IT SOLUTIONS
Your full service technology partner! 
-Collapse +Expand
To/From Code
-Collapse +Expand Cross Ref Guide
-Collapse +Expand Members-Only
Sign in to see member-only pages.
   ► KBTo/From GuidesASP Classic  Print This     

ASP Classic and PHP Cross Reference Guide

By Mike Prestwood

ASP Classic versus PHP: A side by side comparison between ASP Classic and PHP.

ASP Classic

Version: This content is based on ASP Classic 3.0 released November 2000. The focus of this content is on server-side scripting.

This content focuses on topics in common among the languages documented here so this content most likely applies to earlier versions.

In addition, much of the ASP syntax presented here is in common with MS Access and VB Classic. Finally, the syntax for VB.Net is based on VB so some of it even applies to VB.Net because ASP is also based on VB.

PHP

Version: This content is based on PHP 5 and tested using our web hosting server farm. The focus of this content is on server-side scripting.

This content focuses on topics in common among the languages documented here so nearly all this syntax applies to most PHP development environments as well as earlier versions of PHP.

Some of PHP's syntax will look similar to Perl but with significant differences.

Note: To be clear, the subject of this information is generic PHP 5 and in some cases Delphi for PHP. Although much of the information applies to other PHP tools, we only verified the syntax and information within generic PHP and/or Delphi for PHP.

 
Tool Basics
 

Developer environment basics such as common file extensions, common keyboard shortcuts, etc.

Deployment Overview

[Other Languages] 
ASP Classic: 

With ASP Classic, you simply copy your files to a web server that is capable of running ASP pages. This includes your .ASP pages along with supporting files such as images, include files, and database files.

Optionally, you can also deploy a global.asa file which is used to code certain events like application start, application end, session start, and session end.

More Info / Comment
PHP: 

With PHP, you simply copy your files to a web server that is capable of running PHP pages.

More Info / Comment




Development Tools

[Other Languages] 

Languages Focus

Primary development tool(s) used to develop and debug code.

ASP Classic: 

Microsoft Visual Interdev was popular for several  years but isn't used as much any more. Any good editor such as Microsoft Expression Web, etc. will work but debugging is left up to interactive skills.

More Info / Comment
PHP: 

Many developers just use a text editor. There are many PHP editors available including phpDesigner, and Delphi for PHP.

More Info / Comment




File Extensions

[Other Languages] 

Languages Focus

Common or primary file extensions used (not a complete list, just the basics).

ASP Classic:   .ASP

.asp is the default extension for Active Server Pages (ASP) although some developers will change the default extension in an effort to add an additional security level. Although there is no clear standard for include files, using .INC is common but you must make sure that .INC files are not executed nor displayed.

More Info / Comment
PHP:   .php

.php is the default extension for PHP although some developers will change the default extension in an effort to add an additional security level. If your code is tied to a particular version of PHP then some developers at the major PHP version number to the extension as in .php3, .php4, .php5, etc. 

.phtml is also sometimes used especially for files that contain both HTML and Perl code.

More Info / Comment




Overview and History

[Other Languages] 
ASP Classic: 

Language Overview: Class-based language. Although you can create classes, ASP is not fully OOP. It is a traditional language with a few OOP extensions. You code in a traditional approach using functions, procedures, and global data, and you can make use of simple classes to help organize your reusable code.

Target Platforms: ASP Classic is most suitable for creating websites targeting any browser (IIS Web Server with ASP Classic installed or equivalent).

More Info / Comment
PHP: 

PHP is a hybrid language with both traditional PHP and OOP features. PHP is widely-used general-purpose scripting language that is especially suited for web development and can be embedded into HTML. PHP has been used to create some amazing web content, particularly outstanding message boards.

Target Platforms: PHP is most suitable for creating websites targeting any browser (any web server with PHP installed).

More Info / Comment




Report Tools Overview

[Other Languages] 

Languages Focus

Built-In: Some development tools have a reporting tool built-in and some do not. For example, typically desktop databases such as Paradox and Access have a built-in reporting tool and typically that reporting tool is used with nearly every application built with it. A built-in reporting tool makes development of reports across many clients and applications consistent and therefore easy.

Add-On: Development tools that do not have a built-in reporting tool need to use either a currently bundled report writer, or one of the popular reporting tools that integrates well with the development tool. For example, popular reporting tools include Crystal Reports, ReportBuilder, and MS SQL Reporting Services (tied to MS SQL).

ASP Classic: 

No built-in report writer but because ASP Classic targets a client browser (a document interfaced GUI), a common solution is to simply output an HTML formatted page with black text and a white background (not much control but it does work for some situations).

More Info / Comment
PHP: 

No built-in report writer but because website development targets a client browser (a document interfaced GUI), a common solution is to simply output an HTML formatted page with black text and a white background (not much control but it does work for some situations).

More Info / Comment




 
Language Basics
 

Language basics is kind of a catch all for absolute beginner stuff. The items (common names) I chose for language basics is a bit random and include items like case sensitivity, commenting, declaring variables, etc.

Case Sensitivity

[Other Languages] 

Languages Focus

Case sensitiviy in this case is referring to commands and variable names. For example, are "printf" and "PrintF" equivalent? Are fullname and FullName equivalent? When you create commands, operations, methods, or variables should you worry about case?

