From fc34403018079ea053f26d0a31b7517053c7dd8c Mon Sep 17 00:00:00 2001 From: Aleksey Kladov Date: Thu, 13 Aug 2020 17:33:38 +0200 Subject: Rename ra_assists -> assists --- crates/assists/src/handlers/extract_variable.rs | 588 ++++++++++++++++++++++++ 1 file changed, 588 insertions(+) create mode 100644 crates/assists/src/handlers/extract_variable.rs (limited to 'crates/assists/src/handlers/extract_variable.rs') diff --git a/crates/assists/src/handlers/extract_variable.rs b/crates/assists/src/handlers/extract_variable.rs new file mode 100644 index 000000000..d2ae137cd --- /dev/null +++ b/crates/assists/src/handlers/extract_variable.rs @@ -0,0 +1,588 @@ +use stdx::format_to; +use syntax::{ + ast::{self, AstNode}, + SyntaxKind::{ + BLOCK_EXPR, BREAK_EXPR, CLOSURE_EXPR, COMMENT, LOOP_EXPR, MATCH_ARM, PATH_EXPR, RETURN_EXPR, + }, + SyntaxNode, +}; +use test_utils::mark; + +use crate::{AssistContext, AssistId, AssistKind, Assists}; + +// Assist: extract_variable +// +// Extracts subexpression into a variable. +// +// ``` +// fn main() { +// <|>(1 + 2)<|> * 4; +// } +// ``` +// -> +// ``` +// fn main() { +// let $0var_name = (1 + 2); +// var_name * 4; +// } +// ``` +pub(crate) fn extract_variable(acc: &mut Assists, ctx: &AssistContext) -> Option<()> { + if ctx.frange.range.is_empty() { + return None; + } + let node = ctx.covering_element(); + if node.kind() == COMMENT { + mark::hit!(extract_var_in_comment_is_not_applicable); + return None; + } + let to_extract = node.ancestors().find_map(valid_target_expr)?; + let anchor = Anchor::from(&to_extract)?; + let indent = anchor.syntax().prev_sibling_or_token()?.as_token()?.clone(); + let target = to_extract.syntax().text_range(); + acc.add( + AssistId("extract_variable", AssistKind::RefactorExtract), + "Extract into variable", + target, + move |edit| { + let field_shorthand = + match to_extract.syntax().parent().and_then(ast::RecordExprField::cast) { + Some(field) => field.name_ref(), + None => None, + }; + + let mut buf = String::new(); + + let var_name = match &field_shorthand { + Some(it) => it.to_string(), + None => "var_name".to_string(), + }; + let expr_range = match &field_shorthand { + Some(it) => it.syntax().text_range().cover(to_extract.syntax().text_range()), + None => to_extract.syntax().text_range(), + }; + + if let Anchor::WrapInBlock(_) = anchor { + format_to!(buf, "{{ let {} = ", var_name); + } else { + format_to!(buf, "let {} = ", var_name); + }; + format_to!(buf, "{}", to_extract.syntax()); + + if let Anchor::Replace(stmt) = anchor { + mark::hit!(test_extract_var_expr_stmt); + if stmt.semicolon_token().is_none() { + buf.push_str(";"); + } + match ctx.config.snippet_cap { + Some(cap) => { + let snip = buf + .replace(&format!("let {}", var_name), &format!("let $0{}", var_name)); + edit.replace_snippet(cap, expr_range, snip) + } + None => edit.replace(expr_range, buf), + } + return; + } + + buf.push_str(";"); + + // We want to maintain the indent level, + // but we do not want to duplicate possible + // extra newlines in the indent block + let text = indent.text(); + if text.starts_with('\n') { + buf.push_str("\n"); + buf.push_str(text.trim_start_matches('\n')); + } else { + buf.push_str(text); + } + + edit.replace(expr_range, var_name.clone()); + let offset = anchor.syntax().text_range().start(); + match ctx.config.snippet_cap { + Some(cap) => { + let snip = + buf.replace(&format!("let {}", var_name), &format!