feat(es/quote): Allow using Str as a var (#6797)

crates/swc_ecma_quote/src/lib.rs

@@ -46,12 +46,13 @@ mod clone;
 /// ## Typed variables
 ///
 /// As this macro generates static AST, it can't substitute variables if an
-/// ideitifier is not allowed in such position. In other words, this macro only
+/// identifier is not allowed in such position. In other words, this macro only
 /// supports substituting
 ///
-///  - Ident
-///  - Expr
-///  - Pat
+///  - [swc_ecma_ast::Ident]
+///  - [swc_ecma_ast::Expr]
+///  - [swc_ecma_ast::Pat]
+///  - [swc_ecma_ast::Str]
 ///
 /// You can use it like
 ///
@@ -82,6 +83,22 @@ mod clone;
 ///
 /// // Tip: Use private_ident!("ref") for real identifiers.
 /// ```
+///
+/// ## Using `Str`
+///
+/// The grammar is `"$var_name"`.
+///
+/// ```rust
+/// use swc_common::DUMMY_SP;
+/// use swc_ecma_ast::Str;
+/// use swc_ecma_quote::quote;
+///
+/// // This will return ast for `import thing from "foo";`
+/// let _stmt = quote!(
+///                 "import thing from \"$thing\";" as ModuleItem,
+///                 thing: Str = "foo".into(),
+///             );
+/// ```
 #[macro_export]
 macro_rules! quote {
     ($($tt:tt)*) => {{

crates/swc_ecma_quote_macros/src/ast/lit.rs

@@ -5,12 +5,26 @@ use swc_ecma_ast::*;
 use syn::{ExprLit, LitBool, LitFloat};
 
 use super::ToCode;
-use crate::ctxt::Ctx;
+use crate::{builder::Builder, ctxt::Ctx};
 
 fail_todo!(BigInt);
 fail_todo!(JSXText);
 
-impl_struct!(Str, [span, value, raw]);
+impl ToCode for Str {
+    fn to_code(&self, cx: &crate::ctxt::Ctx) -> syn::Expr {
+        if let Some(var_name) = self.value.strip_prefix('$') {
+            if let Some(var) = cx.var(crate::ctxt::VarPos::Str, var_name) {
+                return var.get_expr();
+            }
+        }
+
+        let mut builder = Builder::new("Str");
+        builder.add("span", ToCode::to_code(&self.span, cx));
+        builder.add("value", ToCode::to_code(&self.value, cx));
+        builder.add("raw", ToCode::to_code(&self.raw, cx));
+        syn::Expr::Struct(builder.build())
+    }
+}
 impl_struct!(Bool, [span, value]);
 impl_struct!(Null, [span]);
 impl_struct!(Number, [span, value, raw]);

crates/swc_ecma_quote_macros/src/ctxt.rs

@@ -25,6 +25,7 @@ pub enum VarPos {
     Ident,
     Expr,
     Pat,
+    Str,
 }
 
 #[derive(Debug)]
@@ -137,6 +138,7 @@ pub(super) fn prepare_vars(
                 VarPos::Ident => "Ident",
                 VarPos::Expr => "Expr",
                 VarPos::Pat => "Pat",
+                VarPos::Str => "Str",
             },
             call_site(),
         );