check functions with narrower error message scope

matplotlibcpp.h

@@ -84,6 +84,18 @@ struct _interpreter {
         return ctx;
     }
 
+    PyObject* safe_import(PyObject* module, std::string fname) {
+        PyObject* fn = PyObject_GetAttrString(module, fname.c_str());
+
+        if (!fn)
+            throw std::runtime_error(std::string("Couldn't find required function: ") + fname);
+
+        if (!PyFunction_Check(fn))
+            throw std::runtime_error(fname + std::string(" is unexpectedly not a PyFunction."));
+
+        return fn;
+    }
+
 private:
 
 #ifndef WITHOUT_NUMPY
@@ -151,120 +163,45 @@ private:
         Py_DECREF(pylabname);
         if (!pylabmod) { throw std::runtime_error("Error loading module pylab!"); }
 
-        s_python_function_show = PyObject_GetAttrString(pymod, "show");
-        s_python_function_close = PyObject_GetAttrString(pymod, "close");
-        s_python_function_draw = PyObject_GetAttrString(pymod, "draw");
-        s_python_function_pause = PyObject_GetAttrString(pymod, "pause");
-        s_python_function_figure = PyObject_GetAttrString(pymod, "figure");
-        s_python_function_fignum_exists = PyObject_GetAttrString(pymod, "fignum_exists");
-        s_python_function_plot = PyObject_GetAttrString(pymod, "plot");
-        s_python_function_quiver = PyObject_GetAttrString(pymod, "quiver");
-        s_python_function_semilogx = PyObject_GetAttrString(pymod, "semilogx");
-        s_python_function_semilogy = PyObject_GetAttrString(pymod, "semilogy");
-        s_python_function_loglog = PyObject_GetAttrString(pymod, "loglog");
-        s_python_function_fill = PyObject_GetAttrString(pymod, "fill");
-        s_python_function_fill_between = PyObject_GetAttrString(pymod, "fill_between");
-        s_python_function_hist = PyObject_GetAttrString(pymod,"hist");
-        s_python_function_scatter = PyObject_GetAttrString(pymod,"scatter");
-        s_python_function_subplot = PyObject_GetAttrString(pymod, "subplot");
-        s_python_function_legend = PyObject_GetAttrString(pymod, "legend");
-        s_python_function_ylim = PyObject_GetAttrString(pymod, "ylim");
-        s_python_function_title = PyObject_GetAttrString(pymod, "title");
-        s_python_function_axis = PyObject_GetAttrString(pymod, "axis");
-        s_python_function_xlabel = PyObject_GetAttrString(pymod, "xlabel");
-        s_python_function_ylabel = PyObject_GetAttrString(pymod, "ylabel");
-        s_python_function_xticks = PyObject_GetAttrString(pymod, "xticks");
-        s_python_function_yticks = PyObject_GetAttrString(pymod, "yticks");
-        s_python_function_grid = PyObject_GetAttrString(pymod, "grid");
-        s_python_function_xlim = PyObject_GetAttrString(pymod, "xlim");
-        s_python_function_ion = PyObject_GetAttrString(pymod, "ion");
-        s_python_function_ginput = PyObject_GetAttrString(pymod, "ginput");
-        s_python_function_save = PyObject_GetAttrString(pylabmod, "savefig");
-        s_python_function_annotate = PyObject_GetAttrString(pymod,"annotate");
-        s_python_function_clf = PyObject_GetAttrString(pymod, "clf");
-        s_python_function_errorbar = PyObject_GetAttrString(pymod, "errorbar");
-        s_python_function_tight_layout = PyObject_GetAttrString(pymod, "tight_layout");
-        s_python_function_stem = PyObject_GetAttrString(pymod, "stem");
-        s_python_function_xkcd = PyObject_GetAttrString(pymod, "xkcd");
-        s_python_function_text = PyObject_GetAttrString(pymod, "text");
-        s_python_function_suptitle = PyObject_GetAttrString(pymod, "suptitle");
-        s_python_function_bar = PyObject_GetAttrString(pymod,"bar");
-        s_python_function_subplots_adjust = PyObject_GetAttrString(pymod,"subplots_adjust");
-
-        if(    !s_python_function_show
-            || !s_python_function_close
-            || !s_python_function_draw
-            || !s_python_function_pause
-            || !s_python_function_figure
-            || !s_python_function_fignum_exists
-            || !s_python_function_plot
-            || !s_python_function_quiver
-            || !s_python_function_semilogx
-            || !s_python_function_semilogy
-            || !s_python_function_loglog
-            || !s_python_function_fill
-            || !s_python_function_fill_between
-            || !s_python_function_subplot
-            || !s_python_function_legend
-            || !s_python_function_ylim
-            || !s_python_function_title
-            || !s_python_function_axis
-            || !s_python_function_xlabel
-            || !s_python_function_ylabel
-            || !s_python_function_grid
-            || !s_python_function_xlim
-            || !s_python_function_ion
-            || !s_python_function_ginput
-            || !s_python_function_save
-            || !s_python_function_clf
-            || !s_python_function_annotate
-            || !s_python_function_errorbar
-            || !s_python_function_errorbar
-            || !s_python_function_tight_layout
-            || !s_python_function_stem
-            || !s_python_function_xkcd
