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Made with KolourPaint and screenshots from Kate (with the GitHub theme).
Made with KolourPaint and screenshots from Kate (with the GitHub theme).
It’s commonly used in math to declare variables so I assume programming languages borrowed it from there.
More specifically, they’re borrowing the more mathematical meaning of variables, where if you say x equals 5, you can’t later say x is 6, and where a statement like “x = x + 1” is nonsense. Using “let” means you’re setting the value once and that’s what it’s going to remain as long as it exists, while “var” variables can be changed later. Functional languages, which are usually made by very math-y people, will often protest the way programmers use operators by saying that
=is strictly for equality and variable assignment is:=instead of==and=in most C-style languages.Unless you’re in JS.
BASIC uses (used?) it to declare variables. (I don’t know if earlier languages did.)
Not that that’s a reason for other languages to copy it.
Doesn’t Basic use
Dim a As String?Older variants used DIM for arrays and LET for other variables. DIM was originally called that because it was setting the dimensions of the array.
In modern BASIC variants, DIM has become a backronym: “declare in memory”.
TIL. I always thought it was a backronym for
declare in (yo) momma.TIL Backronyms and cuil BASIC technicalities Much obliged all
Even older variants required both a let to declare the variable and a dim to set its size.
I remember a
REDIMcommand, but I really can’t remember what basic it’s from.The first programming language I used was Visual Basic (both VBA in Excel, and VB3 then VB6). I think it used redim to resize arrays.