feat(frontends/lean/info_manager): add separator -- when displaying PROOF_STATE info

This feature was implemented to address issue #259

src/frontends/lean/info_manager.cpp

@@ -267,7 +267,15 @@ public:
     virtual bool is_cheap() const { return false; }
     virtual void display(io_state_stream const & ios, unsigned line) const {
         ios << "-- PROOF_STATE|" << line << "|" << get_column() << "\n";
-        ios << m_ps << endl;
+        bool first = true;
+        substitution s = m_ps.get_subst();
+        for (goal const & g : m_ps.get_goals()) {
+            if (first)
+                first = false;
+            else
+                ios << "--" << endl;
+            ios << g.instantiate(s) << endl;
+        }
         ios << "-- ACK" << endl;
     }
 };

src/library/tactic/goal.cpp

@@ -78,6 +78,11 @@ expr goal::mk_meta(name const & n, expr const & type) const {
     return copy_tag(m_meta, mk_app(mvar, locals));
 }
 
+goal goal::instantiate(substitution const & s) const {
+    substitution s1(s);
+    return goal(s1.instantiate_all(m_meta), s1.instantiate_all(m_type));
+}
+
 static bool validate_locals(expr const & r, unsigned num_locals, expr const * locals) {
     bool failed = false;
     for_each(r, [&](expr const & e, unsigned) {
@@ -122,6 +127,12 @@ list<expr> goal::to_context() const {
     return to_list(locals.begin(), locals.end());
 }
 
+io_state_stream const & operator<<(io_state_stream const & out, goal const & g) {
+    options const & opts = out.get_options();
+    out.get_stream() << mk_pair(g.pp(out.get_formatter()), opts);
+    return out;
+}
+
 DECL_UDATA(goal)
 
 static int mk_goal(lua_State * L) { return push_goal(L, goal(to_expr(L, 1), to_expr(L, 2))); }

src/library/tactic/goal.h

@@ -71,6 +71,9 @@ public:
     */
     list<expr> to_context() const;
 
+    /** \brief Apply given substitution to goal */
+    goal instantiate(substitution const & s) const;
+
     format pp(formatter const & fmt, substitution const & s) const;
     format pp(formatter const & fmt) const;
 };

tests/lean/interactive/proof_state_info2.input.expected.out

@@ -24,6 +24,7 @@ c : Prop,
 Ha : a,
 Hb : b
 ⊢ a
+--
 a : Prop,
 b : Prop,
 c : Prop,