simple c-style interface to facilitate integration with js when using…

… emscripten

Task #153 - provide hooks for calling yacas from js when compiled with emscripten

CMakeLists.txt

@@ -22,14 +22,14 @@ endif ()
 
 
 if (${CMAKE_CXX_COMPILER_ID} STREQUAL "GNU" OR ${CMAKE_CXX_COMPILER_ID} STREQUAL "Clang")
-    set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -pedantic -Wall -std=c++11")
+   set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -pedantic -Wall -std=c++11")
 elseif (${CMAKE_CXX_COMPILER_ID} STREQUAL "MSVC")
     set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /wd4800")
     add_definitions(-DYACAS_NO_CONSTEXPR -DYACAS_NO_ATOMIC_TYPES -DYACAS_UINT32_T_IN_GLOBAL_NAMESPACE)
 endif ()
 
 if (${CMAKE_SYSTEM_NAME} STREQUAL "Emscripten")
-    set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -s DISABLE_EXCEPTION_CATCHING=0")
+    set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -s DISABLE_EXCEPTION_CATCHING=0 -s ASSERTIONS=1")
     set (CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} --embed-file ${PROJECT_SOURCE_DIR}/scripts@/share/yacas/scripts")
 endif ()
 
@@ -121,6 +121,8 @@ set (YACAS_WIN32_SOURCES src/win32commandline.cpp res/yacas.rc)
 set (YACAS_UNIX_HEADERS include/yacas/unixcommandline.h)
 set (YACAS_WIN32_HEADERS include/yacas/win32commandline.h)
 
+set (YACAS_JS_INTERFACE_SOURCES src/js_interface.cpp)
+
 if (UNIX)
   set (YACAS_SOURCES ${YACAS_COMMON_SOURCES} ${YACAS_UNIX_SOURCES})
   set (YACAS_HEADERS ${YACAS_UNIX_HEADERS})
@@ -129,6 +131,10 @@ else ()
   set (YACAS_HEADERS ${YACAS_WIN32_HEADERS})
 endif ()
 
+if (${CMAKE_SYSTEM_NAME} STREQUAL "Emscripten")
+  set (YACAS_SOURCES ${YACAS_SOURCES} ${YACAS_JS_INTERFACE_SOURCES})
+endif ()
+
 set (YACAS_SCRIPTS 
     scripts/array.rep/code.ys
     scripts/array.rep/code.ys.def

src/js_interface.cpp

@@ -0,0 +1,89 @@
+/*
+ * This file is part of yacas.
+ * Yacas is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesset General Public License as
+ * published by the Free Software Foundation, either version 2.1
+ * of the License, or (at your option) any later version.
+ *
+ * Yacas is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with yacas.  If not, see <http://www.gnu.org/licenses/>.
+ * 
+ */
+
+/* 
+ * File:   js_interface.cpp
+ * Author: mazur
+ *
+ * Created on January 19, 2016, 10:34 AM
+ */
+
+#include <emscripten.h>
+
+#include <string>
+
+#include "yacas/yacas.h"
+
+namespace {
+    static CYacas* _yacas;
+    static std::string _yacas_result;
+    static std::string _yacas_side_effects;
+    static bool _yacas_is_error;
+}
+
+extern "C" bool EMSCRIPTEN_KEEPALIVE yacas_is_error()
+{
+    return _yacas_is_error;
+}
+
+extern "C" char* EMSCRIPTEN_KEEPALIVE yacas_result()
+{
+    std::size_t rn = _yacas_result.length();
+    char* r = new char[rn + 1];
+    for (std::size_t i = 0; i < rn; ++i)
+        r[i] = _yacas_result[i];
+
+    r[rn] = 0;
+
+    return r;
+}
+
+extern "C" char* EMSCRIPTEN_KEEPALIVE yacas_side_effects()
+{
+    std::size_t rn = _yacas_side_effects.length();
+    char* r = new char[rn + 1];
+    for (std::size_t i = 0; i < rn; ++i)
+        r[i] = _yacas_side_effects[i];
+
+    r[rn] = 0;
+
+    return r;
+}
+
+extern "C" void EMSCRIPTEN_KEEPALIVE yacas_evaluate(const char* const p)
+{
+    static std::stringstream os;
+    os.clear();
+    os.str("");
+
+    if (!_yacas) {
+        _yacas = new CYacas(os);
+        _yacas->Evaluate("DefaultDirectory(\"/share/yacas/scripts/\");");
+        _yacas->Evaluate("Load(\"yacasinit.ys\");");
+    }
+
+    _yacas->Evaluate(p);
+
+    _yacas_is_error = _yacas->IsError();
+
+    if (!_yacas_is_error)
+        _yacas_result = _yacas->Result();
+    else
+        _yacas_result = _yacas->Error();
+
+    _yacas_side_effects = os.str();
+}