bendns' repos / rust-analyzer
Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/ide_assists/src/handlers/convert_while_to_loop.rs')
-rw-r--r--crates/ide_assists/src/handlers/convert_while_to_loop.rs189
1 files changed, 189 insertions, 0 deletions
diff --git a/crates/ide_assists/src/handlers/convert_while_to_loop.rs b/crates/ide_assists/src/handlers/convert_while_to_loop.rs
new file mode 100644
index 0000000000..cbddc106ff
--- /dev/null
+++ b/crates/ide_assists/src/handlers/convert_while_to_loop.rs
@@ -0,0 +1,189 @@
+use std::iter::once;
+
+use syntax::{
+ ast::{
+ self,
+ edit::{AstNodeEdit, IndentLevel},
+ make, LoopBodyOwner,
+ },
+ AstNode, T,
+};
+
+use crate::{
+ assist_context::{AssistContext, Assists},
+ utils::invert_boolean_expression,
+ AssistId, AssistKind,
+};
+
+// Assist: convert_while_to_loop
+//
+// Replace a while with a loop.
+//
+// ```
+// fn main() {
+// $0while cond {
+// foo();
+// }
+// }
+// ```
+// ->
+// ```
+// fn main() {
+// loop {
+// if !cond {
+// break;
+// }
+// foo();
+// }
+// }
+// ```
+pub(crate) fn convert_while_to_loop(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+ let while_kw = ctx.find_token_syntax_at_offset(T![while])?;
+ let while_expr: ast::WhileExpr = while_kw.parent().and_then(ast::WhileExpr::cast)?;
+ let while_body = while_expr.loop_body()?;
+ let cond = while_expr.condition()?;
+
+ // Don't handle while let
+ if let Some(_) = cond.pat() {
+ return None;
+ };
+
+ let cond_expr = cond.expr()?;
+
+ let target = while_expr.syntax().text_range();
+ acc.add(
+ AssistId("convert_while_to_loop", AssistKind::RefactorRewrite),
+ "Convert while to loop",
+ target,
+ |edit| {
+ let while_indent_level = IndentLevel::from_node(while_expr.syntax());
+
+ let replacement = {
+ let if_expr = {
+ let cond = invert_boolean_expression(cond_expr);
+ let then_branch = make::block_expr(
+ once(make::expr_stmt(make::expr_break(None)).into()),
+ None,
+ );
+
+ make::expr_if(make::condition(cond, None), then_branch, None)
+ };
+
+ let if_expr = if_expr.indent(while_indent_level);
+ let stmts = once(make::expr_stmt(if_expr).into()).chain(while_body.statements());
+
+ let block_expr = make::block_expr(stmts, while_body.tail_expr());
+
+ let block_expr = block_expr.indent(while_indent_level);
+
+ make::expr_loop(block_expr)
+ };
+
+ edit.replace(target, replacement.syntax().text())
+ },
+ )
+}
+
+#[cfg(test)]
+mod tests {
+ use crate::tests::{check_assist, check_assist_not_applicable};
+
+ use super::*;
+
+ #[test]
+ fn convert_inside_fn() {
+ check_assist(
+ convert_while_to_loop,
+ r#"
+fn main() {
+ while$0 cond {
+ foo();
+ }
+}
+"#,
+ r#"
+fn main() {
+ loop {
+ if !cond {
+ break;
+ }
+ foo();
+ }
+}
+"#,
+ );
+ }
+
+ #[test]
+ fn convert_busy_wait() {
+ check_assist(
+ convert_while_to_loop,
+ r#"
+fn main() {
+ while$0 cond() {}
+}
+"#,
+ r#"
+fn main() {
+ loop {
+ if !cond() {
+ break;
+ }
+ }
+}
+"#,
+ );
+ }
+
+ #[test]
+ fn convert_trailing_expr() {
+ check_assist(
+ convert_while_to_loop,
+ r#"
+fn main() {
+ while$0 cond() {
+ bar()
+ }
+}
+"#,
+ r#"
+fn main() {
+ loop {
+ if !cond() {
+ break;
+ }
+ bar()
+ }
+}
+"#,
+ );
+ }
+
+ #[test]
+ fn ignore_while_let() {
+ check_assist_not_applicable(
+ convert_while_to_loop,
+ r#"
+fn main() {
+ while$0 let Some(_) = foo() {
+ bar();
+ }
+}
+"#,
+ );
+ }
+
+ #[test]
+ fn ignore_cursor_in_body() {
+ check_assist_not_applicable(
+ convert_while_to_loop,
+ r#"
+fn main() {
+ while cond {$0
+ bar();
+ }
+}
+"#,
+ );
+ }
+}