Introduction to Programming
Well, Kind Of.
THATCamp New England 2010
Julie Meloni // @jcmeloni // jcmeloni@gmail.com

What’s missing in the slides...
• A lot of extemporaneous talking about how
everyone is already a programmer.
• In fact, you all probably know a lot of this, but
just didn’t know the terms.
• What’s more, the applications of the future come
from the needs of the present: your needs.
▫ When you can articulate them to someone who
can do the codework, we all win.

Why Program?
• Express complex logic and perform
computations.
▫ We make the computer do what we want it to do.
▫ These behaviors come from our imaginations.
▫ The processes come from our needs and desires.
• Do things that take a long time or are difficult
for humans to do (counting, comparing,
repeating)

What is a “Programming Language”?
• An artificial language with a limited purpose
• A means of expressing computations (math) and
algorithms (logic)
Thanks, @wayne_graham. I “repurposed” some of your content on this slide and the next.

What Does a Programming Language
Look Like?
• ...a lot like human language. They have:
▫ Syntax (form)
▫ Semantics (meaning)
 signs/words (variables, symbols, numbers,
strings)
 expressions
 flow control (decisions, conditions, loops,
narrative)
 complex entities (methods, structures, & objects)

A Few Types of Programming Uses
• Job control or shell scripting; text processing
• Graphical User Interface (GUI) programming
• Application-specific programming
• Web applications
▫ Front-end
▫ Back-end

Some Programming Languages You May
Have Heard About
• C++
• Java
• JavaScript (completely unrelated to the former)
• Perl
• Python
• Ruby
• PHP

A Few Basic Programming Components
(pretty much regardless of language)
• Variables & Arrays
• Operators
• Flow Control
• Functions
Putting together these pieces adds up to
programming (or scripting, or in general “writing
some stuff to tell the computer what to do”)

Variables & Arrays
• A variable is a bucket that holds one piece of
information.
• Examples (language doesn’t matter here; the
concept does):
▫ $string_variable = “THATCamp”;
▫ $numeric_variable= 4;
▫ $myname = “Julie”;

Variables & Arrays
• An array is a type of variable (or bucket) that holds
many pieces of information.
• Example (language doesn’t matter here; the
concept does):
▫ $THATCamps = array(“Prime”, “New England”,
“Pacific Northwest”)
 $THATCamps[0] holds “Prime”
 $THATCamps[1] holds “New England”
▫ $THATCamps = array(“1” => “Prime”; “NE”=> “New
England”, “PNW” => “Pacific Northwest”)
 $THATCamps[“NE”] holds “New England”

Operators
• Arithmetic
▫ +, -, *, / (add, subtract, multiply, divide)
• Assignment
▫ = (“Assign the value of 4 to the variable called a”)
 $a = 4;
▫ += (“Add the value of 5 to the variable that already
holds 4”)
 $a += 5; // $a now holds 9
▫ .= (“Attach the value ‘World’ to the end of ‘Hello’ to
make a new value for the string variable”)
 $string = “Hello”;
 $string .= “World”; // would print “HelloWorld” (no
space because we didn’t add that!)

Operators
• Comparison
▫ == (“when I compare the value in variable a to the value in variable be,
that comparison is true”)
 $a == $b
▫ != (“when I compare the value in variable a to the value in variable be,
that comparison is not true”)
 $a != $b
▫ === (“when I compare the type of and value in variable a to the type of
and value in variable be, that comparison is true”)
 $a === $b
▫ >, >= (“the value of variable a is greater than (or greater than or equal
to) the value of variable b”)
 $a > $b
▫ <, <= (“the value of variable a is less than (or less than or equal to) the
value of variable b”)
 $a < b

Operators
• Logical
▫ && (and)
▫ || (or)
▫ ! (not)

Flow Control (conceptual structures virtually
independent of language, although might look a
little different)
• if
if (something is true) {
do something here
}
• if ... else ... else if
if (something is true) {
do something here
} else if (something is true) {
do something here
} else {
do something here
}

Flow Control (conceptual structures virtually
independent of language, although might look a
little different)
• while
while (something is true) {
do something here
}
• for
for (something is true) {
do something here
}

Flow Control (conceptual structures virtually
independent of language, although might look a
little different)
• switch
switch (some_variable) {
case “some_value”:
do something here
break;
case “some_other_value”:
do something here
break;
default:
do something here
}

Procedures and Functions
• Scripts can contain linear, procedural code.
• Scripts can also contain references to reusable bits
of code, called functions.
▫ Built-in language functions
▫ Functions you write yourself.
• [Note at this point in the presentation I talked a bit
about how every element you see in an application
can be boiled down to its logical structures and the
code you want to execute within those structures.]

Some Application Examples
• Static web site with some snippets of interactivity
▫ The example I used was a simple form on a web site.
• A library catalog with a content discovery mechanism
▫ I showed VIRGO (http://search.lib.virginia.edu).
• Custom Web-based application like NINES
▫ That would be http://nines.org
• WordPress/dynamic platform such as Omeka
▫ I showed two Omeka sites: Lincoln at 200 (http://lincolnat200.org) and
MITH’s Vintage Computers (http://mith.umd.edu/vintage-computers/)
▫ Clicked through to show exhibit & item conceptually same in both sites
(because of framework).
▫ Data goes in, data is pulled out; it exists in one place but accessed many ways

Let’s Design an Application
• What do you want it to do?
• What type of programming is required?
• Does language matter?
• What elements of programming are required (GUI?
Actions? Frameworks? etc)
• What can you leverage?
• What comes next?
▫ Being logical, being incremental, being procedural,
being functional, being a programmer...and then
talking to specialists.

And then...
• Asked the group for examples of ideas/tools/things
they wanted to do. Some examples:
▫ Discover similarities between two data sets
▫ Social annotation of images/primary sources
▫ Visualizing relationships between data
• Turns out you need three things for all of the
projects/ideas people had:
▫ Primary material
▫ Metadata
▫ Interface/use thoughts

And THEN...
• We walked through several examples and kept coming
back to:
▫ Logical construction of actions; explain it to someone in
“pseudocode”
 “If I click on this link, I want X to happen, and if I select this
form element and that form element together, I want Y to
happen”, etc.
▫ Most processes can be broken into smaller processes, all
loopy or controlled structures in some way.
▫ If you can think of what you want to see or do, you can tell
the computer how to do it so you can see it.
▫ You don’t need to be a Comp. Sci. person to do any of the
above – just an imaginative and relatively logical person.