# `Schooner.Eval.Error`
[🔗](https://github.com/ausimian/schooner/blob/1.0.0/lib/schooner/eval/error.ex#L1)

Exception raised by the evaluator for runtime and syntactic failures.

The `:reason` field is a structured term — atom or tagged tuple — meant
to be machine-matchable in tests. The pretty `:message` is generated
lazily so assertions can pin behaviour without coupling to wording.

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*Consult [api-reference.md](api-reference.md) for complete listing*