("let $0{}", var_name)); + edit.insert_snippet(cap, offset, snip) + } + None => edit.insert(offset, buf), + } + + if let Anchor::WrapInBlock(_) = anchor { + edit.insert(anchor.syntax().text_range().end(), " }"); + } + }, + ) +} + +/// Check whether the node is a valid expression which can be extracted to a variable. +/// In general that's true for any expression, but in some cases that would produce invalid code. +fn valid_target_expr(node: SyntaxNode) -> Option { + match node.kind() { + PATH_EXPR | LOOP_EXPR => None, + BREAK_EXPR => ast::BreakExpr::cast(node).and_then(|e| e.expr()), + RETURN_EXPR => ast::ReturnExpr::cast(node).and_then(|e| e.expr()), + BLOCK_EXPR => { + ast::BlockExpr::cast(node).filter(|it| it.is_standalone()).map(ast::Expr::from) + } + _ => ast::Expr::cast(node), + } +} + +enum Anchor { + Before(SyntaxNode), + Replace(ast::ExprStmt), + WrapInBlock(SyntaxNode), +} + +impl Anchor { + fn from(to_extract: &ast::Expr) -> Option { + to_extract.syntax().ancestors().find_map(|node| { + if let Some(expr) = + node.parent().and_then(ast::BlockExpr::cast).and_then(|it| it.expr()) + { + if expr.syntax() == &node { + mark::hit!(test_extract_var_last_expr); + return Some(Anchor::Before(node)); + } + } + + if let Some(parent) = node.parent() { + if parent.kind() == MATCH_ARM || parent.kind() == CLOSURE_EXPR { + return Some(Anchor::WrapInBlock(node)); + } + } + + if let Some(stmt) = ast::Stmt::cast(node.clone()) { + if let ast::Stmt::ExprStmt(stmt) = stmt { + if stmt.expr().as_ref() == Some(to_extract) { + return Some(Anchor::Replace(stmt)); + } + } + return Some(Anchor::Before(node)); + } + None + }) + } + + fn syntax(&self) -> &SyntaxNode { + match self { + Anchor::Before(it) | Anchor::WrapInBlock(it) => it, + Anchor::Replace(stmt) => stmt.syntax(), + } + } +} + +#[cfg(test)] +mod tests { + use test_utils::mark; + + use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target}; + + use super::*; + + #[test] + fn test_extract_var_simple() { + check_assist( + extract_variable, + r#" +fn foo() { + foo(<|>1 + 1<|>); +}"#, + r#" +fn foo() { + let $0var_name = 1 + 1; + foo(var_name); +}"#, + ); + } + + #[test] + fn extract_var_in_comment_is_not_applicable() { + mark::check!(extract_var_in_comment_is_not_applicable); + check_assist_not_applicable(extract_variable, "fn main() { 1 + /* <|>comment<|> */ 1; }"); + } + + #[test] + fn test_extract_var_expr_stmt() { + mark::check!(test_extract_var_expr_stmt); + check_assist( + extract_variable, + r#" +fn foo() { + <|>1 + 1<|>; +}"#, + r#" +fn foo() { + let $0var_name = 1 + 1; +}"#, + ); + check_assist( + extract_variable, + " +fn foo() { + <|>{ let x = 0; x }<|> + something_else(); +}", + " +fn foo() { + let $0var_name = { let x = 0; x }; + something_else(); +}", + ); + } + + #[test] + fn test_extract_var_part_of_expr_stmt() { + check_assist( + extract_variable, + " +fn foo() { + <|>1<|> + 1; +}", + " +fn foo() { + let $0var_name = 1; + var_name + 1; +}", + ); + } + + #[test] + fn test_extract_var_last_expr() { + mark::check!(test_extract_var_last_expr); + check_assist( + extract_variable, + r#" +fn foo() { + bar(<|>1 + 1<|>) +} +"#, + r#" +fn foo() { + let $0var_name = 1 + 1; + bar(var_name) +} +"#, + ); + check_assist( + extract_variable, + r#" +fn foo() { + <|>bar(1 + 1)<|> +} +"#, + r#" +fn foo() { + let $0var_name = bar(1 + 1); + var_name +} +"#, + ) + } + + #[test] + fn test_extract_var_in_match_arm_no_block() { + check_assist( + extract_variable, + " +fn main() { + let x = true; + let tuple = match x { + true => (<|>2 + 2<|>, true) + _ => (0, false) + }; +} +", + " +fn main() { + let x = true; + let tuple = match x { + true => { let $0var_name = 2 + 2; (var_name, true) } + _ => (0, false) + }; +} +", + ); + } + + #[test] + fn test_extract_var_in_match_arm_with_block() { + check_assist( + extract_variable, + " +fn