ASP Classic:   No

ASP Classic is not case sensitive. My preference for all languages where case sensitivity does not matter is to use camel caps as in the first example above. Many developers coming from a case sensitive language prefer to use all lowercase.

Syntax Example:  

You can use any of the following:

Response.Write "Hello"
response.write "Hello"
RESPONSE.WRITE "Hello"
REsponse.WritE "Hello"
PHP:   Yes and No

PHP is case sensitive with variable names but not with commands. Although commands are case incenstive, I prefer to use all lowercase because it's easy to type and that's what I see most PHP coders doing and I see it on PHP.Net.

Syntax Example:

All of the following are equivalent:

echo "hello<br>";
ECHO "hello<br>";
Echo "hello<br>";
eCHo "hello<br>";

...but variables are case sensitive:

$fullname = "Mike Prestwood"; //These are two...
$FullName = "Wes Peterson";   //separate varialbes.




Code Blocks

[Other Languages] 

Languages Focus

The rules for code blocks within a language dictate where you can declare variables, how you "bracket" code, etc.

ASP Classic:   End Xxx

In .ASP html pages, you embed ASP code between <% and %>.

ASP Classic code blocks are surrounded by statement ending keywords that all use End such as End Sub, End If, and WEnd.

Syntax Example:
<%
Sub x
End Sub
 
If x Then
End If
 
While x
WEnd
%>
PHP:   { }

In .PHP html pages, you embed PHP code between <?PHP and ?>.

For PHP, JavaScript, Java,and C++, I prefer to put the first { at the end of the first line of the code block as in the example above because I see morePHP codeformatted that way (and on PHP.Net).

PHP Alternative Syntax

Although I don't like to use it, PHP offers an alternative syntax for if, while, for, foreach, and switch. These code blocks are surrounded by statement ending keywords that all use End with camel caps such as endif, endwhile, endfor, endforeach,and endswitch.

Syntax Example:
<?PHP
$x = "Yes";
//Simple if
If ($x == "Yes")
echo "hello world";
 
//If with a block of code.
If ($x == "Yes") {
echo "Hello world";
  echo "I am a PHP coder!";
}
?>




Comments

[Other Languages] 

Languages Focus

Commenting code generally has three purposes: to document your code, for psuedo coding prior to coding, and to embed compiler directives. Most languages support both a single line comment and a multiple line comment. Some languages also use comments to give instructions to the compiler or interpreter.

ASP Classic:   ' or REM

Commenting Code
ASP Classic, like all the VB-based languages, uses a single quote (') or the original class-style basic "REM" (most developers just use a quote). ASP Classic does NOT have a multiple line comment.

Preprocessor Directives - @ and #
An @ is used for preprocessor directives within ASP code (within <% %>) and a # is used for HTML-style preprocessor directives.

Note: ASP Classic does not support VB Classic's #If directive.

Syntax Example:
'Single line comment.
REM Old school single line comment.

 

Common Preprocessor Directives include:

<%@LANGUAGE=VBScript%>
<!-- #Include File="includes.inc" -->
PHP:   # or // or /* ... */

Commenting Code
Use the multi-line to comment out large blocks of code and to write multiple line comments.

Syntax Example:
#This is a comment in PHP.

//This is too!

/*
This is a multi-line
comment.
*/




Constants

[Other Languages] 

General Info: Computer Language Constants

A constant is just like a variable (it holds a value) but, unlike a variable, you cannot change the value of a constant.

ASP Classic:   Const kPI = 3.1459

Scope can be Public or Private. Public Const is the same as just specifying Const. As with variables, all constants are variants. You do not specify the type, it's implied.

Syntax Example:
Const kPI = 3.1459
Const kName = "Mike"
 
//Public variable:
Public Const kFeetToMeter=3.28, kMeterToFeet=.3
PHP:   define

In PHP, you declare constants using the define keyword:

define("CONST_NAME", "Value");

Constants in PHP are case sensitive. A common standard in PHP is to use all-uppercase letters, with underscores to separate words within the name.

Syntax Example:
define('FULL_NAME', 'Mike Prestwood');
define("AGE", 25);
  
echo "Your name is " . FULL_NAME . ".";
echo "You are " . AGE . ".";




End of Statement

[Other Languages] 

Languages Focus

In coding languages, common End of statement specifiers include a semicolon and return (others exist too). Also of concern when studying a language is can you put two statements on a single code line and can you break a single statement into two or more code lines.

ASP Classic:   Return

A return marks the end of a statement and you cannot combine statements on a single line of code. You can break a single statement into two or more code lines by using a space and underscore " _".

Syntax Example:
Response.Write("Hello1")
Response.Write("Hello2")
Response.Write("Hello3")

'The following commented code on a single line does not work...
' Response.Write("Hello4") Response.Write("Hello5")

'Two or more lines works too with a space+underscore:
Response.Write _
("Hello6")
PHP:   ;
Syntax Example:
echo "Hello";




Literals

[Other Languages] 

General Info: Programming Literals

A value directly written into the source code of a computer program (as opposed to an identifier like a variable or constant). Literals cannot be changed. Common types of literals include string literals, floating point literals, integer literals, and hexidemal literals. Literal strings are usually either quoted (") or use an apostrophe (') which is often referred to as a single quote. Sometimes quotes are inaccurately referred to as double quotes.

