Pike UppLYSning

nilsson@pike.ida.liu.se

Short History

LPCµLPCCendioRoxen ISpelab

Evolved language

PragmaticLack of basic featuresMany complex/powerful featuresSkewed feature focus

Commercially Driven

Shorter development timeFailure prevention measuresWide platform/system supportSkewed feature focus

Focus

Bitmap graphicsText processingNetworkDatabase

Pike vs. Other Languages

CJavaLISP

PythonC#

Source Code

du –hs : 27Mfind . | wc -l : 2680cvs annotate | wc -l : 610372Aprox. Development cost: $1 million

Hello world

int main(int argc, array argv)

{

write(“Hello world!\n”);

return 0;

}

Programming Paradigms

ImperativeFunctionalObject Oriented

Imperative Programming

Program blocks (if, for, while, case)Case fall throughLabeled breaksSymbol scopes (lexical closure)x,y;

Functional Programming

RecursionWell defined execution order

a = x() || y(); i = i++;

Infix operators are functions `+(1,2,3)

x?y:z

OO-programming

Multiple inheritanceNamed inheritanceOperator overloadingModifiersType comparisons are done according to

the implements-principle (looks-like).All programs are objects

Hello world, again

void create() {

write(“Hello world!\n”);

exit(0);

}

Code environment

C-like syntaxWhite space insensitiveCPP-like preprocessorVersion managementSymbols may use Unicode-characters.

Coding environment

Emacs cc-mode & font-lock-mode supports Pike.

Incremental Pike front end (Hilfe)Unused unbug

Datatyper

Simpe float, int, string, (type)

Complex array, multiset, mapping

Functional function, program, object

float

IEEE float-simulationNaN, InfSpecial compilation needed for double

precision.

int

Arithmetic: +, -, *, /, %Bitwise: |, &, ^, ~Logical: <, >, ==, <=, >=, !0 is false Pike has no maxint.

string

string a = “hello \n \” \007 \x4711 world”;string b = #”Line one and line two”;

Shared stringsCharacter range -0x80000000 – 0x7fffffffOperators: +, -, *, /, %, |, &, ^Index operators: [a], [a..b]

mapping

([ “a” : 12,

“b” : 22,

“c” : 18 ])

Operators: +, -, |, &, ^, ->, [a]m_delete, indices, valuesforeach(m; string index; int value)

arrays

Operators: +, -, &, |, ^Index operators: [a], [a..b]Aggregate operators: ->, ()Splice operator: @

Array mappings

map(words, sizeof);sizeof(words[*]);

map(words, `+, “\n”);words[*]+”\n”;

row1[*]+row2[*]

multiset

Unordered arraymultiset primes = (< 1, 2, 3, 5, 7, 11 >);

Funktions

int square(int x) {

return x*x;

}

int add(int first, int … rest) {

return `+( first, @rest );

}

Programs

class A {

int a;

void create(int _a) {

a = _a;

}

}

class A (int a) { }

Variabeltyper

Untyped variables (mixed)Simple variable types (int)Complex variable types (int|float)Specified variable types (int(0..1))

Specified types

object(Stdio.File) = Stdio.Filearray(int|string)function(int, void|string : void)array(mapping(string:int(0..127))|float)

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);

Casts

(int)”3” 3

(int)”hej” 0

(int)”010hej” 10

(string)007 “7”

(array(int))({ “1”, “2”, “3” }) ({ 1, 2, 3 })

(array(int))”123” ({ 49, 50, 51 })

Memory Management

Automatic & adaptiveReference countAdvanced GC

Cyclic references Weak references Reference creation during destruction

Optimizations

Tree optimizationStrength reductionTail recursionPeephole optimizationNative machine code generation

Benchmark

Java Perl PHP Pike PythonAckermann 16.7 26.6 57.1 5.0 Boom!

Fibonacci 3.1 8.4 12.6 1.6 7.8Method call 2.3 7.7 2.8 8.3Nested loop 7.5 21.9 74.9 0.9 31.2Object inst. 3.7 21.8 3.9 11.0

Sieve 6.7 14.7 49.5 6.8 22.1String concat 2.8 3.0 4.1 3.2 5.1

Arrays 1.8 6.2 13.0 1.4 6.4Lists 5.8 4.2 2.8 6.1

Why?

Easy to learn (C/Java resemblance)Powerful data typesCompetitive speed and functionalityBug-suppressingUNIX-like abstraction“clean” code

Why not?

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

More Information

pike.ida.liu.se