Vendor dependencies

Let's see how I like this workflow.

vendor/syn/src/custom_keyword.rs

@@ -0,0 +1,253 @@
+/// Define a type that supports parsing and printing a given identifier as if it
+/// were a keyword.
+///
+/// # Usage
+///
+/// As a convention, it is recommended that this macro be invoked within a
+/// module called `kw` or `keyword` and that the resulting parser be invoked
+/// with a `kw::` or `keyword::` prefix.
+///
+/// ```
+/// mod kw {
+///     syn::custom_keyword!(whatever);
+/// }
+/// ```
+///
+/// The generated syntax tree node supports the following operations just like
+/// any built-in keyword token.
+///
+/// - [Peeking] — `input.peek(kw::whatever)`
+///
+/// - [Parsing] — `input.parse::<kw::whatever>()?`
+///
+/// - [Printing] — `quote!( ... #whatever_token ... )`
+///
+/// - Construction from a [`Span`] — `let whatever_token = kw::whatever(sp)`
+///
+/// - Field access to its span — `let sp = whatever_token.span`
+///
+/// [Peeking]: crate::parse::ParseBuffer::peek
+/// [Parsing]: crate::parse::ParseBuffer::parse
+/// [Printing]: quote::ToTokens
+/// [`Span`]: proc_macro2::Span
+///
+/// # Example
+///
+/// This example parses input that looks like `bool = true` or `str = "value"`.
+/// The key must be either the identifier `bool` or the identifier `str`. If
+/// `bool`, the value may be either `true` or `false`. If `str`, the value may
+/// be any string literal.
+///
+/// The symbols `bool` and `str` are not reserved keywords in Rust so these are
+/// not considered keywords in the `syn::token` module. Like any other
+/// identifier that is not a keyword, these can be declared as custom keywords
+/// by crates that need to use them as such.
+///
+/// ```
+/// use syn::{LitBool, LitStr, Result, Token};
+/// use syn::parse::{Parse, ParseStream};
+///
+/// mod kw {
+///     syn::custom_keyword!(bool);
+///     syn::custom_keyword!(str);
+/// }
+///
+/// enum Argument {
+///     Bool {
+///         bool_token: kw::bool,
+///         eq_token: Token![=],
+///         value: LitBool,
+///     },
+///     Str {
+///         str_token: kw::str,
+///         eq_token: Token![=],
+///         value: LitStr,
+///     },
+/// }
+///
+/// impl Parse for Argument {
+///     fn parse(input: ParseStream) -> Result<Self> {
+///         let lookahead = input.lookahead1();
+///         if lookahead.peek(kw::bool) {
+///             Ok(Argument::Bool {
+///                 bool_token: input.parse::<kw::bool>()?,
+///                 eq_token: input.parse()?,
+///                 value: input.parse()?,
+///             })
+///         } else if lookahead.peek(kw::str) {
+///             Ok(Argument::Str {
+///                 str_token: input.parse::<kw::str>()?,
+///                 eq_token: input.parse()?,
+///                 value: input.parse()?,
+///             })
+///         } else {
+///             Err(lookahead.error())
+///         }
+///     }
+/// }
+/// ```
+#[macro_export]
+macro_rules! custom_keyword {
+    ($ident:ident) => {
+        #[allow(non_camel_case_types)]
+        pub struct $ident {
+            pub span: $crate::__private::Span,
+        }
+
+        #[doc(hidden)]
+        #[allow(dead_code, non_snake_case)]
+        pub fn $ident<__S: $crate::__private::IntoSpans<[$crate::__private::Span; 1]>>(
+            span: __S,
+        ) -> $ident {
+            $ident {
+                span: $crate::__private::IntoSpans::into_spans(span)[0],
+            }
+        }
+
+        impl $crate::__private::Default for $ident {
+            fn default() -> Self {
+                $ident {
+                    span: $crate::__private::Span::call_site(),
+                }
+            }
+        }
+
+        $crate::impl_parse_for_custom_keyword!($ident);
+        $crate::impl_to_tokens_for_custom_keyword!($ident);
+        $crate::impl_clone_for_custom_keyword!($ident);
+        $crate::impl_extra_traits_for_custom_keyword!($ident);
