Minor refactors to make wiggle-generate reusable externally (#34)

* wiggle-generate: pass witx doc in explicitly

* wiggle-generate: Names takes &Config, minor refactor for reuse

crates/generate/src/funcs.rs

@@ -11,22 +11,10 @@ pub fn define_func(names: &Names, func: &witx::InterfaceFunc) -> TokenStream {
     let ctx_type = names.ctx_type();
     let coretype = func.core_type();
 
-    let params = coretype.args.iter().map(|arg| match arg.signifies {
-        witx::CoreParamSignifies::Value(atom) => {
-            let atom = names.atom_type(atom);
-            let name = names.func_param(&arg.param.name);
-            quote!(#name : #atom)
-        }
-        witx::CoreParamSignifies::PointerTo => {
-            let atom = names.atom_type(witx::AtomType::I32);
-            let name = names.func_ptr_binding(&arg.param.name);
-            quote!(#name: #atom)
-        }
-        witx::CoreParamSignifies::LengthOf => {
-            let atom = names.atom_type(witx::AtomType::I32);
-            let name = names.func_len_binding(&arg.param.name);
-            quote!(#name: #atom)
-        }
+    let params = coretype.args.iter().map(|arg| {
+        let name = names.func_core_arg(arg);
+        let atom = names.atom_type(arg.repr());
+        quote!(#name : #atom)
     });
 
     let abi_args = quote!(

crates/generate/src/lib.rs

@@ -14,9 +14,7 @@ pub use module_trait::define_module_trait;
 pub use names::Names;
 pub use types::define_datatype;
 
-pub fn generate(config: Config) -> TokenStream {
-    let doc = witx::load(&config.witx.paths).expect("loading witx");
-
+pub fn generate(doc: &witx::Document, config: &Config) -> TokenStream {
     let names = Names::new(config); // TODO parse the names from the invocation of the macro, or from a file?
 
     let types = doc.typenames().map(|t| define_datatype(&names, &t));

crates/generate/src/names.rs

@@ -12,8 +12,10 @@ pub struct Names {
 }
 
 impl Names {
-    pub fn new(config: Config) -> Names {
-        Names { config }
+    pub fn new(config: &Config) -> Names {
+        Names {
+            config: config.clone(),
+        }
     }
     pub fn ctx_type(&self) -> Ident {
         self.config.ctx.name.clone()
@@ -118,6 +120,14 @@ impl Names {
         }
     }
 
+    pub fn func_core_arg(&self, arg: &witx::CoreParamType) -> Ident {
+        match arg.signifies {
+            witx::CoreParamSignifies::Value { .. } => self.func_param(&arg.param.name),
+            witx::CoreParamSignifies::PointerTo => self.func_ptr_binding(&arg.param.name),
+            witx::CoreParamSignifies::LengthOf => self.func_len_binding(&arg.param.name),
+        }
+    }
+
     /// For when you need a {name}_ptr binding for passing a value by reference:
     pub fn func_ptr_binding(&self, id: &Id) -> Ident {
         format_ident!("{}_ptr", id.as_str().to_snake_case())