Add codegen for recursive statics case

We also flip the recursive_statics fields to recursive_nonstatics; This makes the codegen a little easier.  It also has a hacky way to hard code in some recursive statics for testing

crates/aiken-lang/src/gen_uplc.rs

@@ -2690,6 +2690,19 @@ impl<'a> CodeGenerator<'a> {
             // first grab dependencies
             let func_params = params;
 
+            // HACK: partition params into the "static recursives" and otherwise
+            // for now, we just do this based on the name, but it should be detected
+            // as an optimization pass
+            let recursive_static_indexes: Vec<usize> = func_params.iter().enumerate().filter(|(idx, p)| {
+                p.starts_with("pi_recursive_hack_")
+            }).map(|(idx, _)| idx).collect();
+            let recursive_nonstatics: Vec<String> = func_params.iter().cloned().filter(|p| {
+                !p.starts_with("pi_recursive_hack_")
+            }).collect();
+
+            println!("~~ recursive_nonstatics: {:?}", recursive_nonstatics);
+            println!("~~ func_params: {:?}", func_params);
+
             let params_empty = func_params.is_empty();
 
             let deps = (tree_path, func_deps.clone());
@@ -2697,7 +2710,7 @@ impl<'a> CodeGenerator<'a> {
             if !params_empty {
                 if is_recursive {
                     body.traverse_tree_with(&mut |air_tree: &mut AirTree, _| {
-                        modify_self_calls(air_tree, key, variant);
+                        modify_self_calls(air_tree, key, variant, &recursive_static_indexes);
                     });
                 }
 
@@ -2707,7 +2720,7 @@ impl<'a> CodeGenerator<'a> {
                     variant,
                     func_params.clone(),
                     is_recursive,
-                    vec![],
+                    recursive_nonstatics,
                     body,
                 );
 
@@ -2832,7 +2845,7 @@ impl<'a> CodeGenerator<'a> {
 
                 if is_dependent_recursive {
                     dep_air_tree.traverse_tree_with(&mut |air_tree: &mut AirTree, _| {
-                        modify_self_calls(air_tree, &dep_key, &dep_variant);
+                        modify_self_calls(air_tree, &dep_key, &dep_variant, &vec![]);
                     });
                 }
 
@@ -2840,9 +2853,9 @@ impl<'a> CodeGenerator<'a> {
                     &dep_key.function_name,
                     &dep_key.module_name,
                     &dep_variant,
-                    dependent_params,
+                    dependent_params.clone(),
                     is_dependent_recursive,
-                    vec![],
+                    dependent_params,
                     dep_air_tree,
                 ));
 
@@ -3706,7 +3719,7 @@ impl<'a> CodeGenerator<'a> {
                 func_name,
                 params,
                 recursive,
-                recursive_static_params,
+                recursive_nonstatic_params,
                 module_name,
                 variant_name,
             } => {
@@ -3719,7 +3732,11 @@ impl<'a> CodeGenerator<'a> {
 
                 let mut term = arg_stack.pop().unwrap();
 
-                for param in params.iter().rev() {
+                // Introduce a parameter for each parameter
+                // NOTE: we use recursive_nonstatic_params here because
+                // if this is recursive, those are the ones that need to be passed
+                // each time
+                for param in recursive_nonstatic_params.iter().rev() {
                     func_body = func_body.lambda(param.clone());
                 }
 
@@ -3730,13 +3747,31 @@ impl<'a> CodeGenerator<'a> {
                 } else {
                     func_body = func_body.lambda(func_name.clone());
 
+                    if recursive_nonstatic_params == params {
+                        // If we don't have any recursive-static params, we can just emit the function as is
                         term = term
                             .lambda(func_name.clone())
                             .apply(Term::var(func_name.clone()).apply(Term::var(func_name.clone())))
                             .lambda(func_name)
                             .apply(func_body);
+                    } else {
+                        // If we have parameters that remain static in each recursive call,
+                        // we can construct an *outer* function to take those in
+                        // and simplify the recursive part to only accept the non-static arguments
+                        let mut outer_func_body = Term::var(&func_name).apply(Term::var(&func_name));
+                        for param in recursive_nonstatic_params.iter() {
+                            outer_func_body = outer_func_body.apply(Term::var(param));
+                        }
 
