From 561b4b11ff1d87ea1ff2477dcba6ae1f396573a3 Mon Sep 17 00:00:00 2001 From: Aleksey Kladov Date: Fri, 7 Feb 2020 15:53:31 +0100 Subject: Name assist handlers --- crates/ra_assists/src/handlers/early_return.rs | 505 +++++++++++++++++++++++++ 1 file changed, 505 insertions(+) create mode 100644 crates/ra_assists/src/handlers/early_return.rs (limited to 'crates/ra_assists/src/handlers/early_return.rs') diff --git a/crates/ra_assists/src/handlers/early_return.rs b/crates/ra_assists/src/handlers/early_return.rs new file mode 100644 index 000000000..8eb3bd473 --- /dev/null +++ b/crates/ra_assists/src/handlers/early_return.rs @@ -0,0 +1,505 @@ +use std::{iter::once, ops::RangeInclusive}; + +use ra_syntax::{ + algo::replace_children, + ast::{self, edit::IndentLevel, make, Block, Pat::TupleStructPat}, + AstNode, + SyntaxKind::{FN_DEF, LOOP_EXPR, L_CURLY, R_CURLY, WHILE_EXPR, WHITESPACE}, + SyntaxNode, +}; + +use crate::{ + assist_ctx::{Assist, AssistCtx}, + handlers::invert_if::invert_boolean_expression, + AssistId, +}; + +// Assist: convert_to_guarded_return +// +// Replace a large conditional with a guarded return. +// +// ``` +// fn main() { +// <|>if cond { +// foo(); +// bar(); +// } +// } +// ``` +// -> +// ``` +// fn main() { +// if !cond { +// return; +// } +// foo(); +// bar(); +// } +// ``` +pub(crate) fn convert_to_guarded_return(ctx: AssistCtx) -> Option { + let if_expr: ast::IfExpr = ctx.find_node_at_offset()?; + if if_expr.else_branch().is_some() { + return None; + } + + let cond = if_expr.condition()?; + + // Check if there is an IfLet that we can handle. + let if_let_pat = match cond.pat() { + None => None, // No IfLet, supported. + Some(TupleStructPat(pat)) if pat.args().count() == 1 => { + let path = pat.path()?; + match path.qualifier() { + None => { + let bound_ident = pat.args().next().unwrap(); + Some((path, bound_ident)) + } + Some(_) => return None, + } + } + Some(_) => return None, // Unsupported IfLet. + }; + + let cond_expr = cond.expr()?; + let then_block = if_expr.then_branch()?.block()?; + + let parent_block = if_expr.syntax().parent()?.ancestors().find_map(ast::Block::cast)?; + + if parent_block.expr()? != if_expr.clone().into() { + return None; + } + + // check for early return and continue + let first_in_then_block = then_block.syntax().first_child()?; + if ast::ReturnExpr::can_cast(first_in_then_block.kind()) + || ast::ContinueExpr::can_cast(first_in_then_block.kind()) + || first_in_then_block + .children() + .any(|x| ast::ReturnExpr::can_cast(x.kind()) || ast::ContinueExpr::can_cast(x.kind())) + { + return None; + } + + let parent_container = parent_block.syntax().parent()?.parent()?; + + let early_expression: ast::Expr = match parent_container.kind() { + WHILE_EXPR | LOOP_EXPR => make::expr_continue(), + FN_DEF => make::expr_return(), + _ => return None, + }; + + if then_block.syntax().first_child_or_token().map(|t| t.kind() == L_CURLY).is_none() { + return None; + } + + then_block.syntax().last_child_or_token().filter(|t| t.kind() == R_CURLY)?; + let cursor_position = ctx.frange.range.start(); + + ctx.add_assist(AssistId("convert_to_guarded_return"), "Convert to guarded return", |edit| { + let if_indent_level = IndentLevel::from_node(&if_expr.syntax()); + let new_block = match if_let_pat { + None => { + // If. + let new_expr = { + let then_branch = + make::block_expr(once(make::expr_stmt(early_expression).into()), None); + let cond = invert_boolean_expression(cond_expr); + let e = make::expr_if(cond, then_branch); + if_indent_level.increase_indent(e) + }; + replace(new_expr.syntax(), &then_block, &parent_block, &if_expr) + } + Some((path, bound_ident)) => { + // If-let. + let match_expr = { + let happy_arm = make::match_arm( + once( + make::tuple_struct_pat( + path, + once(make::bind_pat(make::name("it")).into()), + ) + .into(), + ), + make::expr_path(make::path_from_name_ref(make::name_ref("it"))), + ); + + let sad_arm = make::match_arm( + // FIXME: would be cool to use `None` or `Err(_)` if appropriate + once(make::placeholder_pat().into()), + early_expression, + ); + + make::expr_match(cond_expr, make::match_arm_list(vec![happy_arm, sad_arm])) + }; + + let let_stmt = make::let_stmt( + make::bind_pat(make::name(&bound_ident.syntax().to_string())).into(), + Some(match_expr), + ); + let let_stmt = if_indent_level.increase_indent(let_stmt); + replace(let_stmt.syntax(), &then_block, &parent_block, &if_expr) + } + }; + edit.target(if_expr.syntax().text_range()); + edit.replace_ast(parent_block, ast::Block::cast(new_block).unwrap()); + edit.set_cursor(cursor_position); + + fn replace( + new_expr: &SyntaxNode, + then_block: &Block, + parent_block: &Block, + if_expr: &ast::IfExpr, + ) -> SyntaxNode { + let then_block_items = IndentLevel::from(1).decrease_indent(then_block.clone()); + let end_of_then = then_block_items.syntax().last_child_or_token().unwrap(); + let end_of_then = + if end_of_then.prev_sibling_or_token().map(|n| n.kind()) == Some(WHITESPACE) { + end_of_then.prev_sibling_or_token().unwrap() + } else { + end_of_then + }; + let mut then_statements = new_expr.children_with_tokens().chain( + then_block_items + .syntax() + .children_with_tokens() + .skip(1) + .take_while(|i| *i != end_of_then), + ); + replace_children( + &parent_block.syntax(), + RangeInclusive::new( + if_expr.clone().syntax().clone().into(), + if_expr.syntax().clone().into(), + ), + &mut then_statements, + ) + } + }) +} + +#[cfg(test)] +mod tests { + use crate::helpers::{check_assist, check_assist_not_applicable}; + + use super::*; + + #[test] + fn convert_inside_fn() { + check_assist( + convert_to_guarded_return, + r#" + fn main() { + bar(); + if<|> true { + foo(); + + //comment + bar(); + } + } + "#, + r#" + fn main() { + bar(); + if<|> !true { + return; + } + foo(); + + //comment + bar(); + } + "#, + ); + } + + #[test] + fn convert_let_inside_fn() { + check_assist( + convert_to_guarded_return, + r#" + fn main(n: Option) { + bar(); + if<|> let Some(n) = n { + foo(n); + + //comment + bar(); + } + } + "#, + r#" + fn main(n: Option) { + bar(); + le<|>t n = match n { + Some(it) => it, + _ => return, + }; + foo(n); + + //comment + bar(); + } + "#, + ); + } + + #[test] + fn convert_if_let_result() { + check_assist( + convert_to_guarded_return, + r#" + fn main() { + if<|> let Ok(x) = Err(92) { + foo(x); + } + } + "#, + r#" + fn main() { + le<|>t x = match Err(92) { + Ok(it) => it, + _ => return, + }; + foo(x); + } + "#, + ); + } + + #[test] + fn convert_let_ok_inside_fn() { + check_assist( + convert_to_guarded_return, + r#" + fn main(n: Option) { + bar(); + if<|> let