feat: add support for setter prefix and suffix

CHANGELOG.md

@@ -10,6 +10,11 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
   generated code itself does trigger the deprecation warning, and instead the
   setter for that field now does.
 
+### Added
+- Support for setter method prefixes and suffixes `#[builder(field_defaults(setter(prefix = "...", suffix = "...")))]`.
+  This either prepends or appends the provided string to the setter method. This allows method names like: `set_x()`,
+  `with_y()`, or `set_z_value()`.
+
 ## 0.14.0 - 2023-03-08
 ### Added
 - `build_method(into)` and `build_method(into = ...)`.

examples/complicate_build.rs

@@ -1,7 +1,7 @@
 mod scope {
     use typed_builder::TypedBuilder;
 
-    #[derive(PartialEq, TypedBuilder)]
+    #[derive(Debug, PartialEq, TypedBuilder)]
     #[builder(build_method(vis="", name=__build))]
     pub struct Foo {
         // Mandatory Field:
@@ -36,7 +36,7 @@ mod scope {
         }
     }
 
-    #[derive(PartialEq)]
+    #[derive(Debug, PartialEq)]
     pub struct Bar {
         pub x: i32,
         pub y: Option<i32>,
@@ -47,7 +47,7 @@ mod scope {
 use scope::{Bar, Foo};
 
 fn main() {
-    assert!(Foo::builder().x(1).y(2).z(3).build() == Bar { x: 2, y: Some(3), z: 4 });
+    assert_eq!(Foo::builder().x(1).y(2).z(3).build(), Bar { x: 2, y: Some(3), z: 4 });
 
     // This will not compile - because `__build` is a private method
     // Foo::builder().x(1).y(2).z(3).__build()

examples/example.rs

@@ -1,6 +1,6 @@
 use typed_builder::TypedBuilder;
 
-#[derive(PartialEq, TypedBuilder)]
+#[derive(Debug, PartialEq, TypedBuilder)]
 struct Foo {
     // Mandatory Field:
     x: i32,
@@ -16,13 +16,13 @@ struct Foo {
 }
 
 fn main() {
-    assert!(Foo::builder().x(1).y(2).z(3).build() == Foo { x: 1, y: Some(2), z: 3 });
+    assert_eq!(Foo::builder().x(1).y(2).z(3).build(), Foo { x: 1, y: Some(2), z: 3 });
 
     // Change the order of construction:
-    assert!(Foo::builder().z(1).x(2).y(3).build() == Foo { x: 2, y: Some(3), z: 1 });
+    assert_eq!(Foo::builder().z(1).x(2).y(3).build(), Foo { x: 2, y: Some(3), z: 1 });
 
     // Optional fields are optional:
-    assert!(Foo::builder().x(1).build() == Foo { x: 1, y: None, z: 20 });
+    assert_eq!(Foo::builder().x(1).build(), Foo { x: 1, y: None, z: 20 });
 
     // This will not compile - because we did not set x:
     // Foo::builder().build();

examples/example_prefix_suffix.rs

@@ -0,0 +1,39 @@
+use typed_builder::TypedBuilder;
+
+#[derive(Debug, PartialEq, TypedBuilder)]
+#[builder(field_defaults(setter(prefix = "with_", suffix = "_value")))]
+struct Foo {
+    // Mandatory Field:
+    x: i32,
+
+    // #[builder(default)] without parameter - use the type's default
+    // #[builder(setter(strip_option))] - wrap the setter argument with `Some(...)`
+    #[builder(default, setter(strip_option))]
+    y: Option<i32>,
+
+    // Or you can set the default
+    #[builder(default = 20)]
+    z: i32,
+}
+
+fn main() {
+    assert_eq!(
+        Foo::builder().with_x_value(1).with_y_value(2).with_z_value(3).build(),
+        Foo { x: 1, y: Some(2), z: 3 }
+    );
+
+    // Change the order of construction:
+    assert_eq!(
+        Foo::builder().with_z_value(1).with_x_value(2).with_y_value(3).build(),
+        Foo { x: 2, y: Some(3), z: 1 }
+    );
+
+    // Optional fields are optional:
+    assert_eq!(Foo::builder().with_x_value(1).build(), Foo { x: 1, y: None, z: 20 });
+
+    // This will not compile - because we did not set x:
+    // Foo::builder().build();
+
+    // This will not compile - because we set y twice:
+    // Foo::builder().with_x_value(1).with_y_value(2).with_y_value(3);
+}

