Pike UppLYSning

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Pike UppLYSning

• nilsson_at_pike.ida.liu.se

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Short History

• LPC
• µLPC
• Cendio
• Roxen IS
• pelab

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Evolved language

• Pragmatic
• Lack of basic features
• Many complex/powerful features
• Skewed feature focus

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Commercially Driven

• Shorter development time
• Failure prevention measures
• Wide platform/system support
• Skewed feature focus

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Focus

• Bitmap graphics
• Text processing
• Network
• Database

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Pike vs. Other Languages

• C
• Java
• LISP
• Python
• C

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Source Code

• du hs 27M
• find . wc -l 2680
• cvs annotate wc -l 610372
• Aprox. Development cost 1 million

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Hello world

• int main(int argc, array argv)
• write(Hello world!\n)
• return 0

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Programming Paradigms

• Imperative
• Functional
• Object Oriented

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Imperative Programming

• Program blocks (if, for, while, case)
• Case fall through
• Labeled breaks
• Symbol scopes (lexical closure)
• x,y

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Functional Programming

• Recursion
• Well defined execution order a x() y() i
  i
• Infix operators are functions (1,2,3)
• x?yz

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OO-programming

• Multiple inheritance
• Named inheritance
• Operator overloading
• Modifiers
• Type comparisons are done according to the
  implements-principle (looks-like).
• All programs are objects

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Hello world, again

• void create()
• write(Hello world!\n)
• exit(0)

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Code environment

• C-like syntax
• White space insensitive
• CPP-like preprocessor
• Version management
• Symbols may use Unicode-characters.

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Coding environment

• Emacs cc-mode font-lock-mode supports Pike.
• Incremental Pike front end (Hilfe)
• Unused unbug

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Datatyper
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float

• IEEE float-simulation
• NaN, Inf
• Special compilation needed for double precision.

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int

• Arithmetic , -, , /,
• Bitwise , , ,
• Logical lt, gt, , lt, gt, !
• 0 is false
• Pike has no maxint.

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string

• string a hello \n \ \007 \x4711 world
• string b Line one and
• line two
• Shared strings
• Character range -0x80000000 0x7fffffff
• Operators , -, , /, , , ,
• Index operators a, a..b

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mapping

• ( a 12,
• b 22,
• c 18 )
• Operators , -, , , , -gt, a
• m_delete, indices, values
• foreach(m string index int value)

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arrays

• Operators , -, , ,
• Index operators a, a..b
• Aggregate operators -gt, ()
• Splice operator _at_

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Array mappings

• map(words, sizeof)
• sizeof(words)
• map(words, , \n)
• words\n
• row1row2

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multiset

• Unordered array
• multiset primes (lt 1, 2, 3, 5, 7, 11 gt)

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Funktions

• int square(int x)
• return xx
• int add(int first, int rest)
• return ( first, _at_rest )

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Programs

• class A
• int a
• void create(int _a)
• a _a
• class A (int a)

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Variabeltyper

• Untyped variables (mixed)
• Simple variable types (int)
• Complex variable types (intfloat)
• Specified variable types (int(0..1))

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Specified types

• object(Stdio.File) Stdio.File
• array(intstring)
• function(int, voidstring void)
• array(mapping(stringint(0..127))float)

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Strict Types

• Strict types (pragma strict_types)
• Runtime type checking (pike rt)
• Soft casts
• int(0..30) y fac(x)
• int(0..30) y int(0..30)fac(x)

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Casts
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Memory Management

• Automatic adaptive
• Reference count
• Advanced GC
• Cyclic references
• Weak references
• Reference creation during destruction

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Optimizations

• Tree optimization
• Strength reduction
• Tail recursion
• Peephole optimization
• Native machine code generation

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Benchmark
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Why?

• Easy to learn (C/Java resemblance)
• Powerful data types
• Competitive speed and functionality
• Bug-suppressing
• UNIX-like abstraction
• clean code

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Why not?

• Non-standard language
• Less support/knowledge/documentation
• Less modules than some bigger languages

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More Information

• pike.ida.liu.se