Euphoria Programming Language

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Euphoria Programming Language

• CSC 507
• Kasilingam Vimalan

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Euphoria

• End-User Programming with Hierarchical Objects
• for Robust Interpreted Applications
• Created by Robert Craig from Rapid Deployment
  Software
• First released in 1993 for 32-bit DOS
  platform.
• Interpreter is available for Windows, DOS,
  Linux and FreeBSD can
  be downloaded freely form
  http//www.rapideuphoria.com
• Can develop various applications such as
  Windows GUI programs, and Linux X Windows
  programs, CGI programs etc

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• Key Features of Euphoria
• Very simple language
• Interpreted language
• Automatic memory management and garbage
  collection.
• Runtime type checking ( it can be turned off at
  runtime).

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• Two main Data Types
• 1. Atom is a number that can be either 31-bit
  integer or 64-bit floating-point.
• Example
• atom a, b, c, d, e
• a 'B' -- equivalent to the atom 66
• b 0
• c 1000
• d 98.6
• e -1e6

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• 2. sequence
• it a collection of numeric value or atoms
• can have zero or more elements
• each element is either an atom or a sequence
• it can grow dynamically at runtime
• The first element in a sequence has an index of
  one 1
• Example
• sequence a, b, c, d, e, f
• a 2, 3, 5, 7, 11, 13, 17, 19
• b "abcd" - this is actually 97, 98,
  99,100
• c 1, 2, 3, 3, 3, 4, 5, 6
• d "jon", "smith", 52389, 97.25

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• Euphoria has two additional
• specialized data types
• 1. Integer is a special form of atom, restricted
  to 31-bit integer values in the range -1073741824
  to 1073741823.
• 2. Object is a generic data type that can contain
  any of the above, and can be changed during
  run-time

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• Operators
• Arithmetic Operators
• unary-, unary, , /, , -
• Relational Operators
• lt   gt   lt   gt     !
• Note for string use equal() or compare()
• Logical Operators
• and, or, xor, not
• Other operator
• - concatenation operator
• Precedence
• function/type calls

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• Expressions
• In Euphoria one can perform an operation on
  entire sequences of data with one expression.
• Examples
• x 1,2,3 5
• -- x is 6, 7, 8
• x -1, 2, 3, 4, 5
• --x is -1, -2, -3, -4, -5
• x 5, 6, 7, 8 10, 10, 20, 100
• -- x is 15, 16, 27, 108
• w 1, 2, 3, 4, 5 4, 5, 6
  
• -- w is 4, 8, 15, 20, 30

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• Logical Expression
• Example
• 5 and -4 -- 1 (true)
• not 6 -- 0 (false)
• Short-circuit evaluation of and and or takes
  place for if, elsif and while conditions only. It
  is not used in other contexts.
• Examples with logical and relational
• operators
• x 1 or 1,2,3,4,5
• -- x is 1,1,1,1,1
• w 1, 0, 0, 1 and 1, 1, 1, 0
• -- w is 1, 0, 0, 0

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• Subscripting/Slicing of Sequences
• x 5, 7.2, 9, 0.5, 13
• x2 11,22,33
• Then x becomes 5, 11,22,33, 9, 0.5, 13
• y
• 1,1, 3,3, 5,5,
• 0,0, 0,1, 9,1,
• -1,9,1,1, 2,2
• y231 is 9
• Array of strings
• s "Hello", "World", "Euphoria", "",
  "Last One"

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• user-defined types
• type hour(integer x)
• return x gt 0 and x lt 23
• end type
• hour h1, h2
• h1 10 -- ok
• h2 25 -- error! program aborts with a message

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• If statement
• 1. if ltlogical expressiongt then
• ltstatementgt
• end if
• 2. if ltlogical expressiongt then
• ltstatementgt
• else
• ltstatementgt
• end if
• 3. if ltlogical expressiongt then
• ltstatementgt
• elsif ltlogical expressiongt then
• ltstatementgt
• elsif ltlogical expressiongt then

Example if a lt b then x 1 end if
if a 9 then x 4 y 5 else z 8
end if if char 'a' then x 1 elsif char
'b' then x 2 elsif char 'c' then x 3
else x -1 end if
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• for statement
• for ltvariablegt ltstartgt to ltendgt by ltstepgt do
• ltstatementgt
• end for
• Example
• for i 1 to 10 do
• ? i -- ? is a short form for print
• end for
• for i 10.0 to 20.5 by 0.3 do
• for j 20 to 10 by -2 do
• ? i, j
• end for
• end for

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• while statement
• while ltlogical_expressiongt do
• ltstatementgt
• end while
• Example
• i 1
• a hello
• while i lt length(a) do
• ? ai
• i i 1
• end while

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• Subprograms or routines
• There are two types of routines Procedure and
  Function.
• Parameters
• All arguments to routines are always passed by
  value.
• There is no pass-by-reference facility.
• Sequences use copy-on-write semantics.

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• Procedure
• procedure ltprocedure namegt(ltargumentsgt) ltstatem
  entgt
• end procedure
• Example
• procedure plot(integer x, integer y)
  
• position(x, y)
• puts(1, '')
• end procedure
• Note Dose not allows to declare local variable

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• Functions
• Function is very similar to procedure, but it
  returns a value, and can be used in an
  expression.
• function ltfunction namegt (ltargumentsgt)
  
• ltstatementgt
• return ltreturn objectgt
• end function
• function max(atom a, atom b)
• if a gt b then
• return a
• else
• return b
• end if
• end function

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• function swap(sequence list, integer x, integer
  y)
• object tmp
• tmp listx
• listx listy
• listy tmp
• return list
• end function
• procedure permute(sequence list, integer start)
• if start lt length (list) then
• for i start to length(list) do
• permute(swap(list, start, i), start 1)
• end for
• else
• ? list
• end if
• end procedure

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• Short comes
• No object oriented programming support.
• No exception handling.
• No concurrency support.

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• Bibliography
• 1. Euphoria programming language document
  http//www.rapideuphoria.com/manual.htm
• 2. Wikipedia, the free encyclopedia
• http//en.wikipedia.org/wiki/Euphoria_programming
  _language