I/O, Modules, Capabilities, and Explicit Effects

The pure executable profile keeps host effects outside ordinary evaluation and exposes only pinned output behavior in the reference runtime.

At a glance

LISPEX

(begin (display "answer=") (write 42) (newline) 0)

Result

OUTPUT

answer=42
0

display, write, and newline behavior use canonical guest rendering and deterministic output order.
CLI file/stdin selection and source labels are invocation concerns, not new language bindings.
External capabilities must be explicit and versioned rather than discovered by a host-global fallback.

Ports, filesystem, networking, time, randomness, and unrestricted host evaluation are not in the current pure profile.
Target-language emission is not a Lispex execution mode.