• Lars Johansson (32/32) Feb 11 I’m learning D, and as an experiment I asked Claude.ai to convert

Lars Johansson <lasse 11dim.se> writes:

I’m learning D, and as an experiment I asked Claude.ai to convert 
a C connector to SAP ERP system to D. Claude started by saying 
converting C to D is easy. I pointed to the C github library. 
Claude then requested the needed SAP resources from me, and in 
minutes created a DUB project, with a makefile and documentation. 
There were one bug, a string conversion Claude told me was not 
handled in the C connector, but by the callers of the C 
connector, Claude did a fix and the D connector run flawlessly. 
Without my request Claude created some testcases.

I then asked Claude to parse an XML file to set up a SAP RFC 
call. Not only did Claude do this but he understood by the XML 
structure to create a simple workflow engine without me asking. 
Claude first created his own XML parser, I told him to use DXML 
instead which he did. Now I have a primitive workflow engine that 
can extract (and possible update) data from SAP.

     I asked Claude how he did the conversion.
      “No tools — I did it manually by reading the C header 
(sapnwrfc.h) and translating by hand based on my knowledge of 
both C and D type systems.
     The mapping is mostly mechanical: typedef → alias, C enum → D 
enum, C struct → D struct, function declarations get extern(C) 
linkage. The main decisions were SAP_UC (C char16_t) → D wchar, 
opaque handles → void*, and callback function pointers → D 
function pointer syntax.
     The wrapper layer (Connection, FunctionModule, etc.) was 
modeled after X's  extension architecture — same class hierarchy 
and method patterns, just expressed in idiomatic D with RAII, 
exceptions, and UTF-8↔UTF-16 conversion.”
     Claude did not use any help from BetterC or any of those 
tools they are for humans not AI.

I now have an D SAP connector which I have no use for, it was 
just an experiment. In total there is 75K D code.