feat(frontends/lean/server): add CLEAR_CACHE command, closes #100

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>

src/frontends/lean/server.cpp

@@ -97,6 +97,7 @@ static std::string g_info("INFO");
 static std::string g_set("SET");
 static std::string g_eval("EVAL");
 static std::string g_wait("WAIT");
+static std::string g_clear_cache("CLEAR_CACHE");
 
 static bool is_command(std::string const & cmd, std::string const & line) {
     return line.compare(0, cmd.size(), cmd) == 0;
@@ -319,6 +320,8 @@ bool server::operator()(std::istream & in) {
             } else if (is_command(g_eval, line)) {
                 read_line(in, line);
                 eval(line);
+            } else if (is_command(g_clear_cache, line)) {
+                m_cache.clear();
             } else if (is_command(g_wait, line)) {
                 if (m_thread_ptr) {
                     m_thread_ptr->join();

src/library/definition_cache.cpp

@@ -150,6 +150,11 @@ void definition_cache::erase(name const & n) {
     m_definitions.erase(n);
 }
 
+void definition_cache::clear() {
+    lock_guard<mutex> lc(m_mutex);
+    m_definitions.clear();
+}
+
 optional<std::tuple<level_param_names, expr, expr>> definition_cache::find(name const & n, expr const & pre_type, expr const & pre_value) {
     entry const * it;
     {

src/library/definition_cache.h

@@ -36,5 +36,7 @@ public:
     void load(std::istream & in);
     /** \brief Remove the entry named \c n from the cache. */
     void erase(name const & n);
+    /** \brief Clear the whole cache */
+    void clear();
 };
 }