Also interesting to contrast this to invocation or application (e.g. to invoke or apply). I'm sure there are fair few 'functional dialects' out there!
Incidentally, I find strange misuses of "call" ("calling a command", "calling a button") one of the more grating phrases used by ESL CS students.
Oddly, I never thought of the term library as originating from a physical labelled and organized shelf of tapes, until now.
In Mauchly's "Preparation of Problems for EDVAC-Type Machines", quoted in part in the blog post, he writes:
> The total number of operations for which instructions must be provided will usually be exceedingly large, so that the instruction sequence would be far in excess of the internal memory capacity. However, such an instruction sequence is never a random sequence, and can usually be synthesized from subsequences which frequently recur.
> By providing the necessary subsequences, which may be utilized as often as desired, together with a master sequence directing the use of these subsequences, compact and easily set up instructions for very complex problems can be achieved.
The verbs he uses here for subroutine calls are "utilize" and "direct". Later in the paper he uses the term "subroutine" rather than "subsequence", and does say "called for" but not in reference to the subroutine invocation operation in the machine:
> For these, magnetic tapes containing the series of orders required for the operation can be prepared once and be made available for use when called for in a particular problem. In order that such subroutines, as they can well be called, be truly general, the machine must be endowed with the ability to modify instructions, such as placing specific quantities into general subroutines. Thus is created a new set of operations which might be said to form a calculus of instructions.
Of course nowadays we do not pass arguments to subroutines by modifying their code, but index registers had not yet been invented, so every memory address referenced had to be contained in the instructions that referenced it. (This was considered one of the great benefits of keeping the program in the data memory!)
A little lower down he says "initiate subroutines" and "transferring control to a subroutine", and talks about linking in subroutines from a "library", as quoted in the post.
He never calls subroutines "functions"; I'm not sure where that usage comes from, but certainly by BASIC and LISP there were "functions" that were at least implemented by subroutines. He does talk about mathematical functions being computed by subroutines, including things like matrix multiplication:
> If the subroutine is merely to calculate a function for a single argument, (...)
In the Algol 58 report https://www.softwarepreservation.org/projects/ALGOL/report/A... we have "procedures" and "functions" as types of subroutines. About invoking procedures, it says:
> 9. Procedure statements
> A procedure statement serves to initiate (call for) the execution of a procedure, which is a closed and self-contained process with a fixed ordered set of input and output parameters, permanently defined by a procedure declaration. (cf. procedure declaration.)
Note that this does go to extra pains to include the term "call for", but does not use the phraseology "call a procedure". Rather, it calls for not the procedure itself, but the execution of the procedure.
However, it also uses the term "procedure call" to describe either the initiation or the execution of the procedure:
> The procedure declaration defining the called procedure contains, in its heading, a string of symbols identical in form to the procedure statement, and the formal parameters occupying input and output parameter positions there give complete information concerning the admissibility of parameters used in any procedure call, (...)
Algol 58 has a different structure for defining functions rather than procedures, but those too are invoked by a "function call"—but not by "calling the function".
I'm not sure when the first assembly language with a "call" instruction appeared, but it might even be earlier than 01958. The Burroughs 5000 seems like it would be a promising thing to look at. But certainly many assembly languages from the time didn't; even MIX used a STJ instruction to set the return address in the return instruction in the called subroutine and then just jumped to its entry point, and the PDP-10 used PUSHJ IIRC. The 360 used BALR, branch and link register, much like RISC-V's JALR today.
> Dennis Ritchie encouraged modularity by telling all and sundry that function calls were really, really cheap in C. Everybody started writing small functions and modularizing. Years later we found out that function calls were still expensive on the PDP-11, and VAX code was often spending 50% of its time in the CALLS instruction. Dennis had lied to us! But it was too late; we were all hooked...
https://www.catb.org/~esr/writings/taoup/html/modularitychap...
(In the way you'd call upon a skill, not in the way you'd call upon a neighbor.)
In in Tcl, `if` is called a "command".
I don't know enough Smalltalk to be sure but I think to remember it has a similar approach of everything is an object and I wouldn't be surprised if they'd coerced control flow somehow into this framework.
Also Forth comes to mind, but that would probably be a stretch.
It just means to start doing something, no great mystery.
In an imperative programming language with eager evaluation, i.e. where arguments are evaluated before applying the function, implementing `if` as a function will evaluate both the "then" and "else" alternatives, which will have undesirable behavior if the alternatives can have side effects.
In a pure but still eager functional language this can work better, if it's not possible for the alternatives to have side effects. But it's still inefficient, because you're evaluating expressions whose result will be discarded, which is just wasted computation.
In a lazy functional language, you can have a viable `if` function, because it will only evaluate the argument that's needed. But even in the lazy functional language Haskell, `if` is implemented as built-in syntax, for usability reasons - if the compiler understands what `if` means as opposed to treating it as an ordinary function, it can optimize better, produce better messages, etc.
In a language with the right kind of macros, you can define `if` as a macro. Typically in that case, its arguments might be wrapped in lambdas, by the macro, to allow them to be evaluated only as needed. But Scheme and Lisp, which have the right kind of macros, don't define `if` as a macro for similar reasons to Haskell.
One language in which `if` is a function is the pure lambda calculus, but no-one writes real code in that.
The only "major" language I can think of in which `if` is actually a function (well, a couple of methods) is Smalltalk, and in that case it works because the arguments to it are code blocks, i.e. essentially lambdas.
tl;dr: `if` as a function isn't practical in most languages.
So at least in Finnish the word "call" is considered to mean what it means in a context like "a mother called her children back inside from the yard" instead of "call" as in "Joe made a call to his friend" or "what do you call this color?".
Just felt like sharing.
A fairly recent example, "salty". It's short, and kinda feels like it describes what it means (salty -> tears -> upset).
It sounds like "call" is similar. It's short, so easy to say for an often used technical term, and there are a couple of ways it can "feel right": calling up, calling in, summoning, invoking (as a magic spell). People hear it, it fits, and the term spreads. I doubt there were be many competing terms, because terms like "jump" would have been in use to refer to existing concepts. Also keep in mind that telephones were hot, magical technology that would have become widespread around this same time period. The idea of being able to call up someone would be at the forefront of people's brains, so contemporary programmers would likely have easily formed a mental connection/analogy between calling people and calling subroutines.
I think the early BASIC's used the subroutine nomenclature for GOSUB, where there was no parameter passing or anything, just a jump that automatically remembered the place to return.
Functions in BASIC, as I remember it, were something quite different. I think they were merely named abbreviations for arithmetic expressions and simple one line artithmetic expressions only. They were more similar to very primitive and heavily restricted macros than to subroutines or functions.