From 6d111d4bd78f340b397a5f45dc8c22a245f676e0 Mon Sep 17 00:00:00 2001
From: Maxime Coste <mawww@kakoune.org>
Date: Tue, 20 Feb 2018 22:09:03 +1100
Subject: [PATCH] Re-introduce aliases in command name completion

Aliases are considered again in command name completion, but only
if they are more than 3 charactes long. This should prevent cluttering
with aliases while still letting long ones being completed.
---
 src/alias_registry.hh  | 16 +++++++++++++++-
 src/command_manager.cc |  6 +++++-
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/src/alias_registry.hh b/src/alias_registry.hh
index 49571c1e..952669a0 100644
--- a/src/alias_registry.hh
+++ b/src/alias_registry.hh
@@ -18,12 +18,26 @@ public:
 
     Vector<StringView> aliases_for(StringView command) const;
 
+    auto flatten_aliases() const
+    {
+        auto merge = [](auto&& first, const AliasMap& second) {
+            return concatenated(std::forward<decltype(first)>(first)
+                                | filter([&second](auto& i) { return not second.contains(i.key); }),
+                                second);
+        };
+        static const AliasMap empty;
+        auto& parent = m_parent ? m_parent->m_aliases : empty;
+        auto& grand_parent = (m_parent and m_parent->m_parent) ? m_parent->m_parent->m_aliases : empty;
+        return merge(merge(grand_parent, parent), m_aliases);
+    }
+
 private:
     friend class Scope;
     AliasRegistry() {}
 
     SafePtr<AliasRegistry> m_parent;
-    HashMap<String, String, MemoryDomain::Aliases> m_aliases;
+    using AliasMap = HashMap<String, String, MemoryDomain::Aliases>;
+    AliasMap m_aliases;
 };
 
 }
diff --git a/src/command_manager.cc b/src/command_manager.cc
index ed489183..45200e11 100644
--- a/src/command_manager.cc
+++ b/src/command_manager.cc
@@ -540,7 +540,11 @@ Completions CommandManager::complete_command_name(const Context& context, String
             | filter([](const CommandMap::Item& cmd) { return not (cmd.value.flags & CommandFlags::Hidden); })
             | transform(std::mem_fn(&CommandMap::Item::key));
 
-    return {0, query.length(), Kakoune::complete(query, query.length(), commands)};
+    auto aliases = context.aliases().flatten_aliases()
+            | transform(std::mem_fn(&HashItem<String, String>::key))
+            | filter([](auto& alias) { return alias.length() > 3; });
+
+    return {0, query.length(), Kakoune::complete(query, query.length(), concatenated(commands, aliases))};
 }
 
 Completions CommandManager::complete(const Context& context,