Skip to content

repl.md

Latest commit

 

History

History
59 lines (38 loc) · 1.98 KB

repl.md

File metadata and controls

59 lines (38 loc) · 1.98 KB
Raw

FScript REPL Guide

The FScript CLI starts an interactive REPL when you run fscript with no script path and no redirected stdin.

Start

fscript

If you are running from source:

dotnet run --project src/FScript --

Prompts

  • > means a new top-level input.
  • . means the REPL is waiting for more lines for the current input.

Input and execution model

  • The REPL tries to parse/evaluate after each entered line.
  • If the input is syntactically incomplete, it keeps buffering lines.
  • For a pending multiline block, enter two blank lines to force submission. Complete input may execute earlier because the REPL tries each line as it arrives.
  • On successful execution, expression results are printed.
  • If the result is a function value, the REPL prints a typed signature (for example (x: int) -> int) instead of an opaque closure value.

Session state

  • Top-level definitions (let, type declarations, etc.) are retained and available in later inputs.
  • Pure expression entries are evaluated and printed, but are not retained as top-level declarations unless bound with let.

Errors

  • Type and evaluation errors are reported immediately and the pending buffer is reset.
  • Parse errors for incomplete input are deferred while you are still typing. If you force submission (double-Enter on pending input), parse errors are reported.

Exit

  • Ctrl+D (EOF) exits the REPL. If there is pending input, the REPL attempts to run it first.
  • Ctrl+C exits immediately.

Root directory and imports

Set the sandbox/import root with -r/--root:

fscript -r /path/to/project

This sets the runtime filesystem root. Import loading requires an include-capable host/loader; the CLI REPL currently parses submissions without resolving file imports. Use file mode for multi-file scripts.

Mode selection notes

  • fscript <script.fss> runs file mode.
  • cat script.fss | fscript runs stdin mode.
  • fscript (no file, no redirected stdin) runs REPL mode.