toolchains
Interpreter
The edit-run path that prioritizes feedback speed while sharing language semantics, stdlib behavior, and diagnostics with the compiled modes.
The interpreter is the default execution path behind fidan run.
Why it matters
It is not a separate “demo mode.” The interpreter is a first-class runtime mode that shares:
- language semantics
- builtin behavior
- stdlib dispatch
- diagnostics
- null-safety and race-analysis expectations
with the compiled modes.
When to use it
- rapid edit-run iteration
- experimenting with syntax
- debugging behavior before caring about final binary size or peak speed
- running scripts where startup speed matters more than AOT output
Command
fidan run app.fdnRelationship to the JIT
The interpreter can hand hot functions to the Cranelift JIT when the threshold is reached. That means the normal run path gives you:
- interpreted fallback everywhere
- native acceleration for eligible hot paths
without changing your command.
Tracing and replay
The interpreter path also supports:
--trace none|short|full|compact--replay <bundle-or-id>- sandbox flags
- hot reload with
--reload
Recommendation
Use the interpreter as the daily development default, then move to AOT builds when you want release-style performance or artifacts.