src/lib.rs

@@ -48,7 +48,7 @@
 /// // Foo::builder().x(1).y(2).y(3);
 /// ```
 ///
-/// # Customisation with attributes
+/// # Customization with attributes
 ///
 /// In addition to putting `#[derive(TypedBuilder)]` on a type, you can specify a `#[builder(…)]`
 /// attribute on the type, and on any fields in it.
@@ -148,6 +148,14 @@
 ///     `param1: Type1, param2: Type2 ...` instead of the field type itself. The parameters are
 ///     transformed into the field type using the expression `expr`. The transformation is performed
 ///     when the setter is called.
+///
+///   - `prefix = "..."` prepends the setter method with the specified prefix. For example, setting
+///     `prefix = "with_"` results in setters like `with_x` or `with_y`. This option is combinable
+///     with `suffix = "..."`.
+///
+///   - `suffix = "..."` appends the setter method with the specified suffix. For example, setting
+///     `suffix = "_value"` results in setters like `x_value` or `y_value`. This option is combinable
+///     with `prefix = "..."`.
 pub use typed_builder_macro::TypedBuilder;
 
 #[doc(hidden)]

tests/tests.rs

@@ -542,6 +542,32 @@ fn test_builder_on_struct_with_keywords() {
     );
 }
 
+#[test]
+fn test_builder_on_struct_with_keywords_prefix_suffix() {
+    #[allow(non_camel_case_types)]
+    #[derive(PartialEq, TypedBuilder)]
+    #[builder(field_defaults(setter(prefix = "set_", suffix = "_value")))]
+    struct r#struct {
+        r#fn: u32,
+        #[builder(default, setter(strip_option))]
+        r#type: Option<u32>,
+        #[builder(default = Some(()), setter(skip))]
+        r#enum: Option<()>,
+        #[builder(setter(into))]
+        r#union: String,
+    }
+
+    assert!(
+        r#struct::builder().r#set_fn_value(1).r#set_union_value("two").build()
+            == r#struct {
+                r#fn: 1,
+                r#type: None,
+                r#enum: Some(()),
+                r#union: "two".to_owned(),
+            }
+    );
+}
+
 #[test]
 fn test_field_setter_transform() {
     #[derive(PartialEq)]
@@ -671,3 +697,42 @@ fn test_into_set_generic_impl_into() {
     let bar: Bar = Foo::builder().value(42).build();
     assert_eq!(bar, Bar { value: 42 });
 }
+
+#[test]
+fn test_prefix() {
+    #[derive(Debug, PartialEq, TypedBuilder)]
+    #[builder(field_defaults(setter(prefix = "with_")))]
+    struct Foo {
+        x: i32,
+        y: i32,
+    }
+
+    let foo = Foo::builder().with_x(1).with_y(2).build();
+    assert_eq!(foo, Foo { x: 1, y: 2 })
+}
+
+#[test]
+fn test_suffix() {
+    #[derive(Debug, PartialEq, TypedBuilder)]
+    #[builder(field_defaults(setter(suffix = "_value")))]
+    struct Foo {
+        x: i32,
+        y: i32,
+    }
+
+    let foo = Foo::builder().x_value(1).y_value(2).build();
+    assert_eq!(foo, Foo { x: 1, y: 2 })
+}
+
+#[test]
+fn test_prefix_and_suffix() {
+    #[derive(Debug, PartialEq, TypedBuilder)]
+    #[builder(field_defaults(setter(prefix = "with_", suffix = "_value")))]
+    struct Foo {
+        x: i32,
+        y: i32,
+    }
+
+    let foo = Foo::builder().with_x_value(1).with_y_value(2).build();
+    assert_eq!(foo, Foo { x: 1, y: 2 })
+}

typed-builder-macro/src/field_info.rs

@@ -1,8 +1,10 @@
-use proc_macro2::{Span, TokenStream};
+use proc_macro2::{Ident, Span, TokenStream};
 use quote::{quote, ToTokens};
 use syn::{parse::Error, spanned::Spanned};
 
-use crate::util::{apply_subsections, expr_to_single_string, ident_to_type, path_to_single_string, strip_raw_ident_prefix};
+use crate::util::{
+    apply_subsections, expr_to_lit_string, expr_to_single_string, ident_to_type, path_to_single_string, strip_raw_ident_prefix,
+};
 
