vector->list(3scm)

📦 version 0-unstable-2024-02, in nixpkgs unstable

💜 vector->list(3scm) — or, how to glow-up between vectors and lists

okay bestie, welcome to the Scheme Programmer's Manual ✨ this little page is all about the two-way pipeline between vectors and lists, and honestly? it's giving "easy A energy" 🎀

🌸 NAME 🌸

vector->list, list->vector — the conversion girlies between vectors and lists 💅

📚 LIBRARY 📚

so you gotta import it first, obviously 🫶

(import (rnrs))                     ;R6RS
(import (rnrs base))                ;R6RS
(import (scheme r5rs))              ;R7RS
(import (scheme base))              ;R7RS

✨ SYNOPSIS ✨

here's the whole menu, no cap 😌

(vector->list vector)
(vector->list vector start)         ;R7RS
(vector->list vector start end)     ;R7RS
(list->vector list)

🦋 DESCRIPTION 🦋

okay so vector->list hands you back a newly allocated list made of the objects sitting in the elements of vector. fresh out of the oven, brand new, nobody else's 🍓

and list->vector? it returns a newly created vector initialized to the elements of the list list. also new, also iconic 👑

in both of these procedures, order is preserved — the vibes stay in the exact same sequence, periodt 🌈

R7RS — heads up! vector->list is limited to the elements between start (inclusive) and end (exclusive). these arguments default to 0 and the length of the vector, respectively. so like, you can slice if you want to slice 💖

🧚 IMPLEMENTATION NOTES 🧚

  • Chez Scheme, Loko Scheme — sooo the empty vector is a unique object, which means (list->vector '()) does not return a newly allocated vector. it's the same little guy every time 🫶

🎀 RETURN VALUES 🎀

both procedures return a single value — either a vector object or a list. one value, no drama 💀

⭐ EXAMPLES ⭐

watch and learn bestie:

(vector->list '#(dah dah didah))
            => (dah dah didah)

(list->vector '(dididit dah))
            => #(dididit dah)

ate, no crumbs 💅

💀 COMPATIBILITY 💀

these procedures work the same everywhere, with one tiny exception: the start and end arguments, which are only present in the R7RS variant of vector->list. so if you're on something older, don't come for those extra args, they're not invited 🙈

😭 ERRORS 😭

this procedure can raise exceptions with the following condition types:

  • &assertion (R6RS) — the wrong number of arguments was passed, or an argument was outside its domain. basically: you did too much, or you did too little 🤷‍♀️
R7RS — the assertions described above are errors. implementations may signal an error, extend the procedure's domain of definition to include such arguments, or fail catastrophically. yes, catastrophically, like full-on main character meltdown 💀
in particular, if list->vector is passed a cyclical list then the procedure may not terminate. forever loop era, and not in a cute way 😭 please don't do this to yourself.

🔥 SEE ALSO 🔥

go read those next, iykyk 📖

👑 STANDARDS 👑

R4RS, R5RS, R6RS, R7RS — certified by literally everyone 🌈

🕰️ HISTORY 🕰️

these procedures first appeared in R2RS — ancient, historic, grandmother energy 🫶. they were left out of IEEE Scheme. but in spite of this, list->vector appears as an example in the standard. not me being excluded and still showing up in the textbook 😭💅

🌸 AUTHORS 🌸

this page is part of the scheme-manpages project. it includes materials from the RnRS documents. more information can be found at https://github.com/schemedoc/manpages/. slay 🎀

and that's the whole page bestie!! 💖 dated 2023-01-24, and filed under that vector->list(3scm) name — now go convert some data structures, you got this 🦋✨

📦 where this page comes from