λ-wiki

λ-wiki :: tutorial

www!k! v.20120610

λ-wiki :: éditeur

_h1 tutorial
_p {u In case of a bad display, please reload the page to actualise the parser.}
_h6 1) primitives
{pre  {@ class:terminal;}
? '{+ 1 2 3 4}' 
 > {+ 1 2 3 4}

? '{+ 1 2 3 -6}' 
 > {+ 1 2 3 -6}

? '{- 1 2 3}' 
 > {- 1 2 3}

? '{sqrt {+ {* 3 3} {* 4 4}}}' 
 > {sqrt {+ {* 3 3} {* 4 4}}}

? '{fact 10}' 
 > {fact 10}
}

_h6 2) constants
{pre  {@ class:terminal;}
? '{PI}'
 > {PI}

? '{E}'
 > {E}
}

_h6 3) booleans
{pre  {@ class:terminal;}
? '{if true then YES else NO}'
 > {if true then YES else NO}

? '{if {lessthen 1 2} then YES else NO}'
 > {if {lessthen 1 2} then YES else NO}

? '{if {equal 1 2} then YES else NO}'
 > {if {equal 1 2} then YES else NO}

? '{if {greaterthen 2 1} then YES else NO}'
 > {if {greaterthen 2 1} then YES else NO}

? '{if {equal {sqrt 4} 2} then YES, {sqrt 4} = 2 else NO}'
 > {if {equal {sqrt 4} 2} then YES, '{sqrt 4}' = 2 else NO}
}
_h6 4) user's functions and vars
{pre  {@ class:terminal;}
? '{define square :x = (* :x :x)}' 
 > {define square :x = (* :x :x)}

? '{inspect_function square}' 
 > {inspect_function square}

? '{square 3}' 
 > {square 3}

? '{square 12}' 
 > {square 12}

? '{define circonference :r = (* 2 (PI) :r)}'
 > {define circonference :r = (* 2 (PI) :r)}

? '{circonference 1}'
 > {circonference 1}

? '{define hypothenuse :a :b = (sqrt (+ (* :a :a) (* :b :b)))}'
 > {define hypothenuse :a :b = (sqrt (+ (* :a :a) (* :b :b)))}

? '{hypothenuse 3 4}'
 > {hypothenuse 3 4}
}

_h6 5) serie, map
{pre  {@ class:terminal;}
? '{serie 1 34}' 
 > {serie 1 34}

? '{map square {serie 1 27}}' 
 > {map square {serie 1 27}}

? '{map sqrt {serie 1 7}}' 
 > {map sqrt {serie 1 7}}

? '{+ {serie 1 1000}}' 
 > {+ {serie 1 1000}}

? '{+ {map square {serie 1 1000}}}' 
 > {+ {map square {serie 1 1000}}}

? '{map fact {serie 1 10}}' 
 > {map fact {serie 1 10}}

? '{map inv {serie 1 10}}' 
 > {map inv {serie 1 9}}

? '{define foo = (map fact (serie 0 10))}' 
 > {define foo = (map fact (serie 0 10))}
? '{foo}' 
 > {foo}
? '{+ 2 {map inv {foo}}}' (why +2 ? some work to do !)
 > {+ 2 {map inv {foo}}} which is not far from euler's number = {E}

}

_h6 6) recursion
{pre  {@ class:terminal;}
? '{define myfact :r :i :n = 
    (if (greaterthen :i :n)
        then :r
        else (myfact (* :r :i) (+ 1 :i) :n)
    )
  }'
 > {define myfact :r :i :n = 
    (if (greaterthen :i :n)
        then :r
        else (myfact (* :r :i) (+ :i 1) :n)
    )
  }

? '{define factorial :n = (1 1 :n)}'
 > {define factorial :n = (myfact 1 1 :n)}

? '{factorial 10}'
 > {factorial 10}
}

_h6 7) inspect functions : html tags, static, dynamic
{pre {@ class:terminal;}
1) {lib html}
2) {lib core}
3) {lib dyn}
}