At my last workplace, I wrote transpilers (or just compilers if you prefer) from mainframe languages (COBOL, JCL, BASIC etc.) to Java (in Rust!). Legacy code is full of surprises. In the roughly 200k lines of COBOL that I had the (dis)pleasure of working with, I saw some wonderful hacks to get around the limitations of the system. Mainframes are also chock full of history. Base-10 numerics This is the first thing that stood out to me when I looked at COBOL code, a data-definition (the phrase for...