This document discusses various programming concepts and techniques including notation, formatting data, regular expressions, programmable tools, interpreters, compilers, virtual machines, programs that write programs, using micros to generate code, and compiling on the fly. It provides examples and discusses tradeoffs between different approaches. The key idea discussed is that notation can make problems easier to solve while dynamic compilation and just-in-time compilation can provide performance benefits over interpreters or ahead-of-time compilers.

1. The Practice of Programming -
Notation
Author : Juggernaut Liu
Date : 2014/04/27

2. Outline
● Introduction
● Formatting Data
● Regular Expressions
● Programmable Tools
● Interpreters, Compilers, and Virtual Machines
● Programs that Write Programs
● Using Micros to Generate Code
● Compiling on the Fly

3. Giles Lytton Strachey, Words and Poetry
Perhaps of all the creations of man
language is the most astonishing

4. Introduction
● If you find yourself writing too much code to do
a mundane job, or if you have trouble expressing
the process comfortably, maybe you're using the
wrong language.
● If the right language doesn't yet exist, that might
be an opportunity to create it yourself.
● Regular Expression, HTML

5. Formatting Data(1)
Sample : Transit different format data.
Type 1
Type 2

6. Formatting Data(2)
Pack one of the format data
Each pack_type needs to
implement its own logic !!

7. Formatting Data(3)
● Define format string
● Logic in one Func

8. Regular Expressions
● Good Sample : grep
Implement a regular expression function

9. Programmable Tools
● Many tools are structured around a special-purpose language.
● Awk
o Selection and Transformation
● Programmable tools often originate in little languages designed
for natural expression of solutions to problems within a narrow
domain.
o eqn : piover2
o TEX : piover 2
● Scripting Languages

10. Interpreters, Compilers, and Virtual Machines(1)
● Interpreters
o Awk, Perl
● Compilers
o most up-front effort and time
o fast execution
● Virtual Machines
o Combine the advantages between Interpreters and Compilers

11. Interpreters, Compilers, and Virtual
Machines(2)
● Parsers
o Tree, usually.
● a = max(b, c/2);

12. Interpreters, Compilers, and Virtual
Machines(3)
● eval (page233, page234)
● Threaded code (page235)
o http://en.wikipedia.org/wiki/Threaded_code
● Java and JVM
o portable
o efficient representations

13. Programs that Write Programs
● The most common program-writing program is a
compiler that translates high level language into
machine code.
● literate programming
o c++ : ///
o java : /** ~ **/

14. Using Micros to Generate Code
● The author have cautioned against using macros
and conditional compilation
● Textual substitution is exactly the right answer to
a problem.
● Be practical and be easy to produce
● It was relatively portable as a high-performance
code

15. Compiling on the Fly(1)
● On the fly, JIT (just in time)
o non-portable
o fast
● VM vs Dynamic compilation
o page 241,242
● The Key idea : Notation
VS

16. Compiling on the Fly(2)
● There are so many special cases that it is more efficient to
create dynamic code for each one that arises than to write
them all out ahead of time or to include conditional tests in
more general code.
● Poc a real on-the-fly compiler
o page242 to page245
● With the right notation, many problems become easier.