i've been reading the unix programming environment from 01983 this week (the old testament of kernighan and pike), about 35 years later than i really should have. awk is really one of the stars of the book, the closest thing in it to currently popular languages like js, lua, python, perl, or tcl. (what awk calls 'associative arrays' js just calls 'objects'.)
the 7th edition unix version of awk from 01979 https://www.tuhs.org/cgi-bin/utree.pl?file=V7/usr/src/cmd/aw... (from https://www.tuhs.org/Archive/Distributions/Research/Henry_Sp...) is only 2680 lines of source code, which is pretty astonishing. the executable is 46k and ran in the pdp-11's 64k address space. as far as i can tell, that version of awk, and also the one documnted four years later in tupe, didn't even have user-defined functions. neither did the v7 version of the bourne shell, i think
bc, however, did