Lib.rs

Sierra is an intermediate representation between high level Cairo and compilation targets, such as CASM. Sierra code is guaranteed to be "safe"* by construction. Sierra has a primitive, yet rich typing system to express all high level code while guaranteeing safety and allowing for efficient compilation down to the target.

Safety - this means a few things:

1. There are no "panics" / "runtime errors". Every function is guaranteed to return.
2. There are no infinite loops. Moreover, every program "counts" its own steps, and returns when the limit is reached.
3. Builtin library functions are always used correctly.