Improve formatter usage. Fix bug in object printer.

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

src/exprlib/formatter.cpp

@@ -9,7 +9,7 @@ Author: Leonardo de Moura
 #include "printer.h"
 
 namespace lean {
-class simple_formatter : public formatter {
+class simple_formatter_cell : public formatter_cell {
 public:
     virtual format operator()(expr const & e) {
         std::ostringstream s; s << e; return format(s.str());
@@ -31,7 +31,7 @@ public:
         std::ostringstream s; s << env; return format(s.str());
     }
 };
-std::shared_ptr<formatter> mk_simple_formatter() {
-    return std::shared_ptr<formatter>(new simple_formatter());
+formatter mk_simple_formatter() {
+    return formatter(new simple_formatter_cell());
 }
 }

src/exprlib/formatter.h

@@ -14,9 +14,9 @@ class object;
 /**
    \brief API for formatting expressions, contexts and environments.
 */
-class formatter {
+class formatter_cell {
 public:
-    virtual ~formatter() {}
+    virtual ~formatter_cell() {}
     /** \brief Format the given expression. */
     virtual format operator()(expr const & e) = 0;
     /** \brief Format the given context. */
@@ -34,8 +34,18 @@ public:
     /** \brief Format the given environment */
     virtual format operator()(environment const & env) = 0;
 };
-/**
-   \brief Return simple expression formatter that just uses printer module.
-*/
-std::shared_ptr<formatter> mk_simple_formatter();
+
+class formatter {
+    std::shared_ptr<formatter_cell> m_cell;
+public:
+    formatter(formatter_cell * c):m_cell(c) {}
+    formatter(std::shared_ptr<formatter_cell> const & c):m_cell(c) {}
+    format operator()(expr const & e) { return (*m_cell)(e); }
+    format operator()(context const & c) { return (*m_cell)(c); }
+    format operator()(context const & c, expr const & e, bool format_ctx = false) { return (*m_cell)(c, e, format_ctx); }
+    format operator()(object const & obj) { return (*m_cell)(obj); }
+    format operator()(environment const & env) { return (*m_cell)(env); }
+};
+
+formatter mk_simple_formatter();
 }

src/exprlib/printer.cpp

@@ -163,6 +163,7 @@ std::ostream & operator<<(std::ostream & out, object const & obj) {
     case object_kind::Neutral:
         break;
     }
+    return out;
 }
 
 std::ostream & operator<<(std::ostream & out, environment const & env) {

src/frontend/pp.cpp

@@ -573,7 +573,7 @@ public:
     }
 };
 
-class pp_formatter : public formatter {
+class pp_formatter_cell : public formatter_cell {
     frontend const & m_frontend;
     options          m_options;
     unsigned         m_indent;
@@ -652,13 +652,13 @@ class pp_formatter : public formatter {
     }
 
 public:
-    pp_formatter(frontend const & fe, options const & opts):
+    pp_formatter_cell(frontend const & fe, options const & opts):
         m_frontend(fe),
         m_options(opts) {
         m_indent = get_pp_indent(opts);
     }
 
-    virtual ~pp_formatter() {
+    virtual ~pp_formatter_cell() {
     }
 
     virtual format operator()(expr const & e) {
@@ -714,13 +714,13 @@ public:
     }
 };
 
-std::shared_ptr<formatter> mk_pp_formatter(frontend const & fe, options const & opts) {
-    return std::shared_ptr<formatter>(new pp_formatter(fe, opts));
+formatter mk_pp_formatter(frontend const & fe, options const & opts) {
+    return formatter(new pp_formatter_cell(fe, opts));
 }
 
 std::ostream & operator<<(std::ostream & out, frontend const & fe) {
-    auto pp = mk_pp_formatter(fe, options());
-    out << (*pp)(fe.get_environment());
+    formatter fmt = mk_pp_formatter(fe, options());
+    out << fmt(fe.get_environment());
     return out;
 }
 }

src/frontend/pp.h

@@ -11,6 +11,6 @@ Author: Leonardo de Moura
 
 namespace lean {
 class frontend;
-std::shared_ptr<formatter> mk_pp_formatter(frontend const & fe, options const & opts = options());
+formatter mk_pp_formatter(frontend const & fe, options const & opts = options());
 std::ostream & operator<<(std::ostream & out, frontend const & fe);
 }

src/kernel/environment.h

@@ -134,6 +134,7 @@ public:
         bool operator==(object_iterator const & s) const { lean_assert(&m_env == &(s.m_env)); return m_idx == s.m_idx; }
         bool operator!=(object_iterator const & s) const { return !operator==(s); }
         object const & operator*() { return m_env.get_object(m_idx, m_local); }
+        object const * operator->() { return &(m_env.get_object(m_idx, m_local)); }
     };
 
     /**

src/tests/frontend/frontend.cpp

@@ -56,8 +56,7 @@ static void tst3() {
 
 static void tst4() {
     frontend f;
-    std::shared_ptr<formatter> fmt_ptr = mk_pp_formatter(f);
-    formatter & fmt = *fmt_ptr;
+    formatter fmt = mk_pp_formatter(f);
     expr Bool = Const("Bool");
     context c;
     c = extend(c, "x", Bool);
@@ -72,8 +71,7 @@ static void tst4() {
 static void tst5() {
     std::cout << "=================\n";
     frontend f;
-    std::shared_ptr<formatter> fmt_ptr = mk_pp_formatter(f);
-    formatter & fmt = *fmt_ptr;
+    formatter fmt = mk_pp_formatter(f);
     f.add_var("A", Type());
     f.add_var("x", Const("A"));
     object const & obj = f.find_object("x");
@@ -103,8 +101,7 @@ static void tst6() {
     frontend f;
     environment env;
     env.add_neutral_object(new alien_cell());
-    std::shared_ptr<formatter> fmt_ptr = mk_pp_formatter(f);
-    formatter & fmt = *fmt_ptr;
+    formatter fmt = mk_pp_formatter(f);
     std::cout << fmt(env) << "\n";
 }
 

src/tests/kernel/level.cpp

@@ -11,6 +11,20 @@ Author: Leonardo de Moura
 #include "test.h"
 using namespace lean;
 
+static void tst0() {
+    environment env;
+    lean_assert(env.begin_objects() == env.end_objects());
+    std::for_each(env.begin_objects(), env.end_objects(), [&](object const & obj) {
+            std::cout << obj.keyword() << "\n";
+        });
+    level l1 = env.add_uvar(name(name("l1"), "suffix"), level());
+    lean_assert(env.begin_objects() != env.end_objects());
+    std::for_each(env.begin_objects(), env.end_objects(), [&](object const & obj) {
+            std::cout << obj.keyword() << "\n";
+        });
+    std::cout << env;
+}
+
 static void tst1() {
     environment env;
     level l1 = env.add_uvar(name(name("l1"), "suffix"), level());
@@ -94,6 +108,7 @@ static void tst5() {
 }
 
 int main() {
+    tst0();
     tst1();
     tst2();
     tst3();