Fix non-zero arity functions followed by other functions

Temporarily skip any queued function code characters when reading
the current function's arguments.

Fixes #2357.

src/input.cpp

@@ -42,6 +42,7 @@
 #include "output.h"
 #include <vector>
 #include <algorithm>
+#include <deque>
 
 #define DEFAULT_TERM L"ansi"
 #define MAX_INPUT_FUNCTION_ARGS 20
@@ -537,10 +538,23 @@ wchar_t input_function_pop_arg()
 void input_function_push_args(int code)
 {
     int arity = input_function_arity(code);
+    std::deque<wchar_t> skipped;
+
     for (int i = 0; i < arity; i++)
     {
-        input_function_push_arg(input_common_readch(0));
+        wchar_t arg;
+
+        // skip and queue up any function codes
+        while(((arg = input_common_readch(0)) >= R_MIN) && (arg <= R_MAX))
+        {
+            skipped.push_front(arg);
         }
+
+        input_function_push_arg(arg);
+    }
+
+    // push the function codes back into the input stream
+    std::for_each(skipped.begin(), skipped.end(), input_common_next_ch);
 }
 
 /**