1 files changed, 62 insertions, 0 deletions
diff --git a/src/generate/summon_checker.rs b/src/generate/summon_checker.rs
new file mode 100644
index 0000000..743c199
--- /dev/null
+++ b/src/generate/summon_checker.rs
@@ -0,0 +1,62 @@
+use proc_macro2::TokenStream;
+use quote::quote;
+use syn::Error;
+
+use crate::info_structures::{ArgType, BuilderType, StructInfo};
+
+pub fn generate_checker_summoner(info: &StructInfo) -> Result<TokenStream, Error> {
+    let mut code: Vec<TokenStream> = Vec::new();
+    let mut params: Vec<TokenStream> = Vec::new();
+    let mut value_consumers: Vec<TokenStream> = Vec::new();
+    let mut template_consumers: Vec<TokenStream> = Vec::new();
+    for field in &info.fields {
+        let field_name = &field.name;
+
+        let arg_type = field.make_constructor_arg_type(&info, BuilderType::Sync)?;
+        if let ArgType::Plain(plain_type) = arg_type {
+            // No fancy builder function, we can just move the value directly into the struct.
+            params.push(quote! { #field_name: #plain_type });
+        } else if let ArgType::TraitBound(bound_type) = arg_type {
+            // Trait bounds are much trickier. We need a special syntax to accept them in the
+            // contructor, and generic parameters need to be added to the builder struct to make
+            // it work.
+            let builder_name = field.builder_name();
+            params.push(quote! { #builder_name : impl #bound_type });
+            let mut builder_args = Vec::new();
+            for (_, borrow) in field.borrows.iter().enumerate() {
+                let borrowed_name = &info.fields[borrow.index].name;
+                if borrow.mutable {
+                    builder_args.push(quote! { &mut #borrowed_name });
+                } else {
+                    builder_args.push(quote! { &#borrowed_name });
+                }
+            }
+            code.push(quote! { let #field_name = #builder_name (#(#builder_args),*); });
+        }
+        if field.is_mutably_borrowed() {
+            code.push(quote! { let mut #field_name = #field_name; });
+        } else {
+            code.push(quote! { let #field_name = #field_name; });
+            value_consumers.push(quote! { #field_name: &#field_name });
+        }
+    }
+    for (_ty, ident) in info.generic_consumers() {
+        template_consumers.push(quote! { #ident: ::core::marker::PhantomData });
+    }
+    let generic_params = info.generic_params();
+    let where_clause = &info.generics.where_clause;
+    let borrowed_generic_params_inferred = info.borrowed_generic_params_inferred();
+    Ok(quote! {
+        fn check_if_okay_according_to_checkers<#generic_params>(
+            #(#params,)*
+        )
+        #where_clause
+        {
+            #(#code;)*
+            BorrowedFields::#borrowed_generic_params_inferred {
+                #(#value_consumers,)*
+                #(#template_consumers,)*
+            };
+        }
+    })
+}