Languages Focus

In addition to understanding whether to use a quote or apostrophe for string literals, you also want to know how to specify and work with other types of literals including floating point literals. Some compilers allow leading and trailing decimals (.1 + .1), while some require a leading or trailing 0 as in (0.1 + 0.1). Also, because floating point literals are difficult for compilers to represent accurately, you need to understand how the compiler handles them and how to use rounding and trimming commands correctly for the nature of the project your are coding.

ASP Classic:   quote

String literals are quoted as in "Prestwood". If you need to embed a quote use two quotes in a row.

To specify a floating point literal between 1 and -1, you can preceed the decimal with a 0 or not (both work). In other words, preceding and following decimals are allowed (both .1 and 0.1). Trailing decimals are also allowed (1, 1., and 1.0 are all equivalent and allowed).

Syntax Example:
Response.Write "Hello"
Response.Write "Hello ""Mike""."
  
'Does ASP evaluate this simple
'floating point math correctly? No! 
If (.1 + .1 + .1) = .3 Then
 Response.Write "Correct"
Else
 Response.Write "Not correct"
End If
PHP:   quote or apostrophe

In PHP you can use quotes, or apostrophes as in "Prestwood", and 'Prestwood' for string literals. Use a slash in front of a quote or apostrophe to embed same type as in \' and \".

To specify a floating point literal between 1 and -1, you can preceed the decimal with a 0 or not (both work). In other words, preceding and following decimals are allowed (both .1 and 0.1). Trailing decimals are also allowed (1, 1., and 1.0 are all equivalent and allowed).

Syntax Example:
echo "Mike's drums are over there.<br>";
echo 'Mike said, "hi!"<br>';
  
//Does PHP evaluate this simple
//floating point math correctly? No! 
If ((.1 + .1 + .1) == .3) {
 Echo "Correct";
} Else {
 Echo "Not correct";
}




Variables

[Other Languages] 

Languages Focus

A variable holds a value that you can use and change throughout your code so long as the variable is within scope. With variable declaration, you not only want to know the syntax of how you declare a variable but you also want to know where. Are you allowed to declare a variable inline? What are the available scopes: local vs. global. Can you assign a value at the same time you declare a variable?

ASP Classic:   Dim x

ASP Classic is a loosely typed language. No variable types in ASP (all variables are variants). Declaring variables is even optional unless you use the Option Explicit statement to force explicit declaration of all variables with Dim in that script. Using Option Explicit is strongly recommended to avoid incorrectly typing an existing variable and to avoid any confusion about variable scope.

For example, at the top of my common include file, I have the following:

<%@LANGUAGE=VBScript%>
<%
Option Explicit
'...more code here.
%>
Syntax Example:
Dim Fullname
Dim Age
Dim Weight
 
FullName = "Mike Prestwood"
Age = 32
Weight = 154.4
 
'Declaritive assignment not supported:
''Dim Married = "Y"   '>>>Not supported.
PHP:   $x = 0;

PHP is a loosely typed language. No variable types in PHP. Declaring and using variables are a bit different than in other languages. In PHP, you identify and use a variable with a $ even within strings!

You assign by reference with & as in &$MyVar.

Syntax Example:
$fullname = 'Mike Prestwood';
$FullName = 'Wes Peterson'; //This is a different variable!
$Age = 38;
$Weight = 162.4;
 

echo "Your name is $fullname.
";
echo "You are $Age and weigh $Weight.
";




 
Language Details
 

Language Details is kind of a catch all for stuff that didn't make it into language basics nor any other category.

Custom Routines

[Other Languages] 

Languages Focus

For non-OOP languages, a custom routine is a function, procedure, or subroutine and for pure OOP languages, a custom routine is a class method. Hybrid languages (both non-OOP and OOP) combine both.

ASP Classic:   Sub, Function

ASP Classic is a non-OOP language with some OOP features. It offers both Subs and Functions. A Sub does not return a value while a Function does. When Subs and Functions are used in a defined class, they become the methods of the class.

Syntax Example:
Sub SayHello(ByVal pName)
  Response.Write "Hello " + pName + "!<br>"
End Sub
 
Function Add(ByRef pN1, ByRef pN2)
  Add = pN1 + pN2
End Function
PHP:  "Custom Function" function

PHP uses functions and loosely typed parameters. Function definitions can come before or after their usage so my preference when mixing PHP in with a mostly HTML page is to put the functions after the </html> tag.

Syntax Example:
function sayHello($pName) {
 echo "Hello " . $pName . "<br>";
}
 
function add($p1, $p2) {
 return $p1 + $p2;
}




Inline Code

[Other Languages] 

Languages Focus

Also known as embedded code where you embed another syntax language within the native code of the development environment you are using. The inline code can be compiled by the current development's compiler or by an external compiler.

Do not confuse with inlining which is a coding technique where custom routines are moved inline where the code is executed either by you, by a compiler directive, or automatically by the compiler.

ASP Classic:   Not Supported
[Not specified yet. Coming...]




Inlining

[Other Languages] 

General Info: Inline Routines

Instead of calling a routine, you move the code from the routine itself and expand it in place of the call. In addition to manual inlining, some languages support automatic inlining where the compiler or some other pre-compiler decides when to inline a code routine. Also, some languages allow for developer defined inlining where the developer can suggest and/or force the inlining of a code routine. Inlining can optimize your code for speed by saving a call and return, and parameter management.

