postfix completion

crates/ra_ide_api/src/completion/complete_postfix.rs

@@ -0,0 +1,95 @@
+use crate::{
+    completion::{
+        completion_item::{
+            Completions,
+            Builder,
+            CompletionKind,
+        },
+        completion_context::CompletionContext,
+    },
+    CompletionItem
+};
+use ra_syntax::{
+    ast::AstNode,
+    TextRange
+};
+use ra_text_edit::TextEditBuilder;
+
+fn postfix_snippet(ctx: &CompletionContext, label: &str, snippet: &str) -> Builder {
+    let replace_range = ctx.source_range();
+    let receiver_range = ctx
+        .dot_receiver
+        .expect("no receiver available")
+        .syntax()
+        .range();
+    let delete_range = TextRange::from_to(receiver_range.start(), replace_range.start());
+    let mut builder = TextEditBuilder::default();
+    builder.delete(delete_range);
+    CompletionItem::new(CompletionKind::Postfix, replace_range, label)
+        .snippet(snippet)
+        .text_edit(builder.finish())
+}
+
+pub(super) fn complete_postfix(acc: &mut Completions, ctx: &CompletionContext) {
+    if let Some(dot_receiver) = ctx.dot_receiver {
+        let receiver_text = dot_receiver.syntax().text().to_string();
+        postfix_snippet(ctx, "not", "!not").add_to(acc);
+        postfix_snippet(ctx, "if", &format!("if {} {{$0}}", receiver_text)).add_to(acc);
+        postfix_snippet(
+            ctx,
+            "match",
+            &format!("match {} {{\n${{1:_}} => {{$0\\}},\n}}", receiver_text),
+        )
+        .add_to(acc);
+        postfix_snippet(ctx, "while", &format!("while {} {{\n$0\n}}", receiver_text)).add_to(acc);
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::completion::completion_item::CompletionKind;
+    use crate::completion::completion_item::check_completion;
+
+    fn check_snippet_completion(code: &str, expected_completions: &str) {
+        check_completion(code, expected_completions, CompletionKind::Postfix);
+    }
+
+    #[test]
+    fn test_filter_postfix_completion1() {
+        check_snippet_completion(
+            "filter_postfix_completion1",
+            r#"
+            fn main() {
+                let bar = "a";
+                bar.<|>
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn test_filter_postfix_completion2() {
+        check_snippet_completion(
+            "filter_postfix_completion2",
+            r#"
+            fn main() {
+                let bar = "a";
+                bar.i<|>
+            }
+            "#,
+        );
+    }
+
+    #[test]
+    fn test_filter_postfix_completion3() {
+        check_snippet_completion(
+            "filter_postfix_completion3",
+            r#"
+            fn main() {
+                let bar = "a";
+                bar.if<|>
+            }
+            "#,
+        );
+    }
+}