feat(library/explicit): support partial explicit

src/library/explicit.cpp

@@ -11,6 +11,7 @@ Author: Leonardo de Moura
 
 namespace lean {
 static name * g_explicit_name = nullptr;
+static name * g_partial_explicit_name = nullptr;
 static name * g_as_atomic_name = nullptr;
 static name * g_as_is_name    = nullptr;
 static name * g_consume_args_name = nullptr;
@@ -20,6 +21,11 @@ bool is_explicit(expr const & e) { return is_annotation(e, *g_explicit_name); }
 bool is_nested_explicit(expr const & e) { return is_nested_annotation(e, *g_explicit_name); }
 expr const & get_explicit_arg(expr const & e) { lean_assert(is_explicit(e)); return get_annotation_arg(e); }
 
+expr mk_partial_explicit(expr const & e) { return mk_annotation(*g_partial_explicit_name, e); }
+bool is_partial_explicit(expr const & e) { return is_annotation(e, *g_partial_explicit_name); }
+bool is_nested_partial_explicit(expr const & e) { return is_nested_annotation(e, *g_partial_explicit_name); }
+expr const & get_partial_explicit_arg(expr const & e) { lean_assert(is_partial_explicit(e)); return get_annotation_arg(e); }
+
 expr mk_as_is(expr const & e) { return mk_annotation(*g_as_is_name, e); }
 bool is_as_is(expr const & e) { return is_annotation(e, *g_as_is_name); }
 expr const & get_as_is_arg(expr const & e) { lean_assert(is_as_is(e)); return get_annotation_arg(e); }
@@ -33,7 +39,8 @@ bool is_consume_args(expr const & e) { return is_annotation(e, *g_consume_args_n
 expr const & get_consume_args_arg(expr const & e) { lean_assert(is_consume_args(e)); return get_annotation_arg(e); }
 
 void initialize_explicit() {
-    g_explicit_name     = new name("@");
+    g_explicit_name     = new name("@@");
+    g_partial_explicit_name     = new name("@");    
     g_as_atomic_name    = new name("as_atomic");
     g_as_is_name        = new name("as_is");
     g_consume_args_name = new name("!");
@@ -47,6 +54,7 @@ void initialize_explicit() {
 void finalize_explicit() {
     delete g_as_is_name;
     delete g_as_atomic_name;
+    delete g_partial_explicit_name;
     delete g_explicit_name;
     delete g_consume_args_name;
 }
@@ -62,9 +70,24 @@ static int get_explicit_arg(lua_State * L) {
     return push_expr(L, get_explicit_arg(to_expr(L, 1)));
 }
 
+static int mk_partial_explicit(lua_State * L) { return push_expr(L, mk_partial_explicit(to_expr(L, 1))); }
+static int is_partial_explicit(lua_State * L) { return push_boolean(L, is_partial_explicit(to_expr(L, 1))); }
+static void check_partial_explicit(lua_State * L, int idx) {
+    if (!is_partial_explicit(to_expr(L, idx)))
+        throw exception(sstream() << "arg #" << idx << " is not a '@'-expression");
+}
+static int get_partial_explicit_arg(lua_State * L) {
+    check_partial_explicit(L, 1);
+    return push_expr(L, get_partial_explicit_arg(to_expr(L, 1)));
+}
+
 void open_explicit(lua_State * L) {
     SET_GLOBAL_FUN(mk_explicit,      "mk_explicit");
     SET_GLOBAL_FUN(is_explicit,      "is_explicit");
     SET_GLOBAL_FUN(get_explicit_arg, "get_explicit_arg");
+
+    SET_GLOBAL_FUN(mk_partial_explicit,      "mk_partial_explicit");
+    SET_GLOBAL_FUN(is_partial_explicit,      "is_partial_explicit");
+    SET_GLOBAL_FUN(get_partial_explicit_arg, "get_partial_explicit_arg");
 }
 }

src/library/explicit.h

@@ -9,7 +9,7 @@ Author: Leonardo de Moura
 #include "kernel/expr.h"
 
 namespace lean {
-/** \brief Create an explicit expression '@ f'.
+/** \brief Create an explicit expression '@@ f'.
     This only affects the elaborator behavior.
 */
 expr mk_explicit(expr const & e);
@@ -22,6 +22,20 @@ bool is_nested_explicit(expr const & e);
 */
 expr const & get_explicit_arg(expr const & e);
 
+/** \brief Create an partial explicit expression '@ f'.
+    This only affects the elaborator behavior.
+*/
+expr mk_partial_explicit(expr const & e);
+/** \brief Return true iff \c e is a partial explicit expression. */
+bool is_partial_explicit(expr const & e);
+/** \brief See #is_nested_annotation */
+bool is_nested_partial_explicit(expr const & e);
+/** \brief Return the argument of a partial explicit expression.
+    \pre is_partial_explicit(e)
+*/
+expr const & get_partial_explicit_arg(expr const & e);
+
+
 /** \brief Create an explicit expression that is accepted as is
     by the elaborator.
 */