Sorting completion candidates based on clang priority

irony-completion.el

@@ -200,7 +200,10 @@ displayed when a derived class overrides virtual methods."
             (cl-case style
               (case-insensitive "case-insensitive")
               (smart-case "smart-case")
-              (t "exact"))))
+              (t "exact"))
+            (cl-case irony-candidates-clang-sorting
+              (alphabetical "alphabetical")
+              (t "alphabetical-clang"))))
   :update irony--server-query-update)
 
 (defun irony--candidates-task (&optional buffer pos prefix style)

irony.el

@@ -180,6 +180,17 @@ Larger values can improve performances on large buffers.
 If non-nil, `w32-pipe-buffer-size' will be let-bound to this value
 during the creation of the irony-server process.")
 
+(defcustom irony-candidates-clang-sorting nil
+  "Determine the sorting strategy for completion candidates list
+
+If set to nil, clang priority will be used on top of alphabetical sorting when completing to propose context-aware and more-likely completions.
+
+If set to `alphabetical', clang priority will be ignored and candidates will be sorted alphabetically only."
+  :type '(choice
+          (const :tag "Alphabetical + clang priority" nil)
+          (const :tag "Alphabetical only" alphabetical)))
+
+
 
 ;;
 ;; Public/API variables

server/src/Command.cpp

@@ -221,6 +221,7 @@ Command *CommandParser::parse(const std::vector<std::string> &argv) {
   case Command::Candidates:
     positionalArgs.push_back(StringConverter(&command_.prefix));
     positionalArgs.push_back(PrefixMatchStyleConverter(&command_.style));
+    positionalArgs.push_back(StringConverter(&command_.sorting));
     break;
   case Command::CompletionDiagnostics:
   case Command::Diagnostics:

server/src/Command.h

@@ -50,6 +50,7 @@ struct Command {
   std::string unsavedFile;
   std::string dir;
   std::string prefix;
+  std::string sorting;
   PrefixMatchStyle style;
   unsigned line;
   unsigned column;

server/src/Irony.cpp

@@ -19,9 +19,23 @@
 #include <iostream>
 #include <fstream>
 #include <cctype>
+#include <sstream>
+#include <vector>
 
 namespace {
 
+struct CompletionCandidate
+{
+  unsigned int priority;
+  std::string str;
+
+  CompletionCandidate(unsigned int priority, const std::string& str) : priority(priority), str(str) {}
+
+  bool operator < (const CompletionCandidate& candidate) const {
+    return (priority < candidate.priority);
+  }
+};
+
 std::string cxStringToStd(CXString cxString) {
   std::string stdStr;
 
@@ -359,7 +373,7 @@ void Irony::completionDiagnostics() const {
   std::cout << ")\n";
 }
 
-void Irony::candidates(const std::string &prefix, PrefixMatchStyle style) const {
+void Irony::candidates(const std::string &prefix, PrefixMatchStyle style, const std::string &sorting) const {
   if (activeCompletionResults_ == nullptr) {
     std::cout << "nil\n";
     return;
@@ -375,6 +389,7 @@ void Irony::candidates(const std::string &prefix, PrefixMatchStyle style) const
   std::string typedtext, brief, resultType, prototype, postCompCar, available;
 
   std::vector<unsigned> postCompCdr;
+  std::vector<CompletionCandidate> candidates;
 
   for (unsigned i = 0; i < completions->NumResults; ++i) {
     CXCompletionResult candidate = completions->Results[i];
@@ -508,19 +523,35 @@ void Irony::candidates(const std::string &prefix, PrefixMatchStyle style) const
         clang_getCompletionBriefComment(candidate.CompletionString));
 #endif
 
+    std::stringstream candidateSS;
+
     // see irony-completion.el#irony-completion-candidates
-    std::cout << '(' << support::quoted(typedtext)
-              << ' ' << priority
-              << ' ' << support::quoted(resultType)
-              << ' ' << support::quoted(brief)
-              << ' ' << support::quoted(prototype)
-              << ' ' << annotationStart
-              << " (" << support::quoted(postCompCar);
+    candidateSS << '(' << support::quoted(typedtext)
+                << ' ' << priority
+                << ' ' << support::quoted(resultType)
+                << ' ' << support::quoted(brief)
+                << ' ' << support::quoted(prototype)
+                << ' ' << annotationStart
+                << " (" << support::quoted(postCompCar);
     for (unsigned index : postCompCdr)
-      std::cout << ' ' << index;
-    std::cout << ")"
-              << ' ' << available
-              << ")\n";
+      candidateSS << ' ' << index;
+    candidateSS << ")"
+                << ' ' << available
+                << ")\n";
+
+    // Add candidate to candidate list
+    candidates.push_back(CompletionCandidate(priority, candidateSS.str()));
+  }
+
+  if (sorting == "alphabetical-clang") {
+    // Sort candidates list
+    // ASC - Smaller values indicate higher-priority (more likely) completions.
+    std::sort(candidates.begin(), candidates.end());
+  }
+
+  // Output sorted list
+  for (auto &candidate : candidates) {
+    std::cout << candidate.str;
   }
 
   std::cout << ")\n";

server/src/Irony.h

@@ -102,7 +102,7 @@ class Irony {
   /// Get all the completion candidates.
   ///
   /// \pre complete() was called.
-  void candidates(const std::string &prefix, PrefixMatchStyle style) const;
+  void candidates(const std::string &prefix, PrefixMatchStyle style, const std::string &sorting) const;
 
   /// Get the diagnostics produced by the last \c complete().
   ///

server/src/main.cpp

@@ -181,7 +181,7 @@ int main(int ac, const char *av[]) {
       break;
 
     case Command::Candidates:
-      irony.candidates(c->prefix, c->style);
+      irony.candidates(c->prefix, c->style, c->sorting);
       break;
 
     case Command::CompletionDiagnostics: