Add suffix macro to bisync

bisync/Cargo.toml

@@ -9,4 +9,4 @@ repository = "https://github.com/JM4ier/bisync"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-bisync_macros = "0.2.3"
+bisync_macros = { path = "../bisync_macros" }

bisync/src/lib.rs

@@ -9,6 +9,8 @@
 //! #[path = "."]
 //! pub mod asynchronous {
 //!     use bisync::asynchronous::*;
+//!     // If you use the `suffix!` macro, it needs to be in scope:
+//!     // use bisync::suffix;
 //!     mod inner;
 //!     pub use inner::*;
 //! }
@@ -17,6 +19,8 @@
 //! #[path = "."]
 //! pub mod blocking {
 //!     use bisync::synchronous::*;
+//!     // If you use the `suffix!` macro, it needs to be in scope:
+//!     // use bisync::suffix;
 //!     mod inner;
 //!     pub use inner::*;
 //! }
@@ -28,7 +32,7 @@
 //! // inner.rs
 //!
 //! // these are all the available definitions:
-//! use super::{bisync, only_sync, only_async, SYNC, ASYNC};
+//! use super::{bisync, only_sync, only_async, SYNC, ASYNC, suffix};
 //!  
 //! #[bisync]
 //! pub async fn foo() -> String {
@@ -46,8 +50,23 @@
 //!     }
 //!  
 //!     baz().await
+//!
+//!     // Example usage of the suffix macro assuming http_get is the base method
+//!     // and your crate has "async" and "blocking" features.
+//!     // The suffix macro uses these features for conditional compilation.
+//!     let _response = suffix!("_async", http_get("https://example.com").await.unwrap());
+//!     // This would expand to:
+//!     // #[cfg(feature = "async")] { http_get_async("https://example.com").await.unwrap() }
+//!     // #[cfg(all(feature = "blocking", not(feature = "async")))] { http_get("https://example.com").await.unwrap() }
+//!     // Then #[bisync]'s internal_strip_async would remove .await for the blocking path.
 //! }
-//!  
+//!
+//!
+//!
+//! // Dummy function for example
+//! async fn http_get(_url: &str) -> Result<String, ()> { Ok("dummy sync".to_string()) }
+//! async fn http_get_async(_url: &str) -> Result<String, ()> { Ok("dummy async".to_string()) }
+//!
 //! #[only_sync]
 //! fn baz() -> String {
 //!     ureq::get("https://example.com")
@@ -72,6 +91,20 @@
 //! As you can see, we prevent duplicate definitions of `foo` and `bar` because they get generated twice,
 //! once in synchronous form, and once in asynchronous form.
 //!
+//! The `suffix!` macro allows conditional compilation of method calls based on features of the *crate using bisync*,
+//! typically "async" and "blocking". It suffixes the method call immediately preceding an `.await`.
+//!
+//! **Using `suffix!` Macro:**
+//!
+//! The `suffix!` macro expects the *user's crate* to have features like "async" and "blocking" defined.
+//! It's called like this: `suffix!("_async", expression_containing_method().await)`.
+//!
+//! - If `feature = "async"` is enabled: `expression_containing_method_async().await`
+//! - If `feature = "blocking"` (and not "async") is enabled: `expression_containing_method().await`
+//!
+//! The `#[bisync]` attribute will then further process this: `internal_strip_async` will remove the `.await`
+//! from the blocking path.
+
 #![no_std]
 
 /// The definitions to use for the synchronous code variation
@@ -102,3 +135,5 @@ pub mod asynchronous {
     pub const ASYNC: bool = true;
 }
 
+// Re-export the `suffix` procedural macro so users can call `bisync::suffix!`
+pub use ::bisync_macros::suffix;

bisync_macros/Cargo.toml

@@ -10,3 +10,6 @@ repository = "https://github.com/JM4ier/bisync"
 proc-macro = true
 
 [dependencies]
+syn = { version = "2.0", features = ["full", "visit-mut"] }
+quote = "1.0"
+proc-macro2 = "1.0"

bisync_macros/src/lib.rs

@@ -1,6 +1,17 @@
 //! Do not use this crate directly.
 
