1 files changed, 42 insertions, 5 deletions

diff --git a/forth.c b/forth.c
index e44d372..c70cc83 100644
--- a/forth.c
+++ b/forth.c
@@ -8,16 +8,42 @@
 #include "stack.h"
 #include "forthmachine.h"
 
+int exitcode = EXIT_SUCCESS;
+
+// Only used when in buffer_eval mode.
 int initialised = false;
+// Only used when in buffer_eval mode.
 forthmachine* fm;
-int lastline = 0;
+
+// Pointer to errormessage.
+// Only used when in buffer_eval mode.
+char* errormessage;
+
+void buffer_eval_handleerror(char* err) {
+    exitcode = EXIT_FAILURE;
+    // Set errormessage global
+    errormessage = malloc(sizeof(char) * MAX_OUTPUT_BUFFER_SIZE);
+    strcpy(errormessage, err);
+    #ifdef __EMSCRIPTEN__
+    initialised = false;
+    free(fm);
+    fm = NULL;
+    strcat(errormessage, "\nEnvironment has been reset.\n");
+    #endif
+}
+
+
 char* buffer_eval(int len, char* line) {
     if (!initialised) {
-        fm = forthmachine_new();
+        // initialise global forthmachine instance on first call
+        fm = forthmachine_new(buffer_eval_handleerror);
         initialised = true;
     }
     strcpy(fm->outputbuffer, "");
     forthmachine_eval(fm, len, line);
+    if (exitcode == EXIT_FAILURE) {
+        return errormessage;
+    }
     if (fm->outputbuffer && strlen(fm->outputbuffer)) {
         return fm->outputbuffer;
     } else {
@@ -25,8 +51,14 @@ char* buffer_eval(int len, char* line) {
     }
 }
 
+void error_print(char* error) {
+    exitcode = exitcode || EXIT_FAILURE;
+    fprintf(stderr, "%s\n", error);
+    exit(exitcode);
+}
+
 void stdin_eval() {
-    forthmachine* fm = forthmachine_new();
+    forthmachine* fm = forthmachine_new(error_print);
     char *line = NULL;
     size_t len = 0;
     ssize_t read;
@@ -40,8 +72,12 @@ void stdin_eval() {
 #ifndef __EMSCRIPTEN__
 
 int main(int argc, char** argv) {
-    if (argc>1) printf("%s", buffer_eval(strlen(argv[1])+1, argv[1]));
-    else stdin_eval();
+    if (argc>1) {
+        printf("%s", buffer_eval(strlen(argv[1])+1, argv[1]));
+    } else {
+        stdin_eval();
+    }
+    return exitcode;
 }
 
 #else
@@ -50,6 +86,7 @@ int main(int argc, char** argv) {
 #define EXTERN
 
 EXTERN EMSCRIPTEN_KEEPALIVE char* extern_eval(char* line) {
+    exitcode = EXIT_SUCCESS;
     return buffer_eval(strlen(line)+1, line);
 }
 #endif