Languages Focus

Does it support inlining? If so, does it support developer defined inlining? Does it support automatic inlining? Both?

ASP Classic:   Not Supported
[Not specified yet. Coming...]




Overloading

[Other Languages] 

Types of overloading include method overloading and operator overloading.

Method Overloading is where different functions with the same name are invoked based on the data types of the parameters passed or the number of parameters. Method overloading is a type of polymorphism and is also known as Parametric Polymorphism.

Operater Overloading allows an operator to behave differently based on the types of values used. For example, in some languages the + operator is used both to add numbers and to concatenate strings. Custom operator overloading is sometimes referred to as ad-hoc polymorphism.

ASP Classic:   Not Supported

ASP Classic does not support any type of overloading.

  • Operator - No.
  • Method - No.

Some developers like to pass in an array and then handle the array for a pseudo technique. Although not overloading, it's useful.

PHP: 

PHP

  • Operator - No.
  • Method -
Syntax Example:

 





Parameters

[Other Languages] 
ASP Classic:   ByRef, ByVal

By Reference or Value
For parameters, you can optionally specify ByVal or ByRef. ByRef is the default if you don't specify.

Syntax Example:  
Function SomeRoutine(ByRef pPerson, ByVal pName, Age)
[Not specified yet. Coming...]




Self Keyword

[Other Languages] 
ASP Classic:   me

Same as VB. The Me keyword is a built-in variable that refers to the class where the code is executing.

Syntax Example:
Class Cyborg
 Public CyborgName
 
 Public Function IntroduceYourself() 
  'Using Me. Prints Cameron.
  Response.Write("Hi, my name is " & Me.CyborgName & ".")
  
  'The above is just a demo. You could also not include "Me." 
  'in this case because we are in context of Me now. Using Me 
  'makes more sense when you start to pass Me as a parameter 
  'to a method.
 End Function 
End Class
[Not specified yet. Coming...]




 
Data Structures
 

Data structures allow you to store and work with data. Common data structures include arrays, associative arrays, etc.

Array

[Other Languages] 

Languages Focus

A data structure in which individual values (called elements or items) may be located by reference to one or more integer index variables, the number of such indices being the number of dimensions in the array.

Arrays can start with an index value of 0 or 1, sometimes referred to as 0 based or 1 based.

ASP Classic:   x = Array()

Arrays in ASP Classic use a 0-based indice.

Use UBound to get the number of elements. UBound returns -1 if the array has no elements, 0 if it has 1, 1 if it has 2, etc.

Syntax Example:  
Dim MyArray, i
 
MyArray = Array("Mike", "Lisa", "Felicia", "Nathan")
 
If UBound(MyArray) > -1 Then
  For i = 0 to UBound(MyArray)
    Response.Write MyArray(i)
  Next
End If
[Not specified yet. Coming...]




Associative Array

[Other Languages] 
A set of unique keys linked to a set of values. Each unique key is associated with a value. Think of it as a two column table. MyArray['CA'] = 'California' MyArray['AR'] = 'Arizona'

Languages Focus

Associative arrays are also known as a dictionary or a hash table in other languages.

ASP Classic:   Scripting.Dictionary

Use the scriptiing dictionary object which is available on later versions of ASP Classic (all still commonly in use).

Note: Both Access VBA and VB Classic use a collection for this but collections are not supported in ASP Classic.

Syntax Example:
Dim StateList
 
set StateList = Server.CreateObject("Scripting.Dictionary")
StateList.Add "CA", "California"
StateList.Add "NV", "Nevada"
 
Response.Write "I live in " & StateList.Item("CA")
PHP: 

Declare associative array with initial known values. You can also add to associative array. (You can just assign values without ever declaring it too!)

Syntax Example:
$prices = array( 'Tires'=>100, 'Spark Plugs'=>4 );
$prices['Oil'] = 10;
 
echo "Tires=" . $prices['Tires'] . "<br>";
echo "Oil=" . $prices['Oil'] . "<br>";




Pointers

[Other Languages] 

General Info: Pointers / References

A pointer is a variable type that allows you to refer indirectly to another object. Instead of holding data, a pointer holds the address to data -- the address of another variable or object. You can change the address value a pointer points to thus changing the variable or object the pointer is pointing to.

A reference is a type of pointer that cannot change and it must always point to a valid storage (no nulls).

ASP Classic:   Not Supported

ASP Classic does not offer developer defined pointers.

PHP:   Not Supported

PHP supports references which allow you to refer to the value of a variable but PHP does not support true developer defined pointers. You cannot get and use the address of a variable.

However, you can still do inexpensive assignments by assigning by reference.





 
Statements
 

Common statements such as if statements, loops, etc.

Exception Trapping

[Other Languages] 

Languages Focus

A common usage of exception handling is to obtain and use resources in a "try-it" block, deal with any exceptions in an "exceptions" block, and release the resources in some kind of "final" block which executes whether or not any exceptions are trapped.

ASP Classic:   On Error
Syntax Example:
On Error Resume Next
Response.Write FormatDateTime(f_CurrentActualDate, vbShortDate)
  
  If ErrNumber <> 0 Then
Break(f_CurrentActualDate)
End If
On Error Goto 0
[Not specified yet. Coming...]




