The (actually second) BASIC interpreter on the Amiga was made by Microsoft. It was great and horrible at the same time. Great because it had while-loops, labels instead of line numbers, and basic (no pun intended) support for the Amiga GUI, i.e you could open windows and create menus. Horrible because it was super slow and, for some reasons unknown to me, Microsoft had decided to not implement stack frames for subroutines. So, all local variables in subroutines were static and recursions were not allowed.
The weird thing: You still had to write the "STATIC" keyword although all subroutines were static anyway! (I assume the STATIC keyword was optional in the other Microsoft BASIC version and non-static subroutines were supported there)
A$ = "ABCD"
MID(A$,2,2)="12"
PRINT $A
>A123
x = [1,2,5,6]
x[2:2] = [3,4]
print(x)
As DonHopkins notes, this appears substantially identical to the assign-equals operators which are generally thought of as "easy and convenient" rather than "weird". How is the line of code "a *= 7" meaning
"whatever the current value of a is, multiply that by 7 and assign the result to a"
weirder than the line 'a$ = REP("123",4,0)' meaning
"whatever the current value of a$ is, do a string replacement on it and assign the result to a$"?
Yes, it actually did exactly what it sounds like!
Chalk one up for DEC and BASIC. What other programming languages support that feature, huh?
DECSYSTEM 20 BASIC User's Guide: LISTREVERSE command
LISTREVERSE
LISTNHREVERSE
LISTREVERSE and LISTNHREVERSE print the contents of the
user's memory area in order of descending line numbers.
LISTREVERSE precedes the output with a heading,
LISTNHREVERSE eliminates the heading.
LISTREVERSE
EQUIV 10:53 13-NOV-75
40 END
35 PRINT "THE EQUIVALENT CURRENT IS",I, " AMPERES"
25 I=E1/R
10 INPUT R
5 INPUT E1
READY
Same might go for a terminal with no scrollback...
Come to think of it, this sounds actually rather useful. Had this been available when I was programming on the BBC Micro, I bet I'd have used it.
A$.REP("123", 4, 0)
perl -le '$A = "ABCDEF"; substr($A, 3, 0) = 123; print $A'
ABC123DEF
Mind-blowing BASIC example from the 1970's:
The result is ABC123DEF -- at position 4 (strings start at 1), replace 0 characters with "123". So the REP function looks at the statement it's part of, finds the variable that is being assigned to, and uses that as the starting string (!). It's kind of like a function, only with a weird implied variable that only works in an assignment.You can't just PRINT the result directly, because then how would REP know what the string to change is?
Nowadays "weird" syntax has some solid foundational reason why it's useful or important. This not-really-a-function, though, simply has no justification whatsoever.
(This example is from the BASIC embedded in the Tektronix 4050 terminal).
There are enough variants of BASIC that there's a really nifty handbook with the differences at https://archive.org/details/Basic_Handbook_2nd_Edition_1981_...