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Modules & references

Most designs span more than one file and most reference types they do not define. Two document-level keywords cover this. INCLUDE pulls in other .bhaus files and EXTERN names types that live outside your design.

INCLUDE​

INCLUDE composes a design out of several files. It takes a glob pattern:

VERSION 0.1
INCLUDE types/*.bhaus

The pattern is resolved relative to the directory of the including file, so a file at domain/model.bhaus writing INCLUDE ../shared/*.bhaus reaches out of its own folder. A tool may follow includes recursively, so an included file can include further files of its own.

The effect: every declaration in an included file becomes visible to the including file. A reference in one file can then resolve to a definition in another.

base.bhaus
VERSION 0.1

PROTOCOL Base/Entity:
    PUBLIC getIdentifier(): UUID
model.bhaus
VERSION 0.1

INCLUDE *

CLASS Model IMPLEMENTS Base/Entity:
    PUBLIC getIdentifier(): UUID

Here INCLUDE * pulls in every sibling .bhaus file, so Base/Entity (declared in base.bhaus) is in scope when Model implements it. Without the include the reference stays unresolved and the linter reports it.

note

INCLUDE controls visibility rather than performing text substitution. It does not paste one file into another; it makes the included declarations resolvable. Each file keeps its own VERSION.

EXTERN​

Not every type you reference is one you can or want to define here. A type might live in a framework, a third-party library or a part of the system that falls outside this document. EXTERN declares that such a type exists elsewhere:

EXTERN glsp/Context
EXTERN protocol/DefinitionParams

An EXTERN takes a contextual name and defines nothing. It states that the type is real. Once declared, you can reference it anywhere a type is expected and the reference resolves rather than dangling.

VERSION 0.2

EXTERN glsp/Context
EXTERN protocol/CompletionParams

PROTOCOL TextDocumentCompletionHandler:
    PUBLIC textDocumentCompletion(glsp/Context, protocol/CompletionParams): Unknown

Use EXTERN when you want to mention a type without bringing its full definition into your design. The document stays focused on the part you own and references still type-check.