If Statement

[Other Languages] 
ASP Classic:   If..ElseIf..Else..End If

The End If is optional if you put your code on a single line.

Syntax Example:
//Single line example.
If X = True Then Response.Write "hello" 
  
//Complete example.
If X = True Then
  '>>>do something.
ElseIf Y = "ABC" Then
  '>>>do something.
Else
  '>>>do something.
End If
PHP:   if..elseif..else

The PHP if statement consists of using if, elseif, and else.

Syntax Example:
$x = 8;
  
if ($x == 10) {
 echo "x is 10."; 
} elseif ($x < 10) {
 echo "x is less than 10.";
} else {
 echo "x must be greater than 10."; 
};




 
Operators
 

A language symbol used for assignment, comparison, computational, or as a logical.

Assignment

[Other Languages] 

Languages Focus

Common assignment operators for languages include =, ==, and :=. An assignment operator allows you to assign a value to a variable. The value can be a literal value like "Mike" or 42 or the value stored in another variable or returned by a function.

ASP Classic:   =

ASP Classic uses = for it's assignment operator.

Syntax Example:
FullName = "Randy Spitz"
Age = 38
PHP:   =

PHP uses = for it's assignment operator.

Syntax Example:
$fullname = "Randy Spitz";
$age = 38;




Comparison Operators

[Other Languages] 

General Info: Round Floating Point Numbers

When comparing floating point numbers, make sure you round to an acceptable level of rounding for the type of application you are using.

Languages Focus

A comparison operator compares two values either literals as in "Hello" and 3 or variables as in X and Counter. Most languages use the same operators for comparing both numbers and strings. Perl, for example, uses separate sets of comparison operators for numbers and strings.

ASP Classic:   =, <>

Save as VB Classic. Common comparison operators:

= equal
<> not equal
< less than
> greater than
<= less than or equal
>= greater than or equal
Syntax Example:
//Does ASP evaluate the math correctly? No!
If .1 + .1 + .1 = .3 Then
Response.Write "correct"
Else
Response.Write "not correct"
End If
PHP:   ==, != or <>

Common comparison operators:

== equal
!= or <> not equal
< less than
> greater than
<= less than or equal
>= greater than or equal

PHP 4 and above also offers === for indentical (equal plus same type) and !== for not identical (not equal or not same type).

Syntax Example:
//Does PHP evaluate the math correctly? No!
if (.1 + .1 + .1 == .3) {
echo "correct";
}
else {
echo "not correct";
}




Empty String Check

[Other Languages] 

Languages Focus

An empty string is a zero length string, a string that is equal to null (""), or not assigned. In some languages, you can check if a string is empty by comparing it to an empty string (""). Some languages distinguish between nil and null ("") so checking if the length is 0 is easier.

ASP Classic:   Len(s&vbNullString)

In ASP Classic, you have to add an empty string to the value being compared in order to get consistent results. For example, add &"" to your string varilable or it's code equivalent &vbNullString. Then compare to an empty string or verify it's length to 0 with Len.

Syntax Example:

All these will work for variables unassigned, set to "", or set to Null:

If s&"" = "" Then
  Response.Write("<br>Quotes with &'' say null is empty")
End If
 
If Len(s&"") = 0 Then
  Response.Write("<br>Len with &'' says null is empty")
End If
 
If Len(s&vbNullString) = 0 Then
  Response.Write("<br>Using vbNullString also works!")
End If
[Not specified yet. Coming...]




Logical Operators

[Other Languages] 

Languages Focus

Logical operators perform conditional and, or, and not operations. Some languages support both binary logical operators that link two and unary logical operators negate (make opposite) the truth value of its argument. Finally, some languages short circuit logic. For example, with this or that, if this is an expression returning true, then that is never executed.

ASP Classic:   and, or, not

Same as VB. ASP Classic logical operators:

and and, as in this and that
or or, as in this or that
Not Not, as in Not This

ASP Classic never short circuits. Given the expression this or that as well as this and that, if this evaluates to false, then that is still executed.

Syntax Example:
'Given expressions a, b, c, and d:
If Not (a and b) and (c or d) Then
  'Do something.
End If
PHP:   and, &&, or, ||, !, Xor

PHP logical operators:

and, && and, as in this and that
or, || or, as in this or that
! Not, as in Not This
Xor either or, as in this or that but not both

Syntax Example:
#Given expressions a, b, c, and d:
if !((a && b) && (c || d)) {
  #Do something.
};




String Concatenation

[Other Languages] 
ASP Classic:  "String Concatenation" & or +

Although you can use either a & or a + to concatenate values, my preference is to use a + because more languages use it. However, if you use & then some type conversions are done for you. If you use + you will sometimes have to cast a value to concatenate it. For example, you will have to use CStr to cast a number to a string if you use the + operator as a concatenation operator.

Syntax Example:
Dim FirstName
Dim LastName
 
FirstName  = "Mike"
LastName  = "Prestwood"
 
Response.Write "Full name: " & FirstName & " " + LastName
 
Response.Write "2+2=" + CStr(2+2)
PHP:  "String Concatenation" .

PHP uses a period (.) known as a dot to concatenate strings.