-use proc_macro::{Group, TokenStream};
+use proc_macro::{Group, TokenStream, TokenTree};
+
+use quote::quote;
+use syn::{
+    parse::{Parse, ParseStream},
+    parse_macro_input,
+    visit_mut::{self, VisitMut},
+    Expr, ExprAwait, Ident, LitStr, Token,
+};
+
+// Original bisync attribute macros
+// ================================
 
 #[proc_macro_attribute]
 pub fn internal_noop(_attr: TokenStream, item: TokenStream) -> TokenStream {
@@ -14,8 +25,6 @@ pub fn internal_delete(_attr: TokenStream, _item: TokenStream) -> TokenStream {
 
 #[proc_macro_attribute]
 pub fn internal_strip_async(attr: TokenStream, item: TokenStream) -> TokenStream {
-    use proc_macro::TokenTree;
-
     let mut new = Vec::new();
     let tokens: Vec<TokenTree> = item.into_iter().collect();
     let mut i = 0;
@@ -48,10 +57,79 @@ pub fn internal_strip_async(attr: TokenStream, item: TokenStream) -> TokenStream
                     new.push(tokens[i].clone());
                 }
             }
-            TokenTree::Literal(..) => new.push(tokens[i].clone()),
+            TokenTree::Literal(..) => {
+                new.push(tokens[i].clone());
+            }
         }
         i += 1;
     }
-
     new.into_iter().collect()
 }
+
+// Function-like Proc-Macro: suffix
+// ====================================
+
+struct SuffixMacroInput {
+    suffix_str: LitStr,
+    _comma: Token![,],
+    expr: Expr,
+}
+
+impl Parse for SuffixMacroInput {
+    fn parse(input: ParseStream) -> syn::Result<Self> {
+        Ok(SuffixMacroInput {
+            suffix_str: input.parse()?,
+            _comma: input.parse()?,
+            expr: input.parse()?,
+        })
+    }
+}
+
+struct AwaitMethodSuffixer<'a> {
+    suffix: &'a str,
+}
+
+impl<'a> VisitMut for AwaitMethodSuffixer<'a> {
+    fn visit_expr_await_mut(&mut self, expr_await: &mut ExprAwait) {
+        if let Expr::MethodCall(method_call) = &mut *expr_await.base {
+            let original_method_ident = method_call.method.clone();
+            let new_method_name_str =
+                format!("{}{}", original_method_ident.to_string(), self.suffix);
+            method_call.method = Ident::new(&new_method_name_str, original_method_ident.span());
+        }
+        visit_mut::visit_expr_await_mut(self, expr_await);
+    }
+
+    fn visit_expr_mut(&mut self, expr: &mut Expr) {
+        visit_mut::visit_expr_mut(self, expr);
+    }
+}
+
+#[proc_macro]
+pub fn suffix(input: TokenStream) -> TokenStream {
+    let parsed_input = parse_macro_input!(input as SuffixMacroInput);
+    let suffix_value = parsed_input.suffix_str.value();
+
+    let mut async_expr_transformed = parsed_input.expr.clone();
+    let blocking_expr_original = parsed_input.expr;
+
+    let mut suffixer = AwaitMethodSuffixer {
+        suffix: &suffix_value,
+    };
+    suffixer.visit_expr_mut(&mut async_expr_transformed);
+
+    let output = quote! {
+        {
+            #[cfg(feature = "async")]
+            {
+                #async_expr_transformed
+            }
+            #[cfg(all(feature = "blocking", not(feature = "async")))]
+            {
+                #blocking_expr_original
+            }
+        }
+    };
+
+    output.into()
+}