Regular Expressions

• know what the match operator does; what is the default scalar variable on which it operates?
• know what the dot (.) matches
• what is a character class?  be familiar with the predefined character classes?
• be comfortable with using multipliers to create regexes
• given a regex, be able to tell me what is stored in $&, $`, and $' after it is applied
• know the difference between greedy and lazy evaluation
• what is an anchor? how do we match a pattern only at the beginning or end of a string?  how do we match a pattern only if another pattern appears after it (the second pattern not being matched)?
• have an idea of precedence and the use of parentheses to group patterns
• understand parentheses as memory; how would we match a substring that contains four of the same characters (they could be any character, but they must all be the same)? remember when ${grouping-pattern} vs. \{grouping-pattern} is used
• what does the pattern binding operator do for us?
• how can I replace all occurences of a particular pattern in a string with another pattern using the substitution operator?
• understand that a scalar variable can be interpolated into a string; remember that all regex pattern characters interpolated will work properly
• do not worry about the 'o' option to the matching operator
• do not worry about the quote escape
• know how to split a line into parts using a regex
• know how to glue a line back together using join from a list or array with a delimiter between fields
• basically, be prepared to write some simple regexes and indicate the results of applying certain operations

• what is the naming convention for a filehandle?
• know how to open a file and associate it with a filehandle
• be aware of the different file modes -- especially reading, writing, and appending
• know how to close a file
• be comfortable with handling error conditions using die; know how to print out the most recent operating system error
• be able to write to or read from a file using a filehandle
• know how to rewind back to the beginning of a file using seek

• know how to define a subroutine and how to return a value from it
• know how to pass arguments to a subroutine and be able to make use of @_ in a subroutine
• what is the default "call by" in Perl -- that is, are arguments passed in as aliases or copies?
• be aware that a variable is by default global unless declared with my in a subroutine
• know how to use my to create local variables and simulate "call by value"
• do not worry about semiprivate variables (those created using the keyword local)
• basically, be able to write a subroutine that takes arguments and returns some scalar or list value

• know what use strict; does
• know how to bring a module into a Perl script via use
• the only module you need to know anything about is CGI.pm (see CGI section)

• how do you create a reference to an existing variable?
• know how to create an array reference using the anonymous array composer and how to create a hash reference using the anonymous hash composer
• be able to dereference a reference using $ (don't worry about -> for dereferencing)
• be comfortable with passing a reference as a parameter to a subroutine and be able to dereference it and use its value in the routine
• don't worry about passing references to filehandles

• do not worry about emitting HTML source directly
• you do not have to know how to create a form using HTML
• be able to use param to retrieve data from a form field
• know how to use CGI.pm functions to emit HTML elements and form widgets
• be able to generate and process a form from a single CGI script
• know how to create a CGI query object and to invoke CGI methods using the object
• be comfortable with using named (verbose) calling sequences to generate HTML form widgets
• do not worry about locking files
• do not worry about the Guestbook example from Learning Perl, Chapter 19