Perl QuickStart

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Perl QuickStart
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Why Perl?

• Easy to learn, easy to write, easy to use
• Includes the best features from a dozen other
  languages
• Over 5500 third-party modules
• Supports nearly everything in Code Complete
  except the annoying parts.
• Duct-tapes other systems together

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Anatomy of a Perl script
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Data Types

• SCALAR (Identified with the symbol), holds a
  single number or string
• HASH (Identified with the symbol), similar to
  a MUMPS local, holds many values that are
  accessed by name
• LIST (Identified with the _at_ symbol), holds many
  values accessed by number.

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Variable Gotchas

• hash - hashfoo (NOT hashfoo)
• _at_list - list5 (NOT _at_list5)
• The starting sign represents what you WANT, not
  what the variable IS (what it is is determined by
  the or )
• _at_hashfoo,bar,baz ?
• _at_list hash ?

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Major differences from MUMPS

• Commands not abbreviated
• Variables always marked with prefixes
• Spaces/Lines not significant
• Statements end with the
• Routines/Modules dont know about each other
• Blocks are created with and symbols

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Hello World

• 1.0 - Basic Syntax
• 2.0 - Print any message, followed by reverse
• 3.0 - CGI Greet the user by Name
  CGI-gtuser(name)

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Working with Lists

• Creating lists with _at_list ( )
• Push, Pop, Shift, Unshift, Splice
• Sequential access display anything gt 6
• Foreach
• Count how many start with a given number

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Regular Expressions

• /foo/
• ,
• , , , ?, least,most
• Using () to save pieces
• Revising Starts with 1 to use grep

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Searching VMACS

• Sequentially
• Counting user by type (Status)
• Skipping deactive users (DctvDate and
  DctvDate.time vs time)
• Fetching a particular user
• Finding patients named X

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Questions?

• Future classes
• Helpful features of Perl
• More VMACSModules
• Websites
• www.cpan.org
• plumeria.vmth.ucdavis.edu/info/