Print call stack if an error occurs in a user-defined function.

src/files.c

@@ -163,6 +163,7 @@ int ReadLine(void)
 	LineNo = CLine->LineNo;
 	CLine = CLine->next;
 	FreshLine = 1;
+        clear_callstack();
 	if (DebugFlag & DB_ECHO_LINE) OutputLine(ErrFp);
 	return OK;
     }
@@ -263,6 +264,7 @@ static int ReadLineFromFile(int use_pclose)
 	}
 
 	FreshLine = 1;
+        clear_callstack();
 	if (DebugFlag & DB_ECHO_LINE) OutputLine(ErrFp);
 	return OK;
     }
@@ -818,6 +820,7 @@ static int IncludeCmd(char const *cmd)
     int old_flag;
 
     FreshLine = 1;
+    clear_callstack();
     if (IStackPtr+1 >= INCLUDE_NEST) return E_NESTED_INCLUDE;
     i = &IStack[IStackPtr];
 
@@ -935,6 +938,7 @@ int IncludeFile(char const *fname)
     struct stat statbuf;
 
     FreshLine = 1;
+    clear_callstack();
     if (IStackPtr+1 >= INCLUDE_NEST) return E_NESTED_INCLUDE;
     i = &IStack[IStackPtr];
 

src/main.c

@@ -605,12 +605,16 @@ void Eprint(char const *fmt, ...)
 
     if (FreshLine && FileName) {
 	FreshLine = 0;
-	if (strcmp(FileName, "-"))
+	if (strcmp(FileName, "-")) {
+            print_callstack(ErrFp);
 	    (void) fprintf(ErrFp, "%s(%d): ", FileName, LineNo);
-	else
+        } else {
+            print_callstack(ErrFp);
 	    (void) fprintf(ErrFp, "-stdin-(%d): ", LineNo);
+        }
 	if (DebugFlag & DB_PRTLINE) OutputLine(ErrFp);
     } else if (FileName) {
+        print_callstack(ErrFp);
 	fprintf(ErrFp, "       ");
     }
 

src/protos.h

@@ -175,4 +175,4 @@ int push_call(char const *filename, char const *func, int lineno);
 void clear_callstack(void);
 int have_callstack(void);
 int print_callstack(FILE *fp);
-
+void pop_call(void);

src/userfns.c

@@ -316,7 +316,11 @@ int CallUserFunc(char const *name, int nargs, ParsePtr p)
     /* Skip the opening bracket, if there's one */
     while (isempty(*s)) s++;
     if (*s == BEG_OF_EXPR) s++;
+    push_call(f->filename, f->name, f->lineno);
     h = Evaluate(&s, f->locals, p);
+    if (h == OK) {
+        pop_call();
+    }
     f->IsActive = 0;
     DestroyLocalVals(f);
     if (DebugFlag &DB_PRTEXPR) {

src/utils.c

@@ -237,9 +237,18 @@ print_callstack(FILE *fp)
     int done = 0;
     cs *entry = callstack;
     while(entry) {
-        (void) fprintf(fp, "%s(%d): %s\n", entry->filename, entry->lineno, entry->func);
+        (void) fprintf(fp, "%s(%d): In function `%s'\n", entry->filename, entry->lineno, entry->func);
         done = 1;
         entry = entry->next;
     }
     return done;
 }
+void
+pop_call(void)
+{
+    cs *entry = callstack;
+    if (entry) {
+        callstack = entry->next;
+        destroy_cs(entry);
+    }
+}