Cross Ref > Language Basics

Perl is case sensitive.

print "hello"; //This works.

Print "hello"; //This does not.

Access VBA is not case sensitive. Like VB Classic, if you type any other case for command or variable names, Access VBA will change it to the "accepted" or "defined" case. For example, if you type msgbox it is converted to Msgbox.

Syntax Example:   The following code works: MsgBox ("hello")

In Perl, you create the entire HTML page within your .PL script file using print commands.

For Perl, PHP, JavaScript, Java,and C++, I prefer to put the first { at the end of the first line of the code block as in this example because I see morePeal codeformatted that way.

$x = "Yes";

If ($x == "Yes") {
  print "Hello world";

  print "I am a Perl coder.";

}

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

Sub x

End Sub

If x Then

End If

While x

WEnd

Commenting Code
Perl uses # for single line comments and Perl does NOT have a multiple line comment.

Compiler Directives (A special comment.)

Perl also uses compiler directives embedded in comments with #! as in:

#!/usr/local/bin/perl -w

#This is a comment in Perl.

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

Directives - #

Directives are sometimes called compiler or preprocessor directives. A # is used for directives within Access VBA code. Access VBA offers only an #If..then/#ElseIf/#Else directive.

'Single line comment.
 

REM Old school single line comment.
 
#If MyDirective Then
  '...some code.
#End If

 Access VBA Comments (' or REM)

In Perl, you declare constants using the use constant keywords:

use constant CONST_NAME => "Value";

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

use constant FULL_NAME => 'Mike Prestwood';
use constant AGE => 38;

print "Your name is " . FULL_NAME . ".<br>";
print "You are " . AGE . ".<br>";

Scope can be Public, Global, or Private. The use of the newer Public keyword is preferred to the older Global. Private Const is the same as just specifying Const.

Const kPI = 3.1459

Const kName = "Mike"

//Public variable:

Public Const kFeetToMeter=3.28, kMeterToFeet=.3

 Access VBA Constants (Const kPI = 3.1459)

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 " _".

MsgBox "Hello1"
MsgBox "Hello2"
MsgBox "Hello3"

'The following commented code on a single line does not work...
'MsgBox "Hello4"  MsgBox "Hello5"
 
'Two or more lines works too with a space+underscore:
MsgBox _
 "Hello6";

String literals are quoted as in "Prestwood". If you need to embed a quote use a slash in front of the quote as in \".

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).

print "Hello";

print "Hello \"Mike\".";

#Does Perl evaluate this simple

#floating point math correctly? No! 

if ((.1 + .1 + .1) == .3) {
  print("Correct");
} else {
  print("Not correct");
}

 Perl Literals (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 optimized out and replaced with # if only integer values are used.

MsgBox ("Hello")

MsgBox ("Hello ""Mike"".")

'Does Access VBA evaluate this simple

'floating point math correctly? No! 

If (.1 + .1 + .1) = 0.3 Then
  MsgBox "Correct"
Else
  MsgBox "Not correct"
End If

Perl is a loosely typed language with only three types of variables: scalars, arrays, and hashes. Use $ for a scalar variable, @ for an array, or % for a hash (an associative array).

The scalar variable type is used for any type of simple data such as strings, integers, and numbers. In Perl, you identify and use a variable with a $ even within strings.

#!/usr/local/bin/perl -w

 
print("Content-type: text/html\n\n");

$fullname = 'Mike Prestwood';
$Age = 38;
$Weight = 162.4;

 

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

 Perl Variables ($x = 0;)

Access VBA is a loosely typed language. Declaring variables is optional unless you use the Option Explicit statement to force explicit declaration of all variables with Dim, Private, Public, or ReDim. Using Option Explicit is strongly recommended to avoid incorrectly typing an existing variable and to avoid any confusion about variable scope.

Undeclared variables are variants. To specifically declare a variant, use:

Dim x As Variant

Dim x 

Common data types include Byte (0..255), Boolean, Integer (2-byte integers), Long (4-byte integers), Currency, Single (32-bit number), Double (64-bit number), Date, String, and variant.

Variables declared with Dim at the module level are available to all procedures within the module. At the procedure level, variables are available only within the procedure.

Dim FullName As String
Dim Age As Integer
Dim Weight As Double

FullName = "Mike Prestwood"

Age = 32

Weight = 154.4

'Declaritive assignment not supported:

''Dim Married As String = "Y"   '>>>Not supported.

 Access VBA Variables (Dim x as Integer)