main() { + let x = true; + let tuple = match x { + true => { + let y = 1; + (<|>2 + y<|>, true) + } + _ => (0, false) + }; +} +", + " +fn main() { + let x = true; + let tuple = match x { + true => { + let y = 1; + let $0var_name = 2 + y; + (var_name, true) + } + _ => (0, false) + }; +} +", + ); + } + + #[test] + fn test_extract_var_in_closure_no_block() { + check_assist( + extract_variable, + " +fn main() { + let lambda = |x: u32| <|>x * 2<|>; +} +", + " +fn main() { + let lambda = |x: u32| { let $0var_name = x * 2; var_name }; +} +", + ); + } + + #[test] + fn test_extract_var_in_closure_with_block() { + check_assist( + extract_variable, + " +fn main() { + let lambda = |x: u32| { <|>x * 2<|> }; +} +", + " +fn main() { + let lambda = |x: u32| { let $0var_name = x * 2; var_name }; +} +", + ); + } + + #[test] + fn test_extract_var_path_simple() { + check_assist( + extract_variable, + " +fn main() { + let o = <|>Some(true)<|>; +} +", + " +fn main() { + let $0var_name = Some(true); + let o = var_name; +} +", + ); + } + + #[test] + fn test_extract_var_path_method() { + check_assist( + extract_variable, + " +fn main() { + let v = <|>bar.foo()<|>; +} +", + " +fn main() { + let $0var_name = bar.foo(); + let v = var_name; +} +", + ); + } + + #[test] + fn test_extract_var_return() { + check_assist( + extract_variable, + " +fn foo() -> u32 { + <|>return 2 + 2<|>; +} +", + " +fn foo() -> u32 { + let $0var_name = 2 + 2; + return var_name; +} +", + ); + } + + #[test] + fn test_extract_var_does_not_add_extra_whitespace() { + check_assist( + extract_variable, + " +fn foo() -> u32 { + + + <|>return 2 + 2<|>; +} +", + " +fn foo() -> u32 { + + + let $0var_name = 2 + 2; + return var_name; +} +", + ); + + check_assist( + extract_variable, + " +fn foo() -> u32 { + + <|>return 2 + 2<|>; +} +", + " +fn foo() -> u32 { + + let $0var_name = 2 + 2; + return var_name; +} +", + ); + + check_assist( + extract_variable, + " +fn foo() -> u32 { + let foo = 1; + + // bar + + + <|>return 2 + 2<|>; +} +", + " +fn foo() -> u32 { + let foo = 1; + + // bar + + + let $0var_name = 2 + 2; + return var_name; +} +", + ); + } + + #[test] + fn test_extract_var_break() { + check_assist( + extract_variable, + " +fn main() { + let result = loop { + <|>break 2 + 2<|>; + }; +} +", + " +fn main() { + let result = loop { + let $0var_name = 2 + 2; + break var_name; + }; +} +", + ); + } + + #[test] + fn test_extract_var_for_cast() { + check_assist( + extract_variable, + " +fn main() { + let v = <|>0f32 as u32<|>; +} +", + " +fn main() { + let $0var_name = 0f32 as u32; + let v = var_name; +} +", + ); + } + + #[test] + fn extract_var_field_shorthand() { + check_assist( + extract_variable, + r#" +struct S { + foo: i32 +} + +fn main() { + S { foo: <|>1 + 1<|> } +} +"#, + r#" +struct S { + foo: i32 +} + +fn main() { + let $0foo = 1 + 1; + S { foo } +} +"#, + ) + } + + #[test] + fn test_extract_var_for_return_not_applicable() { + check_assist_not_applicable(extract_variable, "fn foo() { <|>return<|>; } "); + } + + #[test] + fn test_extract_var_for_break_not_applicable() { + check_assist_not_applicable(extract_variable, "fn main() { loop { <|>break<|>; }; }"); + } + + // FIXME: This is not quite correct, but good enough(tm) for the sorting heuristic + #[test] + fn extract_var_target() { + check_assist_target(extract_variable, "fn foo() -> u32 { <|>return 2 + 2<|>; }", "2 + 2"); + + check_assist_target( + extract_variable, + " +fn main() { + let x = true; + let tuple = match x { + true => (<|>2 + 2<|>, true) + _ => (0, false) + }; +} +", + "2 + 2", + ); + } +} -- cgit v1.2.3