-            || !s_python_function_text
-            || !s_python_function_suptitle
-            || !s_python_function_bar
-            || !s_python_function_subplots_adjust
-        ) { throw std::runtime_error("Couldn't find required function!"); }
-
-        if (   !PyFunction_Check(s_python_function_show)
-            || !PyFunction_Check(s_python_function_close)
-            || !PyFunction_Check(s_python_function_draw)
-            || !PyFunction_Check(s_python_function_pause)
-            || !PyFunction_Check(s_python_function_figure)
-            || !PyFunction_Check(s_python_function_fignum_exists)
-            || !PyFunction_Check(s_python_function_plot)
-            || !PyFunction_Check(s_python_function_quiver)
-            || !PyFunction_Check(s_python_function_semilogx)
-            || !PyFunction_Check(s_python_function_semilogy)
-            || !PyFunction_Check(s_python_function_loglog)
-            || !PyFunction_Check(s_python_function_fill)
-            || !PyFunction_Check(s_python_function_fill_between)
-            || !PyFunction_Check(s_python_function_subplot)
-            || !PyFunction_Check(s_python_function_legend)
-            || !PyFunction_Check(s_python_function_annotate)
-            || !PyFunction_Check(s_python_function_ylim)
-            || !PyFunction_Check(s_python_function_title)
-            || !PyFunction_Check(s_python_function_axis)
-            || !PyFunction_Check(s_python_function_xlabel)
-            || !PyFunction_Check(s_python_function_ylabel)
-            || !PyFunction_Check(s_python_function_grid)
-            || !PyFunction_Check(s_python_function_xlim)
-            || !PyFunction_Check(s_python_function_ion)
-            || !PyFunction_Check(s_python_function_ginput)
-            || !PyFunction_Check(s_python_function_save)
-            || !PyFunction_Check(s_python_function_clf)
-            || !PyFunction_Check(s_python_function_tight_layout)
-            || !PyFunction_Check(s_python_function_errorbar)
-            || !PyFunction_Check(s_python_function_stem)
-            || !PyFunction_Check(s_python_function_xkcd)
-            || !PyFunction_Check(s_python_function_text)
-            || !PyFunction_Check(s_python_function_suptitle)
-            || !PyFunction_Check(s_python_function_bar)
-            || !PyFunction_Check(s_python_function_subplots_adjust)
-        ) { throw std::runtime_error("Python object is unexpectedly not a PyFunction."); }
+        s_python_function_show = safe_import(pymod, "show");
+        s_python_function_close = safe_import(pymod, "close");
+        s_python_function_draw = safe_import(pymod, "draw");
+        s_python_function_pause = safe_import(pymod, "pause");
+        s_python_function_figure = safe_import(pymod, "figure");
+        s_python_function_fignum_exists = safe_import(pymod, "fignum_exists");
+        s_python_function_plot = safe_import(pymod, "plot");
+        s_python_function_quiver = safe_import(pymod, "quiver");
+        s_python_function_semilogx = safe_import(pymod, "semilogx");
+        s_python_function_semilogy = safe_import(pymod, "semilogy");
+        s_python_function_loglog = safe_import(pymod, "loglog");
+        s_python_function_fill = safe_import(pymod, "fill");
+        s_python_function_fill_between = safe_import(pymod, "fill_between");
+        s_python_function_hist = safe_import(pymod,"hist");
+        s_python_function_scatter = safe_import(pymod,"scatter");
+        s_python_function_subplot = safe_import(pymod, "subplot");
+        s_python_function_legend = safe_import(pymod, "legend");
+        s_python_function_ylim = safe_import(pymod, "ylim");
+        s_python_function_title = safe_import(pymod, "title");
+        s_python_function_axis = safe_import(pymod, "axis");
+        s_python_function_xlabel = safe_import(pymod, "xlabel");
+        s_python_function_ylabel = safe_import(pymod, "ylabel");
+        s_python_function_xticks = safe_import(pymod, "xticks");
+        s_python_function_yticks = safe_import(pymod, "yticks");
+        s_python_function_grid = safe_import(pymod, "grid");
+        s_python_function_xlim = safe_import(pymod, "xlim");
+        s_python_function_ion = safe_import(pymod, "ion");
+        s_python_function_ginput = safe_import(pymod, "ginput");
+        s_python_function_save = safe_import(pylabmod, "savefig");
+        s_python_function_annotate = safe_import(pymod,"annotate");
+        s_python_function_clf = safe_import(pymod, "clf");
+        s_python_function_errorbar = safe_import(pymod, "errorbar");
+        s_python_function_tight_layout = safe_import(pymod, "tight_layout");
+        s_python_function_stem = safe_import(pymod, "stem");
+        s_python_function_xkcd = safe_import(pymod, "xkcd");
+        s_python_function_text = safe_import(pymod, "text");
+        s_python_function_suptitle = safe_import(pymod, "suptitle");
+        s_python_function_bar = safe_import(pymod,"bar");
+        s_python_function_subplots_adjust = safe_import(pymod,"subplots_adjust");
 
         s_python_empty_tuple = PyTuple_New(0);
     }