Scalus Intermediate Representation (SIR)

Scalus generates an intermediate representation (SIR) of your code. SIR is a simplified, lambda calculus-based representation that closely resembles Plutus Core but is easier to work with and optimize.

SIR serves as a bridge between your high-level Scala code and the final Plutus Core output. It preserves the semantics of your program while stripping away Scala-specific constructs, making it ideal for:

• Applying optimizations before final code generation
• Analyzing and debugging the compiled script
• Understanding how your Scala code translates to on-chain logic

Pretty-printing SIR

It’s a good idea to print the SIR to understand what the compiler has generated.

import scalus.*, scalus.sir.SIR
val sir: SIR = ??? // from the previous example
println(sir.show) // pretty-print the SIR
println(sir.showHighlighted) // pretty-print the SIR with colorized syntax highlighting

SIR optimisations

Scalus Intermediate Representation (SIR) can be optimized. Currently, the only optimization is the RemoveRecursivity optimization that inlines let expressions.

import scalus.*, scalus.sir.*
val sir: SIR = ??? // from the previous example
val optimized = RemoveRecursivity(sir)
// or using the `|>` operator
val optimized2 = sir |> RemoveRecursivity.apply