# Derivation internals

:::{todo}
Info on _how_ this or that part of the derivation facility is implemented.
Think of useful sections below
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## Derivation task

:::{todo}
how derivation task is represented internally
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## Closure of generators

:::{todo}
how do we implement closure of derived generators using local `StateT`
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## Analysis of data for recursion

:::{todo}
how do we analyse which constructors are (mutually) recursive
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## Derivation tuning via parametrisation

:::{todo}
`DeriveBodyForType` and `DeriveBodyForCon` interfaces, their role and design
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## Dependencies calculation

:::{todo}
An approach on how do we analyse which arguments depend on which in constructors
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## Ordering in the "least-effort" strategy

:::{todo}
How do we calculate in which order arguments should be generated.
Three phases of generation:

- first right-to-left phase
- left-to-right phase
- second right-to-left phase
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