public void checkcontext(Symtab st) {
		SymtabEntry ste = st.lookup(name);
		if (ste == null)
			Main.error("invalid variable (" + name + ")");
		if (ste.getScope() != null)
			if (!ste.getScope().equals(scope))
				Main.error("variable does not exist in this scope (" + name + ")");
		if (ste.getType().startsWith("function"))
			Main.error("function used as variable (" + name + ")");
	}