use join_to_string::join; use ra_syntax::{ ast::{self, AstNode, NameOwner, TypeParamsOwner}, TextUnit, }; use crate::assists::{AssistCtx, Assist}; pub fn add_impl(ctx: AssistCtx) -> Option { let nominal = ctx.node_at_offset::()?; let name = nominal.name()?; ctx.build("add impl", |edit| { let type_params = nominal.type_param_list(); let start_offset = nominal.syntax().range().end(); let mut buf = String::new(); buf.push_str("\n\nimpl"); if let Some(type_params) = type_params { type_params.syntax().text().push_to(&mut buf); } buf.push_str(" "); buf.push_str(name.text().as_str()); if let Some(type_params) = type_params { let lifetime_params = type_params .lifetime_params() .filter_map(|it| it.lifetime()) .map(|it| it.text()); let type_params = type_params .type_params() .filter_map(|it| it.name()) .map(|it| it.text()); join(lifetime_params.chain(type_params)) .surround_with("<", ">") .to_buf(&mut buf); } buf.push_str(" {\n"); edit.set_cursor(start_offset + TextUnit::of_str(&buf)); buf.push_str("\n}"); edit.insert(start_offset, buf); }) } #[cfg(test)] mod tests { use super::*; use crate::assists::check_assist; #[test] fn test_add_impl() { check_assist( add_impl, "struct Foo {<|>}\n", "struct Foo {}\n\nimpl Foo {\n<|>\n}\n", ); check_assist( add_impl, "struct Foo {<|>}", "struct Foo {}\n\nimpl Foo {\n<|>\n}", ); check_assist( add_impl, "struct Foo<'a, T: Foo<'a>> {<|>}", "struct Foo<'a, T: Foo<'a>> {}\n\nimpl<'a, T: Foo<'a>> Foo<'a, T> {\n<|>\n}", ); } }