STEPcode (formerly NIST's STEP Class Library) is used with IFC, STEP, and other standards that utilize the technologies of ISO10303 (STEP). It generates C++ and Python from EXPRESS (10303-11) schemas. The code is capable of reading and writing STEP Part 21 exchange files. It also utilizes Parts 22 and 23 (SDAI and its C++ binding).
Perplex, Lemon, and Re2c: A cross-platform lexer/parser replacement for flex and bison
jekyll-rendered static site to replace mediawiki for stepcode.org