I thought that the assembler is a specific program that translates mnemonics into the corresponding machine code. Perhaps in early computing this was done by hand so a person was the assembler (and worked in assembler), but now that is handled by software (and supports various macros). So programming in assembly would generate a stream of text that must be assembled by an assembler. (Although I have heard people refer to programming in assembler as well, just not often.)
I hear people say “program in assembler” but IMO that’s wrong. I’d say you write the code in “assembly language” (or better yet, the actual architecture you’re using like “x86 assembly”) but you “assemble” it with an “assembler”. Kind of like how you could write a program in the “C language” and “compile” it with a “compiler”
