I remember once upon a time I paid for Intel compilers and tools and it was pretty worth it for the application at hand. Now, I am building an object oriented database engine and am considering using a Fortran back end to compile a simple scripting language on the fly. This seems pretty straightfoward, but what's the licensing like these days? Is this open source?
All the Intel oneAPI Toolkits are open source, you can download them for free. Please find the below links for downloading the latest Intel Base and HPC Toolkits. https://www.intel.com/content/www/us/en/developer/tools/oneapi/base-toolkit-download.html https://www.intel.com/content/www/us/en/developer/tools/oneapi/hpc-toolkit-download.html
To access older releases you need a version that includes Intel Priority Support, the free versions do not include this. Here is a link to the online store to get a commercially supported version. Please find the below link: https://softwarestore.intel.com/