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==Variables==

Variables, as the name implies, are dynamic objects in programming which change based on their context. That is, for instance, $variable can always be returned with $variable but the value returned may change. In high-level languages, there are generally three types of variables: '''Scalars''' (single values), '''Arrays''' (or lists), and '''Associative Arrays''' (or hashes).  In more mid-level languages, variables are broken up further into integers, character arrays, floats, booleans, etc.  

===Scalars===

A ''scalar'' is the simplest form of a variable, as it is a single object. You may recall a person's name or a single number. These are typically used for basic things like running the same equation (Think X + 10 =) when you'll need changing data to test.

===Arrays===

An ''array'' is a bit more complex than a Scalar. Arrays are formed from multiple scalars and can contain scalars or predefined, static strings. You may have a variable for a classroom, which inside lists <i>all</i> the names rather than one.

===Associative Arrays===

An ''associative array'' is similar to an Array, but with two fields that compare each other instead of individual strings. For instance you might have an array that compares the classes first names to last so that at any point if you know the person's last name, you can find their first.

===Combining Variables===

The true benefit of variables comes when you combine them. You may have a ''scalar'' called ''number'' to recall an element in ''array'' called ''months'' to pull a month's name by its chronological number, or use a ''scalar'' called ''last_name'' that refers to your ''hash'' called ''full_names'' so that every time you recall last_name it associates the first.

==Validity==

''Validity'' is a simple concept. If a condition is true, the [[#Conditionals|conditional]] or [[#Loops|loop]] will act accordingly. Likewise if it's false, that is a 0, empty string, or incorrect comparative operator, it will treat the loop or conditional in the opposite manner.

==Comparative Operators==

Comparative operators are used when you want to return a true value by comparing two other values. You might have a 7 and a 5. Since they're not empty strings, (7) would always be true. (5) would likewise be true, but is 7 <i>less than</i> 5? Common comparative operators are ''and, or, equal to, not equal to, greater than, greater than or equal to, less than,'' and ''less than or equal to''. They return true when the mathematical value is satisfied.

<center>
{|class="wikitable"
!colspan="3"|Comparative Operators and Symbols
|-
|Literal
|Shorthand
|Symbolic
|-
|And
|and
|&&
|-
|Or
|or
|<nowiki>||</nowiki>
|-
|Equal to
|eq
|==
|-
|Not Equal to
|ne
|!=
|-
|Greater than
|gt
|>
|-
|Greater than or equal to
|ge
|>=
|-
|Less than
|lt
|<
|-
|Less than or equal to
|le
|<=
|}</center>

==Conditionals==

Typically found as ''if, unless, else'', or ''else if'', conditionals take action according to the <i>validity</i> of a condition. That means they either do an action contained in the block of code, or skip past the block altogether depending on the conditional used.

===If===

The most common conditional is ''if''. ''If'' your condition returns true, for instance, if (5 < 7) or if (5 != 7), it proceeds with the block and performs actions. If it returns false, it ignores the block altogether and goes to the next.

===Unless===

''Unless'' is the exact opposite of if. It only continues with the block if the condition isn't met and returns a false value. You can say ''unless'' a variable is less than a limit (maybe unless ($variable < $limit)) allow it to do anything in the block. This conditional can be reworded into an if, and you should use what feels more natural to you ("if exists $variable" is the same as "unless not exists $variable")

===Else===

''Else'' is plain conditional in that it doesn't test anything except the previous conditional. For instance you could have a statement that reads unless this variable is less than a limit, allow it to do this ''else'' print "You're not allowed!" If the previous condition is not satisfied, it will always run. If it was, it will never run.

===Else if===

Else if, or more commonly ''elseif'' is exactly what it sounds like: A combination of if and else. It tests the previous condition and then tests a new condition if the previous one was false. A good example is <u>Goldilocks and the Three Bears</u> is if $temperature is greater than 10, print "This porridge is too hot" elseif $temperature is less than 10 print "This porridge is too cold" else print "This porridge is just right!" Only if the first condition isn't already met, it moves on to test the next one. If the next one isn't met, either, the else at the end assumes itself true.

===Switch===

==Loops==

Loops are very similar to conditionals in that they test a condition in order to function, but unlike conditionals instead of continuing with the program, they go back to the start of the block they are in until that condition is no longer true. A loop that is always true, either intentionally or not, is called an <i>infinite loop</i> and will run until the program is stopped, or the loop is escaped. This means to avoid infinite loops, you must change the condition in some way. Generally loops test against variables that are changed inside the loop. $variable++ (The common form for increment, or +1) would be taking a variable and adding one, so if you have a loop that tests your variable to be less than a number (say 10), adding $variable++ would repeat until it's larger (say 10 times from $variable equaling 0) Common loops are ''while'' and ''until''.

===While===

''While'' is very similar to if, generally both in syntax and function. If a condition returns true, it runs the block, and then checks again to see if the block is still true. If it is, it runs it again. This means if you don't do something to change the condition somewhere in the block, it will always be true and run infinitely. 1, since it is not an empty string, false comparative operator, or 0 would always test as true, so while (1) will perform the same action or set of actions over and over.

===Until===

''Until'' is while's polar opposite. It tests for a false value, and runs the loop until the value tests positive. Taking the Goldilocks example again, you could say until a random number between 1 and 20 is 10, print "I'm not eating that!" This would make your program keep testing random numbers until a 10 is reached, at which point you could program what would happen with the best porridge.

==Control Flow==
==Functions==

A function contains code that will be executed whenever the function is "called." A common use is to prevent redundancy in code and keep it organized. Functions accept arguments and can return a value. This allows a function to be dynamic, for example, you might have a function that accepts two numbers and adds them together and returns the result. This might look like (in pseudo code):

<code>
  func add(integer a, integer b){
    return a + b;
  }
  print add(1, 2);
</code>

This code would add the two arguments together (in this case a (= 1) and b (= 2)) then it adds them together and returns the result (3), the return value is then printed.

==Recursion==

==Data Structures==
==Objects==