There is a {\tt strict} library in Lua, also provided by metalua, which
complains when one tries to access a global variable which hasn't been
initialized, and when a global variable is initialized anywhere but at the
-program's top-level. This catches many errors, especially typos on variable
+program's top-level. This catches many errors, especially typos in variable
names.
However, with a macro-enabled language, we can do slightly better: we add a {\tt