Fix Jupyter notebook import.

Author: kpeeters

client_server/CMakeLists.txt

@@ -30,6 +30,7 @@ set(CADABRA_SERVER_SRC
    Snoop.cc
    ${CADABRA_CORE_DIR}/InstallPrefix.cc
    ${CADABRA_CORE_DIR}/DataCell.cc
+   ${CADABRA_CORE_DIR}/Exceptions.cc
    ${CADABRA_CORE_DIR}/CdbPython.cc 
    ${CADABRA_CORE_DIR}/Stopwatch.cc 
    ${CADABRA_LIBS_DIR}/whereami/whereami.c
@@ -42,6 +43,7 @@ set(CADABRA_CLIENT_SRC
    Actions.cc 
    Snoop.cc 
    ${CADABRA_CORE_DIR}/DataCell.cc 
+   ${CADABRA_CORE_DIR}/Exceptions.cc 
    ${CADABRA_CORE_DIR}/InstallPrefix.cc
    ${CADABRA_LIBS_DIR}/whereami/whereami.c
    )

core/CMakeLists.txt

@@ -319,6 +319,7 @@ add_executable(cadabra2python
    CdbPython.cc
    InstallPrefix.cc    
    DataCell.cc
+   Exceptions.cc   
    ${CADABRA_LIBS_DIR}/whereami/whereami.c
    ${CADABRA_LIBS_DIR}/base64/base64.cc
    )
@@ -334,6 +335,7 @@ add_executable(cadabra2ipynb
    CdbPython.cc
    InstallPrefix.cc    
    DataCell.cc
+   Exceptions.cc   
    ${CADABRA_LIBS_DIR}/whereami/whereami.c
    ${CADABRA_LIBS_DIR}/base64/base64.cc
    )
@@ -348,6 +350,7 @@ add_executable(cadabra2cadabra
    cadabra2cadabra.cc 
    DataCell.cc 
    InstallPrefix.cc
+   Exceptions.cc
    ${CADABRA_LIBS_DIR}/whereami/whereami.c
    ${CADABRA_LIBS_DIR}/base64/base64.cc
    )

core/DataCell.cc

@@ -2,6 +2,7 @@
 #include "InstallPrefix.hh"
 #include "Config.hh"
 #include "DataCell.hh"
+#include "Exceptions.hh"
 #include <sstream>
 #include <fstream>
 #include <regex>
@@ -687,11 +688,11 @@ void cadabra::python_recurse(const DTree& doc, DTree::iterator it, std::ostrings
 
 nlohmann::json cadabra::ipynb2cnb(const nlohmann::json& root)
 	{
-	auto nbf = root["nbformat"];
+	int nbf = root.value("nbformat", 0);
 	nlohmann::json json;
 
-	if(!nbf)
-		return json;
+	if(nbf==0)
+		throw RuntimeException("Not a Jupyter notebook.");
 
 	json["description"]="Cadabra JSON notebook format";
 	json["version"]=1.0;

tests/ipynb_module.ipynb

@@ -0,0 +1,46 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {},
+   "outputs": [
+    {
+     "data": {
+      "text/markdown": [
+       "${}A_{m n p}$"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
+    }
+   ],
+   "source": [
+    "ex:=A_{m n p};"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Cadabra2",
+   "language": "python",
+   "name": "cadabra2"
+  },
+  "language_info": {
+   "codemirror_mode": "cadabra",
+   "file_extension": ".ipynb",
+   "mimetype": "text/cadabra",
+   "name": "cadabra2",
+   "pygments_lexer": "cadabra"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 4
+}

tests/modules.cdb

@@ -36,6 +36,14 @@ def test03():
 test03()
 
 
+from ipynb_module import ex as ex5
+
+def test04():
+    assert(ex5==$A_{m n p}$)
+    print("Test 04 passed")
+
+test04()
+
 
 # import module02
 #