parse"),
+ }
+ }
+ Err(_) => unreachable!("valid raw ident fails to parse"),
+ }
+}
+
+// Adapts from `IdentFragment` to `fmt::Display` for use by the `format_ident!`
+// macro, and exposes span information from these fragments.
+//
+// This struct also has forwarding implementations of the formatting traits
+// `Octal`, `LowerHex`, `UpperHex`, and `Binary` to allow for their use within
+// `format_ident!`.
+#[derive(Copy, Clone)]
+pub struct IdentFragmentAdapter<T: IdentFragment>(pub T);
+
+impl<T: IdentFragment> IdentFragmentAdapter<T> {
+ pub fn span(&self) -> Option<Span> {
+ self.0.span()
+ }
+}
+
+impl<T: IdentFragment> fmt::Display for IdentFragmentAdapter<T> {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ IdentFragment::fmt(&self.0, f)
+ }
+}
+
+impl<T: IdentFragment + fmt::Octal> fmt::Octal for IdentFragmentAdapter<T> {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ fmt::Octal::fmt(&self.0, f)
+ }
+}
+
+impl<T: IdentFragment + fmt::LowerHex> fmt::LowerHex for IdentFragmentAdapter<T> {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ fmt::LowerHex::fmt(&self.0, f)
+ }
+}
+
+impl<T: IdentFragment + fmt::UpperHex> fmt::UpperHex for IdentFragmentAdapter<T> {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ fmt::UpperHex::fmt(&self.0, f)
+ }
+}
+
+impl<T: IdentFragment + fmt::Binary> fmt::Binary for IdentFragmentAdapter<T> {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ fmt::Binary::fmt(&self.0, f)
+ }
+}
diff --git a/quote/src/spanned.rs b/quote/src/spanned.rs
new file mode 100644
index 0000000..55168bd
--- /dev/null
+++ b/quote/src/spanned.rs
@@ -0,0 +1,42 @@
+use crate::ToTokens;
+use proc_macro2::{Span, TokenStream};
+
+pub trait Spanned {
+ fn __span(&self) -> Span;
+}
+
+impl Spanned for Span {
+ fn __span(&self) -> Span {
+ *self
+ }
+}
+
+impl<T: ?Sized + ToTokens> Spanned for T {
+ fn __span(&self) -> Span {
+ join_spans(self.into_token_stream())
+ }
+}
+
+fn join_spans(tokens: TokenStream) -> Span {
+ let mut iter = tokens.into_iter().filter_map(|tt| {
+ // FIXME: This shouldn't be required, since optimally spans should
+ // never be invalid. This filter_map can probably be removed when
+ // https://github.com/rust-lang/rust/issues/43081 is resolved.
+ let span = tt.span();
+ let debug = format!("{:?}", span);
+ if debug.ends_with("bytes(0..0)") {
+ None
+ } else {
+ Some(span)
+ }
+ });
+
+ let first = match iter.next() {
+ Some(span) => span,
+ None => return Span::call_site(),
+ };
+
+ iter.fold(None, |_prev, next| Some(next))
+ .and_then(|last| first.join(last))
+ .unwrap_or(first)
+}
diff --git a/quote/src/to_tokens.rs b/quote/src/to_tokens.rs
new file mode 100644
index 0000000..7f98083
--- /dev/null
+++ b/quote/src/to_tokens.rs
@@ -0,0 +1,209 @@
+use super::TokenStreamExt;
+
+use std::borrow::Cow;
+use std::iter;
+use std::rc::Rc;
+
+use proc_macro2::{Group, Ident, Literal, Punct, Span, TokenStream, TokenTree};
+
+/// Types that can be interpolated inside a `quote!` invocation.
+///
+/// [`quote!`]: macro.quote.html
+pub trait ToTokens {
+ /// Write `self` to the given `TokenStream`.
+ ///
+ /// The token append methods provided by the [`TokenStreamExt`] extension
+ /// trait may be useful for implementing `ToTokens`.
