diff options
| -rw-r--r-- | crates/ide-assists/src/handlers/convert_nested_function_to_closure.rs | 209 | ||||
| -rw-r--r-- | crates/ide-assists/src/lib.rs | 4 | ||||
| -rw-r--r-- | crates/ide-assists/src/tests/generated.rs | 25 |
3 files changed, 237 insertions, 1 deletions
diff --git a/crates/ide-assists/src/handlers/convert_nested_function_to_closure.rs b/crates/ide-assists/src/handlers/convert_nested_function_to_closure.rs new file mode 100644 index 00000000000..399f87c8f50 --- /dev/null +++ b/crates/ide-assists/src/handlers/convert_nested_function_to_closure.rs @@ -0,0 +1,209 @@ +use ide_db::assists::{AssistId, AssistKind}; +use syntax::ast::{self, HasGenericParams, HasName}; +use syntax::{AstNode, SyntaxKind}; + +use crate::assist_context::{AssistContext, Assists}; + +// Assist: convert_nested_function_to_closure +// +// Converts a function that is defined within the body of another function into a closure. +// +// ``` +// fn main() { +// fn fo$0o(label: &str, number: u64) { +// println!("{}: {}", label, number); +// } +// +// foo("Bar", 100); +// } +// ``` +// -> +// ``` +// fn main() { +// let foo = |label: &str, number: u64| { +// println!("{}: {}", label, number); +// }; +// +// foo("Bar", 100); +// } +// ``` +pub(crate) fn convert_nested_function_to_closure( + acc: &mut Assists, + ctx: &AssistContext<'_>, +) -> Option<()> { + let name = ctx.find_node_at_offset::<ast::Name>()?; + let function = name.syntax().parent().and_then(ast::Fn::cast)?; + + if !is_nested_function(&function) || is_generic(&function) || has_modifiers(&function) { + return None; + } + + let target = function.syntax().text_range(); + let body = function.body()?; + let name = function.name()?; + let param_list = function.param_list()?; + + acc.add( + AssistId("convert_nested_function_to_closure", AssistKind::RefactorRewrite), + "Convert nested function to closure", + target, + |edit| { + let params = ¶m_list.syntax().text().to_string(); + let params = params.strip_prefix("(").unwrap_or(params); + let params = params.strip_suffix(")").unwrap_or(params); + + let mut body = body.to_string(); + if !has_semicolon(&function) { + body.push(';'); + } + edit.replace(target, format!("let {name} = |{params}| {body}")); + }, + ) +} + +/// Returns whether the given function is nested within the body of another function. +fn is_nested_function(function: &ast::Fn) -> bool { + function.syntax().ancestors().skip(1).find_map(ast::Item::cast).map_or(false, |it| { + matches!(it, ast::Item::Fn(_) | ast::Item::Static(_) | ast::Item::Const(_)) + }) +} + +/// Returns whether the given nested function has generic parameters. +fn is_generic(function: &ast::Fn) -> bool { + function.generic_param_list().is_some() +} + +/// Returns whether the given nested function has any modifiers: +/// +/// - `async`, +/// - `const` or +/// - `unsafe` +fn has_modifiers(function: &ast::Fn) -> bool { + function.async_token().is_some() + || function.const_token().is_some() + || function.unsafe_token().is_some() +} + +/// Returns whether the given nested function has a trailing semicolon. +fn has_semicolon(function: &ast::Fn) -> bool { + function + .syntax() + .next_sibling_or_token() + .map(|t| t.kind() == SyntaxKind::SEMICOLON) + .unwrap_or(false) +} + +#[cfg(test)] +mod tests { + use crate::tests::{check_assist, check_assist_not_applicable}; + + use super::convert_nested_function_to_closure; + + #[test] + fn convert_nested_function_to_closure_works() { + check_assist( + convert_nested_function_to_closure, + r#" +fn main() { + fn $0foo(a: u64, b: u64) -> u64 { + 2 * (a + b) + } + + _ = foo(3, 4); +} + "#, + r#" +fn main() { + let foo = |a: u64, b: u64| { + 2 * (a + b) + }; + + _ = foo(3, 4); +} + "#, + ); + } + + #[test] + fn convert_nested_function_to_closure_works_with_existing_semicolon() { + check_assist( + convert_nested_function_to_closure, + r#" +fn main() { + fn foo$0(a: u64, b: u64) -> u64 { + 2 * (a + b) + }; + + _ = foo(3, 4); +} + "#, + r#" +fn main() { + let foo = |a: u64, b: u64| { + 2 * (a + b) + }; + + _ = foo(3, 4); +} + "#, + ); + } + + #[test] + fn convert_nested_function_to_closure_is_not_suggested_on_top_level_function() { + check_assist_not_applicable( + convert_nested_function_to_closure, + r#" +fn ma$0in() {} + "#, + ); + } + + #[test] + fn convert_nested_function_to_closure_is_not_suggested_when_cursor_off_name() { + check_assist_not_applicable( + convert_nested_function_to_closure, + r#" +fn main() { + fn foo(a: u64, $0b: u64) -> u64 { + 2 * (a + b) + } + + _ = foo(3, 4); +} + "#, + ); + } + + #[test] + fn convert_nested_function_to_closure_is_not_suggested_if_function_has_generic_params() { + check_assist_not_applicable( + convert_nested_function_to_closure, + r#" +fn main() { + fn fo$0o<S: Into<String>>(s: S) -> String { + s.into() + } + + _ = foo("hello"); +} + "#, + ); + } + + #[test] + fn convert_nested_function_to_closure_is_not_suggested_if_function_has_modifier() { + check_assist_not_applicable( + convert_nested_function_to_closure, + r#" +fn main() { + const fn fo$0o(s: String) -> String { + s + } + + _ = foo("hello"); +} + "#, + ); + } +} diff --git a/crates/ide-assists/src/lib.rs b/crates/ide-assists/src/lib.rs index 8b07e29a587..fc03903e593 100644 --- a/crates/ide-assists/src/lib.rs +++ b/crates/ide-assists/src/lib.rs @@ -122,6 +122,7 @@ mod handlers { mod convert_iter_for_each_to_for; mod convert_let_else_to_match; mod convert_match_to_let_else; + mod convert_nested_function_to_closure; mod convert_tuple_struct_to_named_struct; mod convert_named_struct_to_tuple_struct; mod convert_to_guarded_return; @@ -228,8 +229,9 @@ mod handlers { convert_iter_for_each_to_for::convert_iter_for_each_to_for, convert_iter_for_each_to_for::convert_for_loop_with_for_each, convert_let_else_to_match::convert_let_else_to_match, - convert_named_struct_to_tuple_struct::convert_named_struct_to_tuple_struct, convert_match_to_let_else::convert_match_to_let_else, + convert_named_struct_to_tuple_struct::convert_named_struct_to_tuple_struct, + convert_nested_function_to_closure::convert_nested_function_to_closure, convert_to_guarded_return::convert_to_guarded_return, convert_tuple_struct_to_named_struct::convert_tuple_struct_to_named_struct, convert_two_arm_bool_match_to_matches_macro::convert_two_arm_bool_match_to_matches_macro, diff --git a/crates/ide-assists/src/tests/generated.rs b/crates/ide-assists/src/tests/generated.rs index e2c71d2565c..f093dfddfae 100644 --- a/crates/ide-assists/src/tests/generated.rs +++ b/crates/ide-assists/src/tests/generated.rs @@ -495,6 +495,31 @@ impl Point { } #[test] +fn doctest_convert_nested_function_to_closure() { + check_doc_test( + "convert_nested_function_to_closure", + r#####" +fn main() { + fn fo$0o(label: &str, number: u64) { + println!("{}: {}", label, number); + } + + foo("Bar", 100); +} +"#####, + r#####" +fn main() { + let foo = |label: &str, number: u64| { + println!("{}: {}", label, number); + }; + + foo("Bar", 100); +} +"#####, + ) +} + +#[test] fn doctest_convert_to_guarded_return() { check_doc_test( "convert_to_guarded_return", |