Grace Hopper on her compiler (operational in 1952): “Nobody believed that,” she said. “I had a running compiler and nobody would touch it. They told me computers could only do arithmetic.”
I knew she discovered the first computer bug, but I didn’t actually realise she invented the compiler.
Another article goes into more detail:
“She did this, she said, because she was lazy and hoped that “the programmer may return to being a mathematician.” Her work embodied or foreshadowed enormous numbers of developments that are now the bones of digital computing: subroutines, formula translation, relative addressing, the linking loader, code optimization, and even symbolic manipulation of the kind embodied in Mathematica and Maple. ”
(While I’m at it, this is an ok article on Ada Lovelace though it doesn’t mention that her ‘Notes’ were three times the length of the article she was translating, or her idea for the first computer program.)