I used to code for a language called "Spad" — originally shipped in 1972(?). The syntax: x : t = e Was called "headform" and was the only syntactic form f

I used to code for a language called "Spad" — originally shipped in 1972(?). The syntax: x : t = e Was called "headform" and was the only syntactic form for the whole language. (Expressions used a shunting yard algorithm to desugar into a sequence of headform.) The language included modules, classes, parameterics, functions, constraints, ..., whatever.