Relay asserts to go

assert.go

@@ -0,0 +1,47 @@
+package imgui
+
+import "C"
+import (
+	"fmt"
+)
+
+// AssertHandler is a handler for an assertion that happened in the native part of ImGui.
+type AssertHandler func(expression string, file string, line int)
+
+// AssertionError is the standard error being thrown by the default handler.
+type AssertionError struct {
+	Expression string
+	File       string
+	Line       int
+}
+
+// Error returns the string representation.
+func (err AssertionError) Error() string {
+	return fmt.Sprintf(`Assertion failed!
+File: %s, Line %d
+
+Expression: %s
+`, err.File, err.Line, err.Expression)
+}
+
+var assertHandler AssertHandler = func(expression string, file string, line int) {
+	panic(AssertionError{
+		Expression: expression,
+		File:       file,
+		Line:       line,
+	})
+}
+
+// SetAssertHandler registers a handler function for all future assertions.
+// Setting nil will disable special handling.
+// The default handler panics.
+func SetAssertHandler(handler AssertHandler) {
+	assertHandler = handler
+}
+
+//export goImguiAssertHandler
+func goImguiAssertHandler(expression *C.char, file *C.char, line C.int) {
+	if assertHandler != nil {
+		assertHandler(C.GoString(expression), C.GoString(file), int(line))
+	}
+}

cimgui/imgui/imconfig.h

@@ -135,22 +135,13 @@ namespace ImGui
  *
  * cimgui-go: https://github.com/AllenDang/cimgui-go
  * From: templates/assert.h
- *
- * TODO:
- * - tbh we can return data about an error back to GO and let it panic from GO.
- * - figure out how to convert cond into an human-readable expression (like in default assert func)
  */
-#define IM_ASSERT(_EXPR)  GoFriendlyAssert(_EXPR, __FILE__, __LINE__)
-#include <stdio.h>
-#include <stdlib.h>
-static void GoFriendlyAssert(bool cond/*const char *expr*/, const char *file, int line) {
-        if (cond) {
-                return;
-        }
-
-        fprintf(stdout, "File: %s, Line: %d\n", file, line);
-
-        // Instead of throwing an exception, we're using exit(1) to terminate the program.
-        exit(1);
-}
-
+extern "C" void goImguiAssertHandler(char const *expression, char const *file, int line);
+#define IM_ASSERT(_EXPR)                                   \
+   do                                                      \
+   {                                                       \
+      if ((_EXPR) == 0)                                    \
+      {                                                    \
+         goImguiAssertHandler(#_EXPR, __FILE__, __LINE__); \
+      }                                                    \
+   } while (false)

templates/assert.h

@@ -4,22 +4,13 @@
  *
  * cimgui-go: https://github.com/AllenDang/cimgui-go
  * From: templates/assert.h
- *
- * TODO:
- * - tbh we can return data about an error back to GO and let it panic from GO.
- * - figure out how to convert cond into an human-readable expression (like in default assert func)
  */
-#define IM_ASSERT(_EXPR)  GoFriendlyAssert(_EXPR, __FILE__, __LINE__)
-#include <stdio.h>
-#include <stdlib.h>
-static void GoFriendlyAssert(bool cond/*const char *expr*/, const char *file, int line) {
-        if (cond) {
-                return;
-        }
-
-        fprintf(stdout, "File: %s, Line: %d\n", file, line);
-
-        // Instead of throwing an exception, we're using exit(1) to terminate the program.
-        exit(1);
-}
-
+extern "C" void goImguiAssertHandler(char const *expression, char const *file, int line);
+#define IM_ASSERT(_EXPR)                                   \
+   do                                                      \
+   {                                                       \
+      if ((_EXPR) == 0)                                    \
+      {                                                    \
+         goImguiAssertHandler(#_EXPR, __FILE__, __LINE__); \
+      }                                                    \
+   } while (false)