std.fil

std.fil is the simplest layer between your program and the file system. You can check whether a file exists, read the whole content as text, write or append, and for binary content read and write raw bytes.

All of these operations require the right disk capabilities — disk.read to read, disk.write to write — limited to the directories you name when you start the program. That is on purpose: a program without them cannot touch the file system by accident, and a dependency you have not read cannot read files it was never granted access to.

When to use it

Use std.fil to read configuration, save results or process files a user has left behind. The text functions cover the ordinary cases; the byte functions handle images and other binary content. Everything requires the right disk capabilities.

Getting started

bruk std.fil som fil

funksjon start() -> heiltall {
    hvis fil.finnes("notat.txt") {
        skriv(fil.les("notat.txt"))
    } ellers {
        fil.skriv_fil("notat.txt", "Første linje\n")
    }
    fil.append("notat.txt", "En linje til\n")
    returner 0
}

finnes lets you check before you read, and append adds without overwriting. Remember disk.read/disk.write when you start the program.

The functions

Think of the functions in three layers: check (finnes, status), text (les, les_fil, skriv_fil, append) and bytes for binary content (les_bytes, les_byte_liste, skriv_bytes). slett_fil removes a file.

• finnes(sti: tekst) -> bool — True if the file exists at the path.
• skriv_fil(sti: tekst, innhald: tekst) -> heltall — Writes text to the file, overwriting any previous content.
• les_fil(sti: tekst) -> tekst — Reads and returns the whole content of the file as text.
• les(sti: tekst) -> tekst — Reads the whole file as text (short form of les_fil).
• append(sti: tekst, innhald: tekst) -> heltall — Adds text to the end of the file without overwriting.
• skriv_bytes(sti: tekst, data) -> heltall — Writes binary data (a byte buffer) to the file.
• les_bytes(sti: tekst) — Reads the file as binary data.
• les_byte_liste(sti: tekst) -> liste_heltall — Reads the file as a liste_heltall of byte values.
• slett_fil(sti: tekst) -> bool — Deletes the file and returns true if it succeeded.
• status(sti: tekst) -> ordbok_tekst — Returns metadata about the file, such as whether it exists and how big it is.

Good to know

• Without the disk.read/disk.write capability the operations fail with manglar capability — that is not a bug in the code, but the runtime doing its job.
• skriv_fil overwrites; to keep what is there, use append.
• For images and other binary content, use les_bytes/skriv_bytes — the text functions are not safe on raw bytes.

std.fil is one of the modules in the standard library. Everything ships with the runtime — no installation, no external dependencies. See also Documentation for the language and the runtime.

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