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Diffstat (limited to 'mingling_macros/src/program_setup.rs')
| -rw-r--r-- | mingling_macros/src/program_setup.rs | 199 |
1 files changed, 199 insertions, 0 deletions
diff --git a/mingling_macros/src/program_setup.rs b/mingling_macros/src/program_setup.rs new file mode 100644 index 0000000..54da898 --- /dev/null +++ b/mingling_macros/src/program_setup.rs @@ -0,0 +1,199 @@ +//! Setup Attribute Macro Implementation +//! +//! This module provides the `#[setup]` attribute macro for automatically +//! generating structs that implement the `ProgramSetup` trait from functions. + +use proc_macro::TokenStream; +use quote::quote; +use syn::spanned::Spanned; +use syn::{ + FnArg, Ident, ItemFn, Pat, PatType, ReturnType, Signature, Type, TypePath, parse_macro_input, +}; + +/// Extracts the program parameter from function arguments +fn extract_program_param(sig: &Signature) -> syn::Result<(Pat, TypePath)> { + // The function should have exactly one parameter + if sig.inputs.len() != 1 { + return Err(syn::Error::new( + sig.inputs.span(), + "Setup function must have exactly one parameter", + )); + } + + let arg = &sig.inputs[0]; + match arg { + FnArg::Typed(PatType { pat, ty, .. }) => { + // Extract the pattern (parameter name) + let param_pat = (**pat).clone(); + + // Extract the type, handling references like &mut ThisProgram + match &**ty { + Type::Path(type_path) => Ok((param_pat, type_path.clone())), + Type::Reference(type_ref) => { + // Handle reference types like &mut ThisProgram + match &*type_ref.elem { + Type::Path(type_path) => Ok((param_pat, type_path.clone())), + _ => Err(syn::Error::new( + ty.span(), + "Reference parameter must point to a type path", + )), + } + } + _ => Err(syn::Error::new( + ty.span(), + "Parameter type must be a type path or reference to a type path", + )), + } + } + FnArg::Receiver(_) => Err(syn::Error::new( + arg.span(), + "Setup function cannot have self parameter", + )), + } +} + +/// Validates that the parameter type is `ThisProgram` +fn validate_any_program_param(type_path: &TypePath) -> syn::Result<()> { + // Check if the type is `ThisProgram` + let segments = &type_path.path.segments; + if segments.len() == 1 && segments[0].ident == "ThisProgram" { + Ok(()) + } else { + // Check if it's a qualified path like mingling::marker::ThisProgram + let mut is_any_program = false; + if segments.len() > 1 { + // Check if the last segment is "ThisProgram" + if segments.last().unwrap().ident == "ThisProgram" { + is_any_program = true; + } + } + + if is_any_program { + Ok(()) + } else { + Err(syn::Error::new( + type_path.span(), + "Setup function parameter must be `mingling::marker::ThisProgram`", + )) + } + } +} + +/// Extracts and validates the return type +fn extract_return_type(sig: &Signature) -> syn::Result<()> { + // Setup functions should return () or have no return type + match &sig.output { + ReturnType::Type(_, ty) => { + // Check if it's () + match &**ty { + Type::Tuple(tuple) if tuple.elems.is_empty() => Ok(()), + _ => Err(syn::Error::new( + ty.span(), + "Setup function must return () or have no return type", + )), + } + } + ReturnType::Default => Ok(()), + } +} + +pub fn setup_attr(attr: TokenStream, item: TokenStream) -> TokenStream { + // Parse the attribute arguments (e.g., MyProgram from #[setup(MyProgram)]) + // If no argument is provided, use DefaultProgram + let (program_name, use_crate_prefix) = if attr.is_empty() { + ( + Ident::new("DefaultProgram", proc_macro2::Span::call_site()), + true, + ) + } else { + (parse_macro_input!(attr as Ident), false) + }; + + // Parse the function item + let input_fn = parse_macro_input!(item as ItemFn); + + // Validate the function is not async + if input_fn.sig.asyncness.is_some() { + return syn::Error::new(input_fn.sig.span(), "Setup function cannot be async") + .to_compile_error() + .into(); + } + + // Extract the program parameter + let (program_param, program_type) = match extract_program_param(&input_fn.sig) { + Ok(info) => info, + Err(e) => return e.to_compile_error().into(), + }; + + // Validate that the parameter is ThisProgram + if let Err(e) = validate_any_program_param(&program_type) { + return e.to_compile_error().into(); + } + + // Validate return type + if let Err(e) = extract_return_type(&input_fn.sig) { + return e.to_compile_error().into(); + } + + // Get the function body + let fn_body = &input_fn.block; + + // Get function attributes (excluding the setup attribute) + let mut fn_attrs = input_fn.attrs.clone(); + + // Remove any #[setup(...)] attributes to avoid infinite recursion + fn_attrs.retain(|attr| !attr.path().is_ident("setup")); + + // Get function visibility + let vis = &input_fn.vis; + + // Get function name + let fn_name = &input_fn.sig.ident; + + // Generate struct name from function name using pascal_case + let pascal_case_name = just_fmt::pascal_case!(fn_name.to_string()); + let struct_name = Ident::new(&pascal_case_name, fn_name.span()); + + // Generate the struct and implementation + let expanded = if use_crate_prefix { + quote! { + #(#fn_attrs)* + #vis struct #struct_name; + + impl ::mingling::setup::ProgramSetup<DefaultProgram, DefaultProgram> for #struct_name { + fn setup(&mut self, program: &mut ::mingling::Program<DefaultProgram, DefaultProgram>) { + let _ = ThisProgram; + // Call the original function with the actual Program type + #fn_name(program); + } + } + + // Keep the original function for internal use + #(#fn_attrs)* + #vis fn #fn_name(#program_param: &mut ::mingling::Program<DefaultProgram, DefaultProgram>) { + #fn_body + } + } + } else { + quote! { + #(#fn_attrs)* + #vis struct #struct_name; + + impl ::mingling::setup::ProgramSetup<#program_name, #program_name> for #struct_name { + fn setup(&mut self, program: &mut ::mingling::Program<#program_name, #program_name>) { + let _ = ThisProgram; + // Call the original function with the actual Program type + #fn_name(program); + } + } + + // Keep the original function for internal use + #(#fn_attrs)* + #vis fn #fn_name(#program_param: &mut ::mingling::Program<#program_name, #program_name>) { + #fn_body + } + } + }; + + expanded.into() +} |