From ac226021cfd26a9332b5971f3e05118d77822af5 Mon Sep 17 00:00:00 2001
From: Aleksey Kladov <aleksey.kladov@gmail.com>
Date: Sun, 26 Aug 2018 12:09:28 +0300
Subject: scope based comletion

---
 crates/libeditor/src/code_actions.rs |  2 +-
 crates/libeditor/src/completion.rs   | 42 ++++++++++++++++++++++++++++++------
 crates/libeditor/tests/test.rs       | 34 ++++++++++++++---------------
 3 files changed, 53 insertions(+), 25 deletions(-)

(limited to 'crates/libeditor')

diff --git a/crates/libeditor/src/code_actions.rs b/crates/libeditor/src/code_actions.rs
index f53a8f9c6..e6ba83d2e 100644
--- a/crates/libeditor/src/code_actions.rs
+++ b/crates/libeditor/src/code_actions.rs
@@ -9,7 +9,7 @@ use libsyntax2::{
     SyntaxNodeRef,
     algo::{
         Direction, siblings,
-        find_leaf_at_offset, ancestors,
+        find_leaf_at_offset,
     },
 };
 
diff --git a/crates/libeditor/src/completion.rs b/crates/libeditor/src/completion.rs
index cf61ec784..16c9ead74 100644
--- a/crates/libeditor/src/completion.rs
+++ b/crates/libeditor/src/completion.rs
@@ -1,7 +1,11 @@
 use libsyntax2::{
-    File, TextUnit,
-    ast,
-    algo::find_leaf_at_offset,
+    File, TextUnit, AstNode, SyntaxNodeRef,
+    ast::{self, NameOwner},
+    algo::{
+        ancestors,
+        visit::{visitor_ctx, VisitorCtx},
+        walk::preorder,
+    },
 };
 
 use {
@@ -25,7 +29,33 @@ pub fn scope_completion(file: &File, offset: TextUnit) -> Option<Vec<CompletionI
 }
 
 fn complete(name_ref: ast::NameRef) -> Vec<CompletionItem> {
-    vec![CompletionItem {
-        name: "foo".to_string()
-    }]
+    let mut res = Vec::new();
+    for node in ancestors(name_ref.syntax()) {
+        process_scope(node, &mut res);
+    }
+    res
+}
+
+fn process_scope(node: SyntaxNodeRef, sink: &mut Vec<CompletionItem>) {
+    let _ = visitor_ctx(sink)
+        .visit::<ast::Block, _>(|block, sink| {
+            block.let_stmts()
+                .filter_map(|it| it.pat())
+                .for_each(move |it| process_pat(it, sink))
+        })
+        .visit::<ast::FnDef, _>(|fn_def, sink| {
+            fn_def.param_list().into_iter()
+                .flat_map(|it| it.params())
+                .filter_map(|it| it.pat())
+                .for_each(move |it| process_pat(it, sink))
+        })
+        .accept(node);
+
+    fn process_pat(pat: ast::Pat, sink: &mut Vec<CompletionItem>) {
+        let items = preorder(pat.syntax())
+            .filter_map(ast::BindPat::cast)
+            .filter_map(ast::BindPat::name)
+            .map(|name| CompletionItem { name: name.text().to_string() });
+        sink.extend(items);
+    }
 }
diff --git a/crates/libeditor/tests/test.rs b/crates/libeditor/tests/test.rs
index 20de2f240..ecdc149c7 100644
--- a/crates/libeditor/tests/test.rs
+++ b/crates/libeditor/tests/test.rs
@@ -256,25 +256,23 @@ struct Foo { f: u32 }
 ");
 }
 
-// #[test]
-// fn test_completion() {
-//     fn do_check(code: &str, expected_completions: &str) {
-//         let (off, code) = extract_offset(&code);
-//         let file = file(&code);
-//         let completions = scope_completion(&file, off).unwrap();
-//         assert_eq_dbg(expected_completions, &completions);
-//     }
+#[test]
+fn test_completion() {
+    fn do_check(code: &str, expected_completions: &str) {
+        let (off, code) = extract_offset(&code);
+        let file = file(&code);
+        let completions = scope_completion(&file, off).unwrap();
+        assert_eq_dbg(expected_completions, &completions);
+    }
 
-//     do_check(r"
-// fn foo(foo: i32) {
-//     let bar = 92;
-//     1 + <|>
-// }
-// ", r#"
-// CompletionItem { name: "bar" },
-// CompletionItem { name: "foo" },
-// "#);
-// }
+    do_check(r"
+fn quux(x: i32) {
+    let y = 92;
+    1 + <|>
+}
+", r#"[CompletionItem { name: "y" },
+       CompletionItem { name: "x" }]"#);
+}
 
 fn file(text: &str) -> File {
     File::parse(text)
-- 
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