Added message handling for qalc function

qalculator.cpp

@@ -1,26 +1,50 @@
 #include <lua.hpp>
 #include <libqalculate/qalculate.h>
+#include <vector>
 #include <string>
 
 EvaluationOptions user_evaluation_options = default_evaluation_options;
 
-const char* qalculate(const char* input, bool exact_mode) {
+struct Output_struct {
+    char * result;
+    std::vector<char *> messages;
+};
+
+Output_struct qalculate(const char* input, bool exact_mode, bool interval_mode) {
+    // Create and prepare calculator
     Calculator* c = new Calculator();
     c->loadExchangeRates();
     c->loadGlobalDefinitions();
     c->loadLocalDefinitions();
+    // Create input and output string buffers
     std::string Input = input;
     std::string Output;
-    if (exact_mode) {
-        user_evaluation_options.approximation = APPROXIMATION_EXACT;
-    } else {
-        user_evaluation_options.approximation = APPROXIMATION_APPROXIMATE;
-    }
+    // Check evaluation options
+    user_evaluation_options.interval_calculation = (interval_mode ?
+        INTERVAL_CALCULATION_NONE :
+        INTERVAL_CALCULATION_VARIANCE_FORMULA);
+    user_evaluation_options.approximation = (exact_mode ? 
+        APPROXIMATION_EXACT :
+        APPROXIMATION_APPROXIMATE);
+    // Prepare output struct
+    struct Output_struct output;
+    memset(&output,0,sizeof(Output_struct));
+    // Evaluate and record result in Output
     Output = c->calculateAndPrint(Input,2000,user_evaluation_options);
+    // record messages
+    std::string current_msg;
+    while (c->message() != NULL) {
+        current_msg = c->message()->message();
+        output.messages.push_back(new char[current_msg.size()+1]);
+        current_msg.copy(output.messages.back(),current_msg.size());
+        output.messages.back()[current_msg.size()] = "\0"[0];
+        c->nextMessage();
+    }
     delete c;
-    char * output = new char [Output.length()+1];
-    Output.copy(output,Output.length());
-    output[Output.length()] = "\0"[0];
+    // Copy result to the output structure
+    output.result = new char [Output.length()+1];
+    Output.copy(output.result,Output.length());
+    output.result[Output.length()] = "\0"[0];
     return output;
 }
 
@@ -28,9 +52,15 @@ extern "C"
 int l_qalc(lua_State* L) {
     const char * input = luaL_checkstring(L, 1);
     bool exact_mode = lua_toboolean(L, 2);
-    const char * output = qalculate(input, exact_mode);
-    lua_pushstring(L, output);
-    return 1;
+    bool interval_mode = lua_toboolean(L, 3);
+    Output_struct output = qalculate(input, exact_mode, !interval_mode);
+    lua_pushstring(L, output.result);
+    lua_newtable(L);
+    for (int i = 0; i < output.messages.size(); i++) {
+        lua_pushstring(L, output.messages[i]);
+        lua_rawseti(L, -2, i+1);
+    }
+    return 2;
 }
 
 extern "C"

test.lua

@@ -1,3 +1,7 @@
 qalculate = require("libqalculator")
-print(qalculate.qalc("sin(3 rad)"))
-print(qalculate.qalc("sin(3 rad)",true))
+local result,messages = qalculate.qalc("sin(3 rad)")
+print(result,table.concat(messages))
+local result,messages = qalculate.qalc("fibonacci()")
+print(result,table.concat(messages))
+local result,messages = qalculate.qalc("sin(3 rad)",true)
+print(result,table.concat(messages))