use ra_syntax::{ ast, ast::{AstNode, AstToken, IfExpr, MatchArm}, TextSize, }; use crate::{Assist, AssistCtx, AssistId}; // Assist: move_guard_to_arm_body // // Moves match guard into match arm body. // // ``` // enum Action { Move { distance: u32 }, Stop } // // fn handle(action: Action) { // match action { // Action::Move { distance } <|>if distance > 10 => foo(), // _ => (), // } // } // ``` // -> // ``` // enum Action { Move { distance: u32 }, Stop } // // fn handle(action: Action) { // match action { // Action::Move { distance } => if distance > 10 { foo() }, // _ => (), // } // } // ``` pub(crate) fn move_guard_to_arm_body(ctx: AssistCtx) -> Option { let match_arm = ctx.find_node_at_offset::()?; let guard = match_arm.guard()?; let space_before_guard = guard.syntax().prev_sibling_or_token(); let guard_conditions = guard.expr()?; let arm_expr = match_arm.expr()?; let buf = format!("if {} {{ {} }}", guard_conditions.syntax().text(), arm_expr.syntax().text()); ctx.add_assist(AssistId("move_guard_to_arm_body"), "Move guard to arm body", |edit| { edit.target(guard.syntax().text_range()); let offseting_amount = match space_before_guard.and_then(|it| it.into_token()) { Some(tok) => { if ast::Whitespace::cast(tok.clone()).is_some() { let ele = tok.text_range(); edit.delete(ele); ele.len() } else { TextSize::from(0) } } _ => TextSize::from(0), }; edit.delete(guard.syntax().text_range()); edit.replace_node_and_indent(arm_expr.syntax(), buf); edit.set_cursor( arm_expr.syntax().text_range().start() + TextSize::from(3) - offseting_amount, ); }) } // Assist: move_arm_cond_to_match_guard // // Moves if expression from match arm body into a guard. // // ``` // enum Action { Move { distance: u32 }, Stop } // // fn handle(action: Action) { // match action { // Action::Move { distance } => <|>if distance > 10 { foo() }, // _ => (), // } // } // ``` // -> // ``` // enum Action { Move { distance: u32 }, Stop } // // fn handle(action: Action) { // match action { // Action::Move { distance } if distance > 10 => foo(), // _ => (), // } // } // ``` pub(crate) fn move_arm_cond_to_match_guard(ctx: AssistCtx) -> Option { let match_arm: MatchArm = ctx.find_node_at_offset::()?; let match_pat = match_arm.pat()?; let arm_body = match_arm.expr()?; let if_expr: IfExpr = IfExpr::cast(arm_body.syntax().clone())?; let cond = if_expr.condition()?; let then_block = if_expr.then_branch()?; // Not support if with else branch if if_expr.else_branch().is_some() { return None; } // Not support moving if let to arm guard if cond.pat().is_some() { return None; } let buf = format!(" if {}", cond.syntax().text()); ctx.add_assist( AssistId("move_arm_cond_to_match_guard"), "Move condition to match guard", |edit| { edit.target(if_expr.syntax().text_range()); let then_only_expr = then_block.statements().next().is_none(); match &then_block.expr() { Some(then_expr) if then_only_expr => { edit.replace(if_expr.syntax().text_range(), then_expr.syntax().text()) } _ => edit.replace(if_expr.syntax().text_range(), then_block.syntax().text()), } edit.insert(match_pat.syntax().text_range().end(), buf); edit.set_cursor(match_pat.syntax().text_range().end() + TextSize::from(1)); }, ) } #[cfg(test)] mod tests { use super::*; use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target}; #[test] fn move_guard_to_arm_body_target() { check_assist_target( move_guard_to_arm_body, r#" fn f() { let t = 'a'; let chars = "abcd"; match t { '\r' <|>if chars.clone().next() == Some('\n') => false, _ => true } } "#, r#"if chars.clone().next() == Some('\n')"#, ); } #[test] fn move_guard_to_arm_body_works() { check_assist( move_guard_to_arm_body, r#" fn f() { let t = 'a'; let chars = "abcd"; match t { '\r' <|>if chars.clone().next() == Some('\n') => false, _ => true } } "#, r#" fn f() { let t = 'a'; let chars = "abcd"; match t { '\r' => if chars.clone().next() == Some('\n') { <|>false }, _ => true } } "#, ); } #[test] fn move_guard_to_arm_body_works_complex_match() { check_assist( move_guard_to_arm_body, r#" fn f() { match x { <|>y @ 4 | y @ 5 if y > 5 => true, _ => false } } "#, r#" fn f() { match x { y @ 4 | y @ 5 => if y > 5 { <|>true }, _ => false } } "#, ); } #[test] fn move_arm_cond_to_match_guard_works() { check_assist( move_arm_cond_to_match_guard, r#" fn f() { let t = 'a'; let chars = "abcd"; match t { '\r' => if chars.clone().next() == Some('\n') { <|>false }, _ => true } } "#, r#" fn f() { let t = 'a'; let chars = "abcd"; match t { '\r' <|>if chars.clone().next() == Some('\n') => false, _ => true } } "#, ); } #[test] fn move_arm_cond_to_match_guard_if_let_not_works() { check_assist_not_applicable( move_arm_cond_to_match_guard, r#" fn f() { let t = 'a'; let chars = "abcd"; match t { '\r' => if let Some(_) = chars.clone().next() { <|>false }, _ => true } } "#, ); } #[test] fn move_arm_cond_to_match_guard_if_empty_body_works() { check_assist( move_arm_cond_to_match_guard, r#" fn f() { let t = 'a'; let chars = "abcd"; match t { '\r' => if chars.clone().next().is_some() { <|> }, _ => true } } "#, r#" fn f() { let t = 'a'; let chars = "abcd"; match t { '\r' <|>if chars.clone().next().is_some() => { }, _ => true } } "#, ); } #[test] fn move_arm_cond_to_match_guard_if_multiline_body_works() { check_assist( move_arm_cond_to_match_guard, r#" fn f() { let mut t = 'a'; let chars = "abcd"; match t { '\r' => if chars.clone().next().is_some() { t = 'e';<|> false }, _ => true } } "#, r#" fn f() { let mut t = 'a'; let chars = "abcd"; match t { '\r' <|>if chars.clone().next().is_some() => { t = 'e'; false }, _ => true } } "#, ); } }