Stdlib Overview

FScript ships with a built-in standard library.

It is loaded automatically and available in every script.

Modules

• List
• Option
• Map
• String
• Int
• Float
• Bool

Core rules

• Functions are curried.
• Pipe-friendly usage is preferred.
• Map keys are always string (map indexer type is fixed to string).
• Many parsing/indexing operations return option instead of throwing.

Built-in types and values

FScript also provides a small set of always-available built-in types and values alongside the module functions.

type Environment

type Environment =
  { ScriptName: string option
    Arguments: string list }

This is the shape of the CLI/REPL environment value exposed as Env.

let Env : Environment

Env is injected by the CLI host and REPL:

• Env.ScriptName is Some "..." when running a script file.
• Env.ScriptName is None in stdin mode and the REPL.
• Env.Arguments contains the script arguments passed after --.

match Env.Arguments with
| name :: _ -> print $"hello {name}"
| [] -> print "hello"

type FsKind

type FsKind =
  | File of string
  | Directory of string
  | Missing

Fs.kind returns this union so scripts can pattern match on filesystem lookups without separate boolean probes.

Continue with the module pages for full reference and examples.