That wouldn't work because it is already valid Lua code with a different meaning. Lua parses it as a declaration of a local variable called f followed by an ass

That wouldn't work because it is already valid Lua code with a different meaning. Lua parses it as a declaration of a local variable called f followed by an assignment to a variable named close: local f close = io.open("foo.txt") Despite the lack of semicolons, Lua is a free-form language and newlines are treated the same as any other whitespace character.