:sig
SharedUnit* unit_load(String file_name)

:params
file_name : UCE file to load
return value : loaded shared unit, or `null` if the unit could not be loaded

:desc
Loads a UCE compilation unit and returns its in-memory `SharedUnit` record.

This is a low-level runtime helper. Most application code should prefer `unit_render()`, `unit_call()`, `component()`, or `component_render()`.

:see
unit_render
unit_call
load

:related
**PHP:** `include`, `require`, autoloaders, and lazy-loading of modules
**JavaScript / Node.js:** Dynamic `import()`, lazy module loading, or require-on-demand patterns