Source Files and Imports

Every source file begins with a language header, followed by declarations:

LANGUAGE QUXLANG EN 0.0;

IMPORT std;
::filesystem IMPORT foo_filesystem_utilities;

The header is required in every file, after optional whitespace and comments. QUXLANG, EN, version 0.0, and the terminating semicolon are required. The source bundle assigns each file to a logical module.

Import declarations

IMPORT module_name [AS local_name];
::local_name IMPORT module_name;
IMPORT_IF(condition) module_name [AS local_name];
::local_name IMPORT_IF(condition) module_name;

Module and alias names use lowercase identifiers. An explicitly named import cannot also use AS. Imports are declarations and may appear among other declarations or inside namespaces:

::io NAMESPACE
{
  ::fs IMPORT foo_filesystem_utilities;
}

VAR path io::fs::path;

An import creates an alias in its enclosing declaration scope, visible across source files belonging to that logical module. Repeated imports of the same module under the same name are accepted. Conflicting declarations are errors. Imports are module-private; importing a module does not publicly re-export it. An accessible ALIAS declaration exposes an imported owner:

::implementation IMPORT foo_filesystem_utilities;
::filesystem ALIAS implementation;

Conditional imports

IMPORT_IF evaluates a compile-time condition and includes the import only when it is true:

IMPORT_IF(OS_LINUX) linux_support;
IMPORT_IF(OS_WINDOWS) windows_support;

An explicitly named import may instead use INCLUDE_IF before IMPORT. Combining INCLUDE_IF and IMPORT_IF on one declaration is invalid. Imports always have PRIVATE(MODULE) access; a conflicting privacy scope is invalid.

An inactive import does not require its module to be configured. Conditions follow the declaration availability rules described in Target Availability.

Logical module resolution

IMPORT foolib; requests the logical module foolib from the active target. The target's module map selects its source. The import names a module rather than a physical source file or directory. Qualified lookup uses :::

VAR answer I32 := foolib::imported_function();

Imported declarations retain their privacy and availability restrictions. Declarations from all active source files contribute to their logical module; lookup does not depend on source-file order.

See Source Bundles and Targets, Namespaces, and Privacy.