Better step macro

Cargo.toml

@@ -29,7 +29,7 @@ step-trace = ["descriptive-gate"]
 # The following two features are mutually exclusive. Descriptive should be enabled by deafult as the vast majority
 # of unit tests use it. Compact uses memory-efficient gates and is suitable for production.
 descriptive-gate = []
-compact-gate = []
+compact-gate = ["ipa-macros/compact-gate"]
 
 [dependencies]
 ipa-macros = { version = "*", path = "./ipa-macros" }
@@ -71,14 +71,11 @@ serde = { version = "1.0", optional = true, features = ["derive"] }
 serde_json = { version = "1.0", optional = true }
 sha2 = "0.10.6"
 shuttle-crate = { package = "shuttle", version = "0.6.1", optional = true }
-strum = {version = "0.25", features = ["derive"] }
 thiserror = "1.0"
 time = { version = "0.3", optional = true }
-tinyvec = "1.6"
 tokio = { version = "1.28", features = ["rt", "rt-multi-thread", "macros"] }
 tokio-rustls = { version = "0.24.0", optional = true }
 tokio-stream = "0.1.14"
-tokio-util = "0.7.8"
 toml = { version = "0.7", optional = true }
 tower = { version = "0.4.13", optional = true }
 tower-http = { version = "0.4.0", optional = true, features = ["trace"] }

ipa-macros/Cargo.toml

@@ -4,20 +4,12 @@ version = "0.1.0"
 rust-version = "1.64.0"
 edition = "2021"
 
-[lib]
-proc-macro = true
-
 [features]
-trybuild = []
+compact-gate = []
 
-[[test]]
-name = "tests"
-path = "tests/mod.rs"
-required-features = ["trybuild"]
+[lib]
+proc-macro = true
 
 [dependencies]
-syn = { version = "2.0.15", features = ["full"] }
+syn = { version = "2.0.15", features = ["full", "extra-traits"] }
 quote = "1.0.27"
-
-[dev-dependencies]
-trybuild = { version = "1.0.80", features = ["diff"] }

ipa-macros/src/derive_gate/mod.rs

@@ -1,62 +1,10 @@
-use crate::parser::{group_by_modules, ipa_state_transition_map, module_string_to_ast};
+use crate::parser::{group_by_modules, ipa_state_transition_map};
 use proc_macro::TokenStream;
 use quote::quote;
 use syn::{parse_macro_input, DeriveInput};
 
-// Procedural macro to derive the Step and StepNarrow traits and generate a memory-efficient gate.
-//
-// The goal is to generate a state transition graph and the corresponding `StepNarrow` implementations
-// for the IPA protocol. This macro assumes that a complete IPA steps file exists in the repo at the
-// location specified as `STEPS_FILE`. The steps file can be generated by running `collect_steps.py`.
-//
-// The steps file contains a list of narrowed steps, where each line represents a hierarchy of narrowed
-// steps delimited by "/". For example, the following lines represent a hierarchy of narrowed steps:
-//
-//     RootStep                                => 0
-//     RootStep/StepA::A1                      => 1
-//     RootStep/StepA::A1/StepB::B1            => 2
-//     RootStep/StepA::A1/StepB::B2            => 3
-//     RootStep/StepC::C1                      => 4
-//     RootStep/StepC::C1/StepD::D1            => 5
-//     RootStep/StepC::C1/StepD::D1/StepA::A2  => 6
-//     RootStep/StepC::C2                      => 7
-//
-// From these lines, we want to generate StepNarrow implementations for each step.
-//
-//     impl StepNarrow<StepA> for Compact {
-//         fn narrow(&self, step: &StepA) -> Self {
-//             Self(match (self.0, step.as_ref()) {
-//                 (0, "A1") => 1,
-//                 (5, "A2") => 6,
-//                 _ => panic!("invalid state transition"),
-//             })
-//         }
-//     }
-//     impl StepNarrow<StepB> for Compact {
-//         fn narrow(&self, step: &StepB) -> Self {
-//             Self(match (self.0, step.as_ref()) {
-//                 (1, "B1") => 2,
-//                 (1, "B2") => 3,
-//                 _ => panic!("invalid state transition"),
-//             })
-//         }
-//     }
-//     ...
-//
-//
-// Currently, this derive notation assumes it annotates the `Compact` struct defined in
-// `src/protocol/step/compact.rs`. The `Compact` struct is a wrapper around a `u16` value that
-// represents the current state of the IPA protocol.
-//
-// In the future, we might change the macro to annotate each step in the IPA protocol. The macro
-// will then generate both `Descriptive` and `Compact` implementations for the step. However, that
-// kind of derive macro requires more annotations such as the fully qualified module path of the
-// step. This is because there are many locally-defined `Step` enums in IPA, and we need to
-// disambiguate them. However, proc macro doesn't receive the fully qualified module path of the
-// annotated struct.
-
-/// Generate a state transition graph and the corresponding `StepNarrow` implementations for the
-/// IPA protocol.
+/// Generate a state transition graph and the corresponding `AsRef<str>`
+/// and `deserialize()` implementations for `Compact` gate.
 pub fn expand(item: TokenStream) -> TokenStream {
     // `item` is the `struct Compact(u16)` in AST
     let ast = parse_macro_input!(item as DeriveInput);
@@ -66,39 +14,16 @@ pub fn expand(item: TokenStream) -> TokenStream {
         _ => panic!("derive Gate expects a struct"),
     }
 
-    // we omit the fully qualified module path here because we want to be able to test the macro
-    // using our own implementations of `Step` and `StepNarrow`.
     let mut expanded = quote!(
-        impl Step for #gate {}
+        impl crate::protocol::step::Step for #gate {}
     );
 
     let steps = ipa_state_transition_map();
     let grouped_steps = group_by_modules(&steps);
     let mut reverse_map = Vec::new();
     let mut deserialize_map = Vec::new();
 
-    for (module, steps) in grouped_steps {
-        // generate the `StepNarrow` implementation for each module
-        let module = module_string_to_ast(&module);
-        let states = steps.iter().map(|s| {
-            let new_state = &s.name;
-            let new_state_id = s.id;
-            let previous_state_id = s.get_parent().unwrap().id;
-            quote!(
-                (#previous_state_id, #new_state) => #new_state_id,
-            )
-        });
-        expanded.extend(quote!(
-            impl StepNarrow<#module> for #gate {
-                fn narrow(&self, step: &#module) -> Self {
-                    Self(match (self.0, step.as_ref()) {
-                        #(#states)*
-                        _ => static_state_map(self.0, step.as_ref()),
-                    })
-                }
-            }
-        ));
-
+    for (_, steps) in grouped_steps {
         // generate the reverse map for `impl AsRef<str> for Compact`
         // this is used to convert a state ID to a string representation of the state.
         reverse_map.extend(steps.iter().map(|s| {