Furthermore, we show that by utilising quasiquotation, there is hardly any burden on the syntax.
Finally, the chapter also serves as a gentle introduction to \gls{TH} and reflects on the process of using \gls{TH}.
-\section{Tagless-final embedding}
+\section{Tagless-final embedding}%
+\label{sec:tagless-final}
Tagless-final embedding is an upgrade to standard shallow embedding achieved by lifting all language construct functions to type classes.
As a result, views on the \gls{DSL} are data types implementing these classes.
The key difference to our approach is that we specialise the implementation for each of the interpretations instead of providing a general implementation of data type handling operations.
Furthermore, our implementation does not require a generic function to trace all constructors, resulting in problems with (mutual) recursion.
-\Citet{young_adding_2021} added pattern matching to a deeply \gls{EDSL} using a compiler plugin.
+\Citet{young_adding_2021} added pattern matching to a deeply embedded \gls{DSL} using a compiler plugin.
This plugin implements an \haskellinline{externalise :: a -> E a} function that allows lifting all machinery required for pattern matching automatically from the host language to the \gls{DSL}.
Under the hood, this function translates the pattern match to constructors, deconstructors, and constructor predicates.
The main difference with this work is that it requires a compiler plugin while our metaprogramming approach works on any compiler supporting a metaprogramming system similar to \gls{TH}.
Using \gls{TH} or other metaprogramming systems it is possible to add extra code to your program.
The original \gls{TH} paper showed that it is possible to create variadic functions such as \haskellinline{printf} using \gls{TH} that would be almost impossible to define without \citep{sheard_template_2002}.
\Citet{hammond_automatic_2003} used \gls{TH} to generate parallel programming skeletons.
-In practise, this means that the programmer selects a skeleton and, at compile time, the code is massaged to suit the pattern and information about the environment is inlined for optimisation.
+In practice, this means that the programmer selects a skeleton and, at compile time, the code is massaged to suit the pattern and information about the environment is inlined for optimisation.
\Citet{polak_automatic_2006} implemented automatic GUI generation using \gls{TH}.
\Citet{duregard_embedded_2011} wrote a parser generator using \gls{TH} and the custom quasiquoting facilities.
Also, \citet{kariotis_making_2008} used \gls{TH} to automatically construct monad stacks without having to resort to the monad transformers library which requires advanced type system extensions.
\Citet{najd_everything_2016} uses the compile time to be able to do normalisation for a \gls{DSL}, dubbing it \glspl{QDSL}.
-They utilise the quasiquation facilities of \gls{TH} to convert \gls{HASKELL} \gls{DSL} code to constructs in the \gls{DSL}, applying optimisations such as eliminating lambda abstractions and function applications along the way.
+They utilise the quasiquotation facilities of \gls{TH} to convert \gls{HASKELL} \gls{DSL} code to constructs in the \gls{DSL}, applying optimisations such as eliminating lambda abstractions and function applications along the way.
\Citet{egi_embedding_2022} extended \gls{HASKELL} to support non-free data type pattern matching---i.e.\ data type with no standard form, e.g.\ sets, graphs---using \gls{TH}.
Using quasiquotation, they make a complicated embedding of non-linear pattern matching available through a simple lens.
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