The following technical report is available from http://aib.informatik.rwth-aachen.de: Syntax-Directed Derivative Code (Part I: Tangent-Linear Code) Uwe Naumann AIB 2005-16 This is the first instance in a series of papers on single-pass generation of various types of derivative code by syntax-directed translation. We consider the automatic generation of tangent-linear code by forward mode automatic differentiation implemented as the bottom-up propagation of synthesized attributes on the abstract syntax tree. A proof-of-concept implementation is presented based on a simple LALR(1) parser generated by the parser generator bison. The proposed technique can be generalized easily to provide a method for computing directional derivatives of mathematical vector functions that are implemented as computer programs in the context of computer algebra systems and compilers for scientific computing. The main advantage of the syntax-directed approach to automatic differentiation is its elegance in terms of the implementation.