-                    // TODO: use recursive_static_params here
+                        outer_func_body = outer_func_body.lambda(&func_name).apply(func_body);
+
+                        // Now, add *all* parameters, so that other call sites don't know the difference
+                        for param in params.iter().rev() {
+                            outer_func_body = outer_func_body.lambda(param);
+                        }
+
+                        term = term.lambda(&func_name).apply(outer_func_body);
+                    }
 
                     arg_stack.push(term);
                 }

crates/aiken-lang/src/gen_uplc/air.rs

@@ -47,7 +47,7 @@ pub enum Air {
         module_name: String,
         params: Vec<String>,
         recursive: bool,
-        recursive_static_params: Vec<String>,
+        recursive_nonstatic_params: Vec<String>,
         variant_name: String,
     },
     Fn {

crates/aiken-lang/src/gen_uplc/builder.rs

@@ -583,7 +583,7 @@ pub fn erase_opaque_type_operations(
     }
 }
 
-pub fn modify_self_calls(air_tree: &mut AirTree, func_key: &FunctionAccessKey, variant: &String) {
+pub fn modify_self_calls(air_tree: &mut AirTree, func_key: &FunctionAccessKey, variant: &String, static_recursive_params: &Vec<usize>) {
     if let AirTree::Expression(AirExpression::Call { func, args, .. }) = air_tree {
         if let AirTree::Expression(AirExpression::Var {
             constructor:
@@ -599,6 +599,11 @@ pub fn modify_self_calls(air_tree: &mut AirTree, func_key: &FunctionAccessKey, v
                 && module == &func_key.module_name
                 && variant == variant_name
             {
+                // Remove any static-recursive-parameters, because they'll be bound statically
+                // above the recursive part of the function
+                for arg in static_recursive_params.iter().rev() {
+                    args.remove(*arg);
+                }
                 let mut new_args = vec![func.as_ref().clone()];
                 new_args.append(args);
                 *args = new_args;

crates/aiken-lang/src/gen_uplc/tree.rs

@@ -129,7 +129,7 @@ pub enum AirStatement {
         module_name: String,
         params: Vec<String>,
         recursive: bool,
-        recursive_static_params: Vec<String>,
+        recursive_nonstatic_params: Vec<String>,
         variant_name: String,
         func_body: Box<AirTree>,
     },
@@ -424,7 +424,7 @@ impl AirTree {
         variant_name: impl ToString,
         params: Vec<String>,
         recursive: bool,
-        recursive_static_params: Vec<String>,
+        recursive_nonstatic_params: Vec<String>,
         func_body: AirTree,
     ) -> AirTree {
         AirTree::Statement {
@@ -433,7 +433,7 @@ impl AirTree {
                 module_name: module_name.to_string(),
                 params,
                 recursive,
-                recursive_static_params,
+                recursive_nonstatic_params,
                 variant_name: variant_name.to_string(),
                 func_body: func_body.into(),
             },
@@ -878,7 +878,7 @@ impl AirTree {
                         module_name,
                         params,
                         recursive,
-                        recursive_static_params,
+                        recursive_nonstatic_params,
                         variant_name,
                         func_body,
                     } => {
@@ -887,7 +887,7 @@ impl AirTree {
                             module_name: module_name.clone(),
                             params: params.clone(),
                             recursive: *recursive,
-                            recursive_static_params: recursive_static_params.clone(),
+                            recursive_nonstatic_params: recursive_nonstatic_params.clone(),
                             variant_name: variant_name.clone(),
                         });
                         func_body.create_air_vec(air_vec);