Vendor dependencies for 0.3.0 release

vendor/bevy_macro_utils/src/attrs.rs

@@ -0,0 +1,34 @@
+use syn::{Expr, ExprLit, Lit};
+
+use crate::symbol::Symbol;
+
+/// Get a [literal string](struct@syn::LitStr) from the provided [expression](Expr).
+pub fn get_lit_str(attr_name: Symbol, value: &Expr) -> syn::Result<&syn::LitStr> {
+    if let Expr::Lit(ExprLit {
+        lit: Lit::Str(lit), ..
+    }) = &value
+    {
+        Ok(lit)
+    } else {
+        Err(syn::Error::new_spanned(
+            value,
+            format!("expected {attr_name} attribute to be a string: `{attr_name} = \"...\"`"),
+        ))
+    }
+}
+
+/// Get a [literal boolean](struct@syn::LitBool) from the provided [expression](Expr) as a [`bool`].
+pub fn get_lit_bool(attr_name: Symbol, value: &Expr) -> syn::Result<bool> {
+    if let Expr::Lit(ExprLit {
+        lit: Lit::Bool(lit),
+        ..
+    }) = &value
+    {
+        Ok(lit.value())
+    } else {
+        Err(syn::Error::new_spanned(
+            value,
+            format!("expected {attr_name} attribute to be a bool value, `true` or `false`: `{attr_name} = ...`"),
+        ))?
+    }
+}