source: doc/theses/mike_brooks_MMath/conclusion.tex@ d2e6f84

\chapter{Conclusion}

This thesis performed a detailed examination of the three most important high-level containers in many programming languages: array, linked-list, and string.
The goal of the work is to make containers easier to use, performant and safer.
Since some subset of these three containers are used in almost every program in every programming language, this is a laudable goal.
Accomplishing this goal in C is difficult because these features are poorly designed.
In contrast, \CFA's advanced type system and language features plus my critical design choices made it possible to provide better support with significant safety.
The result is application code that is easier to write, understand, maintain, and safer from hacker attach-vectors.

\section{Lists}

The key takeaway for lists is that intrusive lists can be made easy to use, performant by eliminating implicit memory allocation, and able to simulate wrapped lists, whereas wrapped lists cannot simulate intrusive lists.

\section{Arrays}

The key takeaway for arrays is that the type system must be extended to properly manage array bounds (dimensions) to safely pass arrays to (polymorphic) functions.
By adding a special kind of template constant to \CFA, @[N]@, the type system understands array bounds and implicitly associates these bounds with array instances, statically and dynamically, throughout the programming language.
Array overruns are no longer possible because all subscripting is checked, as in other modern languages.
Subscript checking can be implicitly elided when the compiler is given sufficient information to determine the subscript variable is always in bounds, giving performant execution.

Safe, complex VLA's is another important feature because it replaces unsafe explicit dynamic allocation.
As well, VLA's reduce heap contention in concurrent programs.

Finally, the ability to slice a higher-dimensional array into subarrays is also a powerful and safety critical feature.


\section{Strings}

The key takeaway for strings is that providing powerful and safe block operations for manipulating strings is more important than ultra-level performance.
Manipulating strings is always going to be expensive because of their dynamic variable sizing, as the hardware rarely has string-level operations, possibly only move and compare.
This work designs an expressive set of safe string operations for composing, comparing, and decomposing arbitrary length strings, include complex reading and printing operations.

Creating bespoke storage management for strings has the advantage of faster, more compact storage management due to string sharing, at the cost of additional external fragmentation between the string and general heaps.
With the large amounts of available memory, this approach is a viable tradeoff.



\section{Future Work}

All three forms of containers presented in this work are in their nascence, both in design and implementation.
This work provides the foundation for future \CFA students to add more functionality along with robust and performant implementations.