Ok(n) = n { + foo(n); + + //comment + bar(); + } + } + "#, + r#" + fn main(n: Option) { + bar(); + le<|>t n = match n { + Ok(it) => it, + _ => return, + }; + foo(n); + + //comment + bar(); + } + "#, + ); + } + + #[test] + fn convert_inside_while() { + check_assist( + convert_to_guarded_return, + r#" + fn main() { + while true { + if<|> true { + foo(); + bar(); + } + } + } + "#, + r#" + fn main() { + while true { + if<|> !true { + continue; + } + foo(); + bar(); + } + } + "#, + ); + } + + #[test] + fn convert_let_inside_while() { + check_assist( + convert_to_guarded_return, + r#" + fn main() { + while true { + if<|> let Some(n) = n { + foo(n); + bar(); + } + } + } + "#, + r#" + fn main() { + while true { + le<|>t n = match n { + Some(it) => it, + _ => continue, + }; + foo(n); + bar(); + } + } + "#, + ); + } + + #[test] + fn convert_inside_loop() { + check_assist( + convert_to_guarded_return, + r#" + fn main() { + loop { + if<|> true { + foo(); + bar(); + } + } + } + "#, + r#" + fn main() { + loop { + if<|> !true { + continue; + } + foo(); + bar(); + } + } + "#, + ); + } + + #[test] + fn convert_let_inside_loop() { + check_assist( + convert_to_guarded_return, + r#" + fn main() { + loop { + if<|> let Some(n) = n { + foo(n); + bar(); + } + } + } + "#, + r#" + fn main() { + loop { + le<|>t n = match n { + Some(it) => it, + _ => continue, + }; + foo(n); + bar(); + } + } + "#, + ); + } + + #[test] + fn ignore_already_converted_if() { + check_assist_not_applicable( + convert_to_guarded_return, + r#" + fn main() { + if<|> true { + return; + } + } + "#, + ); + } + + #[test] + fn ignore_already_converted_loop() { + check_assist_not_applicable( + convert_to_guarded_return, + r#" + fn main() { + loop { + if<|> true { + continue; + } + } + } + "#, + ); + } + + #[test] + fn ignore_return() { + check_assist_not_applicable( + convert_to_guarded_return, + r#" + fn main() { + if<|> true { + return + } + } + "#, + ); + } + + #[test] + fn ignore_else_branch() { + check_assist_not_applicable( + convert_to_guarded_return, + r#" + fn main() { + if<|> true { + foo(); + } else { + bar() + } + } + "#, + ); + } + + #[test] + fn ignore_statements_aftert_if() { + check_assist_not_applicable( + convert_to_guarded_return, + r#" + fn main() { + if<|> true { + foo(); + } + bar(); + } + "#, + ); + } + + #[test] + fn ignore_statements_inside_if() { + check_assist_not_applicable( + convert_to_guarded_return, + r#" + fn main() { + if false { + if<|> true { + foo(); + } + } + } + "#, + ); + } +} -- cgit v1.2.3 From d00add1f1fec59494c3c1a99c27937ae3891458d Mon Sep 17 00:00:00 2001 From: Aleksey Kladov Date: Fri, 7 Feb 2020 15:57:38 +0100 Subject: Introduce assists utils --- crates/ra_assists/src/handlers/early_return.rs | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'crates/ra_assists/src/handlers/early_return.rs') diff --git a/crates/ra_assists/src/handlers/early_return.rs b/crates/ra_assists/src/handlers/early_return.rs index 8eb3bd473..22f88884f 100644 --- a/crates/ra_assists/src/handlers/early_return.rs +++ b/crates/ra_assists/src/handlers/early_return.rs @@ -10,7 +10,7 @@ use ra_syntax::{ use crate::{ assist_ctx::{Assist, AssistCtx}, - handlers::invert_if::invert_boolean_expression, + utils::invert_boolean_expression, AssistId, }; -- cgit v1.2.3