Syntax Example:
$fname = "Mike";
$lname = "Prestwood";

$fullname = $fname . $lname . "
";

echo "My name is " . "Mike.
";




Unary Operators

[Other Languages] 

General Info: Unary Operator

An operation with only one operand (a single input). Common unary operators include + plus, - minus, and bitwise not. Some operators can function as both unary and binary operators. For example, + and - operators can serve as either.

Languages Focus

What unary operators are supported in additoin to the standard plus, minus, and bitwise not.

ASP Classic: 

An operation with only one operand (a single input) such as +, -, and Not.

PHP: 

A unary operator operates on only one value.

PHP Examples:

  • ! negation operator
  • ++ increment operator
  • -- decrement operator




 
Commands
 

Common commands (procedures and functions). A function returns a value. Optionally, it may also perform an action prior to returning a value. A procedure does not return a value or it returns void or null.

Left of String

[Other Languages] 
ASP Classic:   Left
Syntax Example:
Dim LeftString
LeftString = Left("Prestwood", 3)
Response.Write LeftString
[Not specified yet. Coming...]




 
Database
 

This category documents connecting and using data including database commands, and common technologies used.

Edit Record

[Other Languages] 

Languages Focus

This common syntax name documents editing a record as a whole: add/insert, edit, post data, and delete.

ASP Classic:   AddNew, Update, Delete

In ASP, using ADO, you use RecordSet.AddNew to add a new record, Recordset.Update to post the record, and RecordSet.Delete to delete it. To edit a record, you open the RecordSet using an editable cursor.

Syntax Example:

The following code snippet adds a record to a given editable RecordSet with FullName and Created fields:

objRS.AddNew
objRS.Fields("FullName") = "Barack Obama"
objRS.Fields("Created")  = Now
objRS.Update
[Not specified yet. Coming...]




Filter Records

[Other Languages] 
ASP Classic:   Filter

In ASP, using ADO, you filter a set of records using the Filter property.

Syntax Example:
objRecordSet.Filter = "ExtEmpType='P'"
[Not specified yet. Coming...]




Find Record

[Other Languages] 

Languages Focus

Finding a record is about moving a cursor to a specific record within a set of records (documented here). In addition to finding a record, you can sort, filter, and loop a set of records (documented in their topics).

ASP Classic:   Find, Seek

In ASP, using ADO, you use Find and Seek to move a cursor of a RecordSet to a matching record.

Syntax Example:

Given a valid ADO recordset, the following code snippet finds a specific user and prints out their age:

TC.Find " UserID='mprestwood' "
Response.Write TC.Fields("Age")
[Not specified yet. Coming...]




Record Movement

[Other Languages] 

Languages Focus

Top, bottom, next, and previous.

ASP Classic:   MoveFirst, MoveLast, MoveNext

ASP uses MoveFirst, MoveLast, MoveNext, and MovePrevious to move a database cursor (a RecordSet).

objRecordSet.MoveNext
Syntax Example:

The following snippet moves to the second to last record of a given RecordSet object:

objRecordSet.MoveLast
objRecordSet.MovePrevious
[Not specified yet. Coming...]




Sort Records

[Other Languages] 
ASP Classic:   Sort

In ASP, using ADO, you sort a set of records using the Sort property.

Syntax Example:
objMembersRS.Sort = "FirstName"
[Not specified yet. Coming...]




 
OOP Basics
 

Some languages support object-based concepts such as Paradox, Access, and VB Classic. Other languages have OO extensions and fully support object orientation in a hybrid fashion (such as C++ and Dephi for Win32). Finally, some lanages such as C#, VB.Net, Prism, and Java are entirely written in OO. Meaning, every line of code written must occur within a class).

Base Class

[Other Languages] 

Languages Focus

When you create a class, it is either a base class or inherits from another class. Some languages require all classes to inherit from a common base class and some do not.

ASP Classic:   Not Supported
[Not specified yet. Coming...]




Class..Object

[Other Languages] 

Languages Focus

In short, a class is a data type, and an object is an instance of a class type. A class has methods (routines), properties (member variables), and a constructor. The current values of the properties is the current state of the object. The UML is one of the diagraming disciplines that allows you to document the various changing states of a series of objects.

ASP Classic:   Class..Set..New

Ultra-primitive (no inheritance) but useful and encourages you to think and design using objects. Unlike VB, you can have more than one class per file.

Classes in ASP do support member fields, properties, and methods.

Syntax Example:
'Declare class.
Class Cyborg
  Public Function IntroduceYourself() 
    Response.Write("Hi, I do not have a name yet.") 
  End Function 
End Class
 
'Create object from class.
Set T1 = new Cyborg
T1.IntroduceYourself() 
Set T1 = Nothing      'Be sure to clean up!
[Not specified yet. Coming...]




Inheritance

[Other Languages] 

The concept of a class makes it possible to define subclasses that share some or all of the main class characteristics. This is called inheritance. Inheritance also allows you to reuse code more efficiently. In a class tree, inheritance is used to design classes vertically. (You can use Interfaces to design classes horizontally within a class tree.) With inheritance, you are defining an "is-a" relationship (i.e. a chow is-a dog). Analysts using UML call this generalization where you generalize specific classes into general parent classes.

ASP Classic:   Not Supported
[Not specified yet. Coming...]




