Pure Research

• Agda is Pure Research.
• LR(k) theory is Pure Research.
• LL(k) theory is Pure Research.
• Finite Automata theory is Pure Research.
• Lexical Analysis is Pure Research

Pure Research in software means creating the envelope / environment / context in which practical languages can be built.

Applied Research

• C is Applied Research.
• Yacc is Applied Research.
• LEX is Applied Research.
• PEG is Applied Research.
• Javascript is Applied Research
• Common Lisp is Applied Research (as opposed to Lisp).

A university degree in Applied Research is called a BASc.

Applied research is also known as Engineering.

Pure Research Is Not Programming

What is Programming?

• Programming is about finding Russian Dolls.
• Nesting.

Examples

GOTOs - Structured Programming

Structured Programming gave us nesting of GOTOs.

Global Variables - Scoping

Scoping gave us nesting of global variables.

Denotation Semantics - Phases

Denotational Semantics is tamed using passes/phases.  

Aka nesting.

https://www.amazon.ca/Realistic-Compiler-Generation-Peter-Lee/dp/0262121417

Peter Lee and Uwe Pleban

Docker

Docker nests environments.

S/SL

Syntax Semantic Language (not Secure Sockets Layer).

S/SL report 

https://archive.org/details/technicalreportc118univ

source code:

https://research.cs.queensu.ca/home/cordy/pub/downloads/ssl/

S/xL is the syntax portion.  A little language for parsing.  About 14 operations.

x/SL is the semantics portion.  A little language for expressing operations on data. 

x/SL is the real gem. 

• SL shows how to talk about data without using any built-in operators
• SL is dataless. (!).   E.G. there is no '+' operator.
• FP is SL wannabe.  
• SL shows how to chunk Software Architecture.
• See, also, Peter Lee's work Denotation Semantics - Phases - it chunks Denotational Semantics in a way that resembles SL.

UNIX® Pipes

• Isolation
• Sledgehammer approach - when a process dies (or is killed), the O/S cleans up all data and control flow (The Stack).

Rust

Rust provides UNIX® like isolation of data.

Data ownership was explored and implemented in FBP^[1] and variants of Visual Frameworks^[2] and, probably, other technologies.

UNIX® pipes don't need data ownership, because data is transfered by-value via pipes.

Ownership is just an optimization that allows memory sharing^[3].

Bash

• Uses UNIX® Pipes.
• Nesting occurs when a .bash script calls another .bash script
• Composite node: script
• Leaf node: command (e.g. written in, say, C). 

Software Tools

• https://books.google.ca/books/about/Software_Tools.html?id=kIxQAAAAMAAJ&redir_esc=y
• IMO: maybe the best book on programming ever written
• Nesting is possible even with FORTRAN
• 
  

Diagrams

• Diagrams show nesting
• Unclean: rectangle that intersects another rectangle - intuition says that this needs to be cleaned up
• Diagrams show scoping, yet textual code labors with this concept

For example Fig. 1

Fig. 1 Nested Diagram

is more expressive than

{

  {

    …

  }

}

(especially when deep nesting occurs, and when problems are "complex").

Trees

• Trees are data structures that express nesting
• Non-overlapping
• 
  

Lisp

• Lisp expresses nesting using (...)
• Lisp can express lists inside of lists
• Composite node: list
• Leaf node: atom
• 
  

Syntax

PL^[4] Syntax is a way to wrap nesting, to make it "prettier".

if…then…else… can be expressed as

(if (…) (…) (…)) 

or

if (…) then

  …

else

  …

end if

Syntax can be used to enable syntax checking.

E.g. Pascal-like languages can be syntax checked, while Lisp cannot.^[5]

Syntax checking is only good for simple error checks, e.g. typos.  After such initial checking, syntax checking is no longer needed.^[6]

Footnotes

• In documents, nesting is supported by footnotes.
• Footnotes handle only one level of nesting (what about footnotes in footnotes in …?)
• 
  

HTML

• HTML is (strictly) nested.
• HTML is no-code for GUI building.
• 
  

Callbacks

Callbacks are textual nestings.

Callbacks are a good example of where text-only fails.^[7]

Functions

Functions are one-in-one-out nestings of code.

Javascript FileReader () is an example of where more nesting needs to be expressed and where text-only fails to express such concepts in a simple way.

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[1] https://jpaulm.github.io/fbp/

[2] An OEM product, now defunct.

[3] Note that the concept of memory sharing makes no sense if one tries to design a language for distributed computing.

[4] PL means Programming Language

[5] Lisp tends to use kludges added to the editor to provide syntax checking.

[6] Except for checking syntax of newly added code.

[7] Exceptions are another text-only kludge.