Modules and imports

A file util.sere is module util. Imports are resolved, parsed, macro-expanded, and typechecked before the user module is checked. Export bindings become fields on the module object.

Import forms

import util
import util as u
from util import double
from html_lang import html, Html
from math import sqrt
from string import *

Search order:

1. Directory of the importing file, and libs/ next to it
2. Current working directory
3. The stdlib next to sere (or SERE_STDLIB in tests)

util.sere and util.slib both provide module util. .sere wins when both exist. A folder util/ with util/util.sere or util/lib.sere is also import util. Native .c / .lib in that folder or native/ are compiled and linked. The compiler extracts .slib files under .sere-lib/ and links any native objects they contain.

sere init gives you src/ and libs/. Publish reusable code with sere init-lib + sere pack. See Libraries.

Prelude

stdlib/prelude.sere is injected into every module and marked fromPrelude(). It is not re-emitted as user IR. Keep thinking of it as always-on names: abs, min, max, clamp, sign, Int / Float, and macros dbg!, todo!, unreachable!, cfg!.

Module globals

Always in scope:

Host flags

Compile-time bools. A false if branch is not typechecked, so you can call OS-only APIs inside the true arm.

if __windows__:
    windows.message_box("hi")
if cfg!(linux):
    pass

cfg!(windows) (and linux, macos, unix, x86_64, arm64, debug) is a prelude macro that expands to the matching dunder.

Failed C bindings typically return "" / 0 / False rather than throwing. Gate them anyway.

What imports are not

There is no unmodified foreign standard library. Use Sere modules (requests, wsgi, fs, …). An unknown module is ImportError.