Member Field

[Other Languages] 

Also known as a Class Field.

A class variable defined with a specific class visibility, usually private visibility. A member property is different than a member field. A member property uses a member field to store values through accessor methods (getters and setters). For example, it is common to use a private member field to store the current value of a property. The current values of all the class member fields is the current state of the object.

Languages Focus

What modifiers apply to member fields, if any? Typical member field modifiers include scope modifiers (private, protected, etc.) and read-only. Can you initialize the value of a member field when declared ensuring a default value?

ASP Classic: 

ASP Classic does support member fields, but, as usual, you cannot initialize the type nor value of a member field. The type is implied by usage.

Syntax Example:
Class Cyborg
  Private FSerialNumber
  
  Public FCyborgName
  Public FCyborgAge 
Public FSeriesID
End Class
[Not specified yet. Coming...]




Member Method

[Other Languages] 

Also known as a Class Method.

A code routine that belongs to the class or an object instance (an instance of the class). Methods that belong to the class are called class methods or static methods. Methods that belong to an object instance are called instance methods, or simply methods.

When a method returns a value, it is a function method. When no value is returned (or void), it is a procedure method.

Methods frequently use method parameters to transfer data. When one object instance calls another object instance using a method with parameters, you call that messaging.

ASP Classic:   Sub, Function

ASP classic uses the keywords sub and function. A sub does not return a value and a function does. Many programmers like to use the optional call keyword when calling a sub to indicate the call is to a procedure.

Syntax Example:
'Declare class.
Class Cyborg
  Public Function IntroduceYourself() 
    Response.Write("Hi, I do not have a name yet.") 
  End Function 
End Class
 
'Create object from class.
Set T1 = new Cyborg
T1.IntroduceYourself() 
[Not specified yet. Coming...]




Member Modifier

[Other Languages] 

Languages Focus

Traditional private, protected, public, etc. member modifiers are documented under the member visibility topic of the Cross Reference Encyclopedia. With member modifiers here, we address additional member modifiers such as method and field modifiers.

ASP Classic:  "Member Modifiers" Default

Other than visibility modifiers Public and Private, the only other member modifier available in ASP Classic is Default which is used only with the Public keyword in a class block. It indicates that the sub, function, or property is the default method for the class. You can have only one Default per class.

More Info / Comment
[Not specified yet. Coming...]




Member Property

[Other Languages] 
ASP Classic:   Property..Get..Let

ASP classic uses the property keyword and special Get and Let methods to both get and set the values of properties.

Syntax Example:
Class Cyborg
 Private FCyborgName
 
 Public Property Get CyborgName()
  CyborgName = FCyborgName
 End Property
 
 Public Property Let CyborgName(pCyborgName)
  FCyborgName = pCyborgName
 End Property
End Class
[Not specified yet. Coming...]




Member Visibility

[Other Languages] 

General Info: Class Visibility Specifiers

In OOP languages, members of a class have a specific scope that indicates visibility. Standard visibility includes private, protected, and public. Private members are usable by the defining class only (fully encapsulated). They are invisible outside of the class except by friendly classes. Protected members are usable by the defining class and descendant classes only (plus friendly classes). Public members are usable wherever its class can be referenced.

Languages Focus

Traditional member visibility specifiers for fully OOP languages are private, protected, and public. Many modern OOP languages implement additional member visibilities.

Additional member modifiers are documented under the Member Modifiers topic.

ASP Classic:   Private, Public

The member visibility modifiers are Private and Public. If not specified, the default is Public. Private and Public have the usual meaning. Private members are visible only within the class block. Public members are visible within the class and outside of the class.

Syntax Example:
Class Cyborg
  Private FSerialNumber  
  Public FCyborgName
  
  Public Function IntroduceYourself() 
Response.Write("Hi, I do not have a name yet.")
End Function
End Class
[Not specified yet. Coming...]




 
OOP Details
 

More object oriented (OO) stuff.

Abstraction

[Other Languages] 

General Info: Abstract Class / Abstract Member

An abstract class member is a member that is specified in a class but not implemented. Classes that inherit from the class will have to implement the abstract member. Abstract members are a technique for ensuring a common interface with descendant classes. An abstract class is a class you cannot instantiate. A pure abstract class is a class with only abstract members.

Languages Focus

Abstraction is supported at various levels with each language. A language could enforce abstraction at the class level (either enforcing a no-instantiation rule or a only abstract members rule), and with class members (member methods and/or properties).

ASP Classic:   Not Supported
[Not specified yet. Coming...]




Class Helper

[Other Languages] 

A. In Dephi, class helpers allow you to extend a class without using inheritance. With a class helper, you do not have to create and use a new class descending from a class but instead you enhance the class directly and continue using it as you always have (even just with the DCU).

B. In general terms, developers sometimes use the term to refer to any class that helps out another class.

ASP Classic:  "Class Helpers" Not Supported
[Not specified yet. Coming...]




Code Contract

[Other Languages] 

A.k.a. Class Contract and Design by Contracts.

A contract with a method that must be true upon calling (pre) or exiting (post). A pre-condition contract must be true when the method is called. A post-condition contract must be true when exiting. If either are not true, an error is raised. For example, you can use code contracts to check for the validity of input parameters, and results

An invariant is also a code contract which validates the state of the object required by the method.