+ ///
+ /// [`TokenStreamExt`]: trait.TokenStreamExt.html
+ ///
+ /// # Example
+ ///
+ /// Example implementation for a struct representing Rust paths like
+ /// `std::cmp::PartialEq`:
+ ///
+ /// ```
+ /// use proc_macro2::{TokenTree, Spacing, Span, Punct, TokenStream};
+ /// use quote::{TokenStreamExt, ToTokens};
+ ///
+ /// pub struct Path {
+ /// pub global: bool,
+ /// pub segments: Vec<PathSegment>,
+ /// }
+ ///
+ /// impl ToTokens for Path {
+ /// fn to_tokens(&self, tokens: &mut TokenStream) {
+ /// for (i, segment) in self.segments.iter().enumerate() {
+ /// if i > 0 || self.global {
+ /// // Double colon `::`
+ /// tokens.append(Punct::new(':', Spacing::Joint));
+ /// tokens.append(Punct::new(':', Spacing::Alone));
+ /// }
+ /// segment.to_tokens(tokens);
+ /// }
+ /// }
+ /// }
+ /// #
+ /// # pub struct PathSegment;
+ /// #
+ /// # impl ToTokens for PathSegment {
+ /// # fn to_tokens(&self, tokens: &mut TokenStream) {
+ /// # unimplemented!()
+ /// # }
+ /// # }
+ /// ```
+ fn to_tokens(&self, tokens: &mut TokenStream);
+
+ /// Convert `self` directly into a `TokenStream` object.
+ ///
+ /// This method is implicitly implemented using `to_tokens`, and acts as a
+ /// convenience method for consumers of the `ToTokens` trait.
+ fn to_token_stream(&self) -> TokenStream {
+ let mut tokens = TokenStream::new();
+ self.to_tokens(&mut tokens);
+ tokens
+ }
+
+ /// Convert `self` directly into a `TokenStream` object.
+ ///
+ /// This method is implicitly implemented using `to_tokens`, and acts as a
+ /// convenience method for consumers of the `ToTokens` trait.
+ fn into_token_stream(self) -> TokenStream
+ where
+ Self: Sized,
+ {
+ self.to_token_stream()
+ }
+}
+
+impl<'a, T: ?Sized + ToTokens> ToTokens for &'a T {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ (**self).to_tokens(tokens);
+ }
+}
+
+impl<'a, T: ?Sized + ToTokens> ToTokens for &'a mut T {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ (**self).to_tokens(tokens);
+ }
+}
+
+impl<'a, T: ?Sized + ToOwned + ToTokens> ToTokens for Cow<'a, T> {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ (**self).to_tokens(tokens);
+ }
+}
+
+impl<T: ?Sized + ToTokens> ToTokens for Box<T> {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ (**self).to_tokens(tokens);
+ }
+}
+
+impl<T: ?Sized + ToTokens> ToTokens for Rc<T> {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ (**self).to_tokens(tokens);
+ }
+}
+
+impl<T: ToTokens> ToTokens for Option<T> {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ if let Some(ref t) = *self {
+ t.to_tokens(tokens);
+ }
+ }
+}
+
+impl ToTokens for str {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(Literal::string(self));
+ }
+}
+
+impl ToTokens for String {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ self.as_str().to_tokens(tokens);
+ }
+}
+
+macro_rules! primitive {
+ ($($t:ident => $name:ident)*) => ($(
+ impl ToTokens for $t {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(Literal::$name(*self));
+ }
+ }
+ )*)
+}
+
+primitive! {
+ i8 => i8_suffixed
+ i16 => i16_suffixed
+ i32 => i32_suffixed
+ i64 => i64_suffixed
+ i128 => i128_suffixed
+ isize => isize_suffixed
+
+ u8 => u8_suffixed
+ u16 => u16_suffixed
+ u32 => u32_suffixed
+ u64 => u64_suffixed
+ u128 => u128_suffixed
+ usize => usize_suffixed
+
+ f32 => f32_suffixed
+ f64 => f64_suffixed
+}
+
+impl ToTokens for char {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(Literal::character(*self));
+ }
+}
+
+impl ToTokens for bool {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ let word = if *self { "true" } else { "false" };
+ tokens.append(Ident::new(word, Span::call_site()));
+ }
+}
+
+impl ToTokens for Group {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(self.clone());
+ }
+}
+
+impl ToTokens for Ident {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(self.clone());
+ }
+}
+
+impl ToTokens for Punct {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(self.clone());
+ }
+}
+
+impl ToTokens for Literal {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.append(self.clone());
+ }
+}
+
+impl ToTokens for TokenTree {
+ fn to_tokens(&self, dst: &mut TokenStream) {
+ dst.append(self.clone());
+ }
+}
+
+impl ToTokens for TokenStream {
+ fn to_tokens(&self, dst: &mut TokenStream) {
+ dst.extend(iter::once(self.clone()));
+ }
+
+ fn into_token_stream(self) -> TokenStream {
+ self
+ }
+}