Having done some cursory searching of the internet, it is clear to me that there is a very well-developed theory of how to do calculus over function fields, such as fields of Laurent series in a single indeterminate with coefficients in a finite field (viz. Drinfeld modules, the Carlitz exponential, etc.) However, there seems to be nothing about the case where the function field has coefficients in a field of characteristic zero ($\mathbb{C}$, number fields, local fields, etc.). Is this because characteristic zero gunks up the theoretical machinery, or because no one has really explored it? Or do I just not know where to look for this?
References to articles/books about this topic (if they exist) would be much appreciated.