ASP Classic:  "Code Contracts" Not Supported
[Not specified yet. Coming...]




Constructor

[Other Languages] 

General Info: Class Constructor

Constructors are called when you instantiate an object from a class. This is where you can initialize variables and put code you wish executed each time the class is created. When you initially set the member fields and properties of an object, you are initializing the state of the object. The state of an object is the values of all it's member fields and properties at a given time.

Languages Focus

What is the syntax? Can you overload constructors? Is a special method name reserved for constructors?

ASP Classic:  "Constructors" Class_Initialize

When an object instance is created from a class, ASP calls a special parameter-less sub named Class_Initialize. Since you cannot specify parameters for this sub, you also cannot overload it.

When a class is destroyed, ASP calls a special sub called Class_Terminate.

Syntax Example:
Class Cyborg
  Public CyborgName
 
 Public Sub Class_Initialize
   Response.Write "<br>Class created"
   CyborgName = "Cameron"
  End Sub 
End Class
[Not specified yet. Coming...]




Destructor

[Other Languages] 

General Info: Class Destructor

A special class method called when an object instance of a class is destroyed. With some languages they are called when the object instance goes out of scope, with some languages you specifically have to call the destructor in code to destroy the object, and others use a garbage collector to dispose of object instances at specific times.

Desctructors are commonly used to free the object instance but with languages that have a garbage collector object instances are disposed of when appropriate. Either way, destructors or their equivalent are commonly used to free up resources allocated in the class constructor.

Languages Focus

Are object instances freed with a garbage collector? Or, do you have to destroy object instances.

ASP Classic:   Class_Terminate

When an object instance is destroyed, ASP calls a special parameter-less sub named Class_Terminate. For example, when the variable falls out of scope. Since you cannot specify parameters for this sub, you also cannot overload it.

To explicitly destroy an object, use Set YourClass = nothing. If the Class object is explicitly destroyed, the client returns with the script engine error details.

When an object instance is created from a class, ASP calls a special sub called Class_Initialize.

Syntax Example:
Class Cyborg
  Public Sub Class_Terminate
    Response.Write "<br>Class destroyed"
End Sub
End Class
[Not specified yet. Coming...]




Inheritance-Multiple

[Other Languages] 
ASP Classic:   Not Supported
[Not specified yet. Coming...]




Interface

[Other Languages] 

An element of coding where you define a common set of properties and methods for use with the design of two or more classes.

Both interfaces and abstract classes are types of abstraction. With interfaces, like abstract classes, you cannot provide any implementation. However, unlike abstract classes, interfaces are not based on inheritance. You can apply an Interface to any class in your class tree. In a real sense, interfaces are a technique for designing horizontally in a class hierarchy (as opposed to inheritance where you design vertically). Using interfaces in your class design allows your system to evolve without breaking existing code.

ASP Classic:  "Interfaces" Not Supported

Although ASP Classic does support simple classes, it does not support interfaces.

[Not specified yet. Coming...]




Overriding

[Other Languages] 

General Info: Method Overriding

Where you define or implement a virtual method in a parent class and then replace it in a descendant class.

When you decide to declare a method as virtual, you are giving permission to derived classes to extend and override the method with their own implementation. You can have the extended method call the parent method's code too.

In most OO languages you can also choose to hide a parent method. When you introduce a new implementation of the same named method with the same signature without overriding, you are hiding the parent method.

ASP Classic:   Not Supported

Since ASP Classic does not support inheritance, there is no concept of a descendant class nor overriding.

[Not specified yet. Coming...]




Partial Class

[Other Languages] 

A partial class, or partial type, is a class that can be split into two or more source code files and/or two or more locations within the same source file. Each partial class is known as a class part or just a part. Logically, partial classes do not make any difference to the compiler. The compiler puts the class together at compile time and treats the final class or type as a single entity exactly the same as if all the source code was in a single location.

Languages Focus

For languages that have implemented partial classes, you need to know usage details and restrictions. Can you split a class into two or more files? Can you split a class within a source code file into two or more locations? What are the details of inheritance? Does it apply to interfaces as well?

ASP Classic:  "Partial Classes" Not Supported
[Not specified yet. Coming...]




Prevent Derivation

[Other Languages] 

Languages Focus

How do you prevent another class from inheriting and/or prevent a class from overriding a member.

ASP Classic:   Not Supported
[Not specified yet. Coming...]




Static Member

[Other Languages] 

General Info: Static Class / Static Member

A static member is a member you can have access to without instantiating the class into an object. For example, you can read and write static properties and call static methods without ever creating the class. Static members are also called class members (class methods, class properties, etc.) since they belong to the class and not to a specific object. A static class is a class that contains only static members. In the UML, these classes are described as utility classes.

Languages Focus

Languages that support static members usually at least support static member fields (the data). Some languages also support static methods, properties, etc. in which case the class member is held in memory at one location and shared with all objects. Finally, some languages support static classes which usually means the compiler will make sure a static class contains only static members.

ASP Classic:  "Static Members" Not Supported

Although ASP Classic supports the creation of simple classes, it does not support static methods.

[Not specified yet. Coming...]




Sales Website: www.prestwood.com Or visit our legacy sales site: 
legacy.prestwood.com


©1995-2024 Prestwood IT Solutions.   [Security & Privacy]