feat(kernel): add mk_hott_environment function for creating HoTT compatible environments

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

src/CMakeLists.txt

@@ -217,6 +217,8 @@ add_subdirectory(kernel/inductive)
 set(LEAN_LIBS ${LEAN_LIBS} inductive)
 add_subdirectory(kernel/standard)
 set(LEAN_LIBS ${LEAN_LIBS} standard_kernel)
+add_subdirectory(kernel/hott)
+set(LEAN_LIBS ${LEAN_LIBS} hott_kernel)
 add_subdirectory(library)
 set(LEAN_LIBS ${LEAN_LIBS} library)
 # add_subdirectory(library/rewriter)

src/kernel/hott/CMakeLists.txt

@@ -0,0 +1,2 @@
+add_library(hott_kernel hott.cpp)
+target_link_libraries(hott_kernel ${LEAN_LIBS})

src/kernel/hott/hott.cpp

@@ -0,0 +1,22 @@
+/*
+Copyright (c) 2014 Microsoft Corporation. All rights reserved.
+Released under Apache 2.0 license as described in the file LICENSE.
+
+Author: Leonardo de Moura
+*/
+#include "kernel/inductive/inductive.h"
+
+namespace lean {
+using inductive::inductive_normalizer_extension;
+
+/** \brief Create a HoTT (Homotopy Type Theory) compatible environment */
+environment mk_hott_environment(unsigned trust_lvl) {
+    return environment(trust_lvl,
+                       false /* Type.{0} is proof relevant */,
+                       true  /* Eta */,
+                       false /* Type.{0} is predicative */,
+                       list<name>(name("Id")) /* Exact equality types are proof irrelevant */,
+                       /* builtin support for inductive datatypes */
+                       std::unique_ptr<normalizer_extension>(new inductive_normalizer_extension()));
+}
+}

src/kernel/hott/hott.h

@@ -0,0 +1,11 @@
+/*
+Copyright (c) 2014 Microsoft Corporation. All rights reserved.
+Released under Apache 2.0 license as described in the file LICENSE.
+
+Author: Leonardo de Moura
+*/
+#pragma once
+#include "kernel/environment.h"
+namespace lean {
+environment mk_hott_environment(unsigned trust_lvl = 0);
+}