 #[derive(Debug)]
 pub struct FieldInfo<'a> {
@@ -73,6 +75,20 @@ impl<'a> FieldInfo<'a> {
         }
     }
 
+    pub fn setter_method_name(&self) -> Ident {
+        let name = strip_raw_ident_prefix(self.name.to_string());
+
+        if let (Some(prefix), Some(suffix)) = (&self.builder_attr.setter.prefix, &self.builder_attr.setter.suffix) {
+            Ident::new(&format!("{}{}{}", prefix, name, suffix), Span::call_site())
+        } else if let Some(prefix) = &self.builder_attr.setter.prefix {
+            Ident::new(&format!("{}{}", prefix, name), Span::call_site())
+        } else if let Some(suffix) = &self.builder_attr.setter.suffix {
+            Ident::new(&format!("{}{}", name, suffix), Span::call_site())
+        } else {
+            self.name.clone()
+        }
+    }
+
     fn post_process(mut self) -> Result<Self, Error> {
         if let Some(ref strip_bool_span) = self.builder_attr.setter.strip_bool {
             if let Some(default_span) = self.builder_attr.default.as_ref().map(Spanned::span) {
@@ -110,6 +126,8 @@ pub struct SetterSettings {
     pub strip_option: Option<Span>,
     pub strip_bool: Option<Span>,
     pub transform: Option<Transform>,
+    pub prefix: Option<String>,
+    pub suffix: Option<String>,
 }
 
 impl<'a> FieldBuilderAttr<'a> {
@@ -286,6 +304,14 @@ impl SetterSettings {
                         self.transform = Some(parse_transform_closure(assign.left.span(), *assign.right)?);
                         Ok(())
                     }
+                    "prefix" => {
+                        self.prefix = Some(expr_to_lit_string(&*assign.right)?);
+                        Ok(())
+                    }
+                    "suffix" => {
+                        self.suffix = Some(expr_to_lit_string(&*assign.right)?);
+                        Ok(())
+                    }
                     _ => Err(Error::new_spanned(&assign, format!("Unknown parameter {:?}", name))),
                 }
             }

typed-builder-macro/src/struct_info.rs

@@ -179,7 +179,7 @@ impl<'a> StructInfo<'a> {
         let reconstructing = self.included_fields().map(|f| f.name);
 
         let &FieldInfo {
-            name: ref field_name,
+            name: field_name,
             ty: field_type,
             ..
         } = field;
@@ -262,12 +262,14 @@ impl<'a> StructInfo<'a> {
         );
         let repeated_fields_error_message = format!("Repeated field {}", field_name);
 
+        let method_name = field.setter_method_name();
+
         Ok(quote! {
             #[allow(dead_code, non_camel_case_types, missing_docs)]
             impl #impl_generics #builder_name < #( #ty_generics ),* > #where_clause {
                 #deprecated
                 #doc
-                pub fn #field_name (self, #param_list) -> #builder_name <#( #target_generics ),*> {
+                pub fn #method_name (self, #param_list) -> #builder_name <#( #target_generics ),*> {
                     let #field_name = (#arg_expr,);
                     let ( #(#descructuring,)* ) = self.fields;
                     #builder_name {
@@ -285,7 +287,7 @@ impl<'a> StructInfo<'a> {
                 #[deprecated(
                     note = #repeated_fields_error_message
                 )]
-                pub fn #field_name (self, _: #repeated_fields_error_type_name) -> #builder_name <#( #target_generics ),*> {
+                pub fn #method_name (self, _: #repeated_fields_error_type_name) -> #builder_name <#( #target_generics ),*> {
                     self
                 }
             }

typed-builder-macro/src/util.rs

@@ -1,5 +1,5 @@
 use quote::ToTokens;
-use syn::parse::Parser;
+use syn::{parse::Parser, Error};
 
 pub fn path_to_single_string(path: &syn::Path) -> Option<String> {
     if path.leading_colon.is_some() {
@@ -115,3 +115,13 @@ pub fn apply_subsections(
 
     Ok(())
 }
+
+pub fn expr_to_lit_string(expr: &syn::Expr) -> Result<String, Error> {
+    match expr {
+        syn::Expr::Lit(lit) => match &lit.lit {
+            syn::Lit::Str(str) => Ok(str.value()),
+            _ => return Err(Error::new_spanned(expr, "attribute only allows str values")),
+        },
+        _ => return Err(Error::new_spanned(expr, "attribute only allows str values")),
+    }
+}