feat: Ability to register variables on a builder.

uclicious_derive/src/builder.rs

@@ -156,7 +156,6 @@ impl< 'a > ToTokens for BuildMethod < 'a > {
         let vis = &self.visibility;
         let target_ty = &self.target_ty;
         let target_ty_generics = &self.target_ty_generics;
-        let doc_comment = &self.doc_comment;
         let default_struct = self.default_struct.as_ref().map(|default_expr| {
             let ident = syn::Ident::new(DEFAULT_STRUCT_NAME, Span::call_site());
             quote!(let #ident: #target_ty #target_ty_generics = #default_expr;)
@@ -167,7 +166,7 @@ impl< 'a > ToTokens for BuildMethod < 'a > {
         let ucl_obj_error_ty = bindings::ucl_object_error();
         let from_obj = bindings::from_object_trait();
         tokens.append_all(quote!(
-            #doc_comment
+            #[doc = "Build target struct or return first encountered error."]
             #vis fn #ident(mut self) -> #result<#target_ty #target_ty_generics, #boxed_error> {
                 #default_struct
                 let root = self.__parser.get_object().map_err(|e: #ucl_error_ty| e.boxed() as #boxed_error)?;
@@ -209,7 +208,7 @@ impl< 'a > ToTokens for Builder < 'a > {
                 #[allow(dead_code)]
                 impl #impl_generics #builder_ident #ty_generics #where_clause {
                     #(#functions)*
-
+                    /// Create a new builder.
                     #builder_vis fn new() -> #result_ty<Self #ty_generics #where_clause, #ucl_error_ty> {
                         #parser
                         #(#vars)*
@@ -240,6 +239,7 @@ impl<'a> ToTokens for IntoBuilder<'a> {
             .unwrap_or((None, None, None));
         tokens.append_all(quote!(
             impl #target {
+                /// Creates a builder struct that can be used to create this struct.
                 #builder_vis fn builder() -> #result_ty<#builder_ident #ty_generics #where_clause, #ucl_error_ty> {
                     #builder_ident::new()
                 }

uclicious_derive/src/parser.rs

@@ -38,12 +38,29 @@ impl ToTokens for ParserMethods {
         let err = bindings::ucl_parser_error();
         let path = bindings::path_ty();
         tokens.append_all(quote! (
+        /// Add a chunk of text to the parser. String must:
+        /// - not have `\0` character;
+        /// - must be valid UCL object;
         #vis fn add_chunk_full<C: #as_ref<str>>(&mut self, chunk: C, priority: #priority, strategy: #dup_strategy) -> #result<(), #err> {
             self.__parser.add_chunk_full(chunk, priority, strategy)
         }
+        /// Add a file by a file path to the parser. This function uses mmap call to load file, therefore, it should not be shrunk during parsing.
         #vis fn add_file_full<F: #as_ref<#path>>(&mut self, file: F, priority: #priority, strategy: #dup_strategy) -> #result<(), #err> {
             self.__parser.add_file_full(file, priority, strategy)
         }
+        /// Register new variable `$var` that should be replaced by the parser to the `value` string.
+        /// Variables need to be registered _before_ they are referenced.
+        ///
+        /// #### Panics
+        /// This function panics if either `var` or `value` has `\0`.
+        #vis fn register_variable<K: #as_ref<str>, V: #as_ref<str>>(
+            &mut self,
+            var: K,
+            value: V,
+        ) -> &mut Self {
+            self.__parser.register_variable(var, value);
+            self
+        }
         ))
     }
 }