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Zero-Cost 'Tagless Final' in Rust with GADT-style Enums
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The article demonstrates how to encode the Tagless Final pattern in Rust using GADT-style enums so that the compiler erases the expression tree and emits only arithmetic instructions.
Engineers can write high-level DSL abstractions in Rust without incurring runtime overhead, preserving Rust’s performance guarantees. The technique shows that even sophisticated functional patterns can be compiled away, enabling zero-cost abstractions in systems code.
Written by elseif from the cluster below · every claim links back to a sourceThe three things worth knowing
A GADT-like enum using the never type removes the runtime tag, allowing the compiler to inline and eliminate the interpreter.
The provided eval implementation compiles to a series of leaq and addq instructions, with no dynamic dispatch or heap allocation.
Adopting the pattern requires advanced type-level programming and custom traits, and the zero-cost result depends on release-mode optimizations.
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