+    };
+}
+
+// Not public API.
+#[cfg(feature = "parsing")]
+#[doc(hidden)]
+#[macro_export]
+macro_rules! impl_parse_for_custom_keyword {
+    ($ident:ident) => {
+        // For peek.
+        impl $crate::token::CustomToken for $ident {
+            fn peek(cursor: $crate::buffer::Cursor) -> $crate::__private::bool {
+                if let $crate::__private::Some((ident, _rest)) = cursor.ident() {
+                    ident == stringify!($ident)
+                } else {
+                    false
+                }
+            }
+
+            fn display() -> &'static $crate::__private::str {
+                concat!("`", stringify!($ident), "`")
+            }
+        }
+
+        impl $crate::parse::Parse for $ident {
+            fn parse(input: $crate::parse::ParseStream) -> $crate::parse::Result<$ident> {
+                input.step(|cursor| {
+                    if let $crate::__private::Some((ident, rest)) = cursor.ident() {
+                        if ident == stringify!($ident) {
+                            return $crate::__private::Ok(($ident { span: ident.span() }, rest));
+                        }
+                    }
+                    $crate::__private::Err(cursor.error(concat!(
+                        "expected `",
+                        stringify!($ident),
+                        "`"
+                    )))
+                })
+            }
+        }
+    };
+}
+
+// Not public API.
+#[cfg(not(feature = "parsing"))]
+#[doc(hidden)]
+#[macro_export]
+macro_rules! impl_parse_for_custom_keyword {
+    ($ident:ident) => {};
+}
+
+// Not public API.
+#[cfg(feature = "printing")]
+#[doc(hidden)]
+#[macro_export]
+macro_rules! impl_to_tokens_for_custom_keyword {
+    ($ident:ident) => {
+        impl $crate::__private::ToTokens for $ident {
+            fn to_tokens(&self, tokens: &mut $crate::__private::TokenStream2) {
+                let ident = $crate::Ident::new(stringify!($ident), self.span);
+                $crate::__private::TokenStreamExt::append(tokens, ident);
+            }
+        }
+    };
+}
+
+// Not public API.
+#[cfg(not(feature = "printing"))]
+#[doc(hidden)]
+#[macro_export]
+macro_rules! impl_to_tokens_for_custom_keyword {
+    ($ident:ident) => {};
+}
+
+// Not public API.
+#[cfg(feature = "clone-impls")]
+#[doc(hidden)]
+#[macro_export]
+macro_rules! impl_clone_for_custom_keyword {
+    ($ident:ident) => {
+        impl $crate::__private::Copy for $ident {}
+
+        #[allow(clippy::expl_impl_clone_on_copy)]
+        impl $crate::__private::Clone for $ident {
+            fn clone(&self) -> Self {
+                *self
+            }
+        }
+    };
+}
+
+// Not public API.
+#[cfg(not(feature = "clone-impls"))]
+#[doc(hidden)]
+#[macro_export]
+macro_rules! impl_clone_for_custom_keyword {
+    ($ident:ident) => {};
+}
+
+// Not public API.
+#[cfg(feature = "extra-traits")]
+#[doc(hidden)]
+#[macro_export]
+macro_rules! impl_extra_traits_for_custom_keyword {
+    ($ident:ident) => {
+        impl $crate::__private::Debug for $ident {
+            fn fmt(&self, f: &mut $crate::__private::Formatter) -> $crate::__private::fmt::Result {
+                $crate::__private::Formatter::write_str(
+                    f,
+                    concat!("Keyword [", stringify!($ident), "]"),
+                )
+            }
+        }
+
+        impl $crate::__private::Eq for $ident {}
+
+        impl $crate::__private::PartialEq for $ident {
+            fn eq(&self, _other: &Self) -> $crate::__private::bool {
+                true
+            }
+        }
+
+        impl $crate::__private::Hash for $ident {
+            fn hash<__H: $crate::__private::Hasher>(&self, _state: &mut __H) {}
+        }
+    };
+}
+
+// Not public API.
+#[cfg(not(feature = "extra-traits"))]
+#[doc(hidden)]
+#[macro_export]
+macro_rules! impl_extra_traits_for_custom_keyword {
+    ($ident:ident) => {};
+}