Imports & Modules

Every .mi file is a module. Importing a module evaluates it and returns a record containing all of its top-level bindings. You bind that record to a name and access its members with dot notation — no special export lists or visibility modifiers.

Local Imports

Use import with a file path (relative to the importing file’s directory):

math = import "lib/mymath.mi"

area = math.circle_area 5

The result of import is a record, so math.circle_area and math.pi access individual bindings from the imported file.

A Complete Example

-- Suppose lib/mymath.mi contains:
--   pi = 3.14159
--   circle_area r = pi * r * r

-- We can inline the same definitions here to demonstrate:
pi = 3.14159
circle_area r = pi * r * r

circumference r = 2 * pi * r

build =  {target = c, os = linux, arch = x86_64}
pi = 3.14159
circle_area = <closure>
circumference = <closure>

URL Imports

Remote modules are imported the same way — just use a URL:

collections = import "https://example.com/milang-stdlib/collections.mi"

total = collections.sum [1, 2, 3]

The compiler downloads the file and caches it locally. On subsequent runs the cached version is used.

Pinned Imports with import'

URL imports must be pinned by their SHA-256 hash using the import' form:

lib = import' "https://example.com/lib.mi" ({sha256 = "a1b2c3..."})

If the downloaded content does not match the hash, compilation fails. The milang pin command computes the hash for you:

$ milang pin https://example.com/lib.mi
sha256 = "a1b2c3d4e5f6..."

C Header Imports

When the path ends in .h, the compiler parses the C header and exposes its functions as milang bindings. See the C FFI chapter for details.

m = import "math.h"
result = m.sin 1.0

You can also associate C source files and compiler flags with import':

lib = import' "mylib.h" ({src = "mylib.c"})
answer = lib.add_ints 3 4

Circular Imports

Milang supports circular imports. When module A imports module B and B imports A, the resolver detects the cycle and marks the circular bindings as lazy (thunks) to break the dependency. Both modules load correctly and can reference each other’s bindings.

Diamond Imports

If two modules both import the same third module, it is loaded and evaluated only once. The two importers share the same record, so there is no duplication or inconsistency.

Visibility

All top-level bindings in a .mi file are exported — there is no private/public distinction. If you want to signal that a binding is an internal helper, use a naming convention such as an underscore prefix (_helper), but the compiler does not enforce this.