Monkey Programming Language

Table of Contents

Summary

//Declare annotation class//Note: In the body, you must use property, not method.class@MinMaxValidator{  property MinLength  property MaxLength default10 //Same as 'property MaxLength = 10'}//This is a marker annotationclass@NoSpaceValidator{}class@DepartmentValidator{  property Department}//The 'Request' classclass Request{@MinMaxValidator(MinLength=1)  property FirstName; //getter and setter are implicit. It is equal to 'property FirstName { get; set; }'@NoSpaceValidator  property LastName;@DepartmentValidator(Department=["Department of Education","Department of Labors"])  property Dept;}//This class is responsible for processing the annotation.class RequestHandler{static fn handle(o){    props= o.getProperties()forpin props{      annos= p.getAnnotations()forannoin annos{if anno.instanceOf(MinMaxValidator){          //p.value is the property real value.iflen(p.value)> anno.MaxLength ||len(p.value)< anno.MinLength{printf("Property '%s' is not valid!\n", p.name)}} elseif anno.instanceOf(NoSpaceValidator){forcin p.value{if c=="" || c=="\t"{printf("Property '%s' is not valid!\n", p.name)break}}} elseif anno.instanceOf(DepartmentValidator){          found=falsefordin anno.Department{if p.value== d{              found=true}}if !found{printf("Property '%s' is not valid!\n", p.name)}}}}}}class RequestMain{static fn main(){    request=new Request()    request.FirstName="Haifeng123456789"    request.LastName="Huang"    request.Dept="Department of Labors"RequestHandler.handle(request)}}RequestMain.main()

Property 'FirstName' not valid!Property 'LastName' not valid!

Overview

Installation

Basic use

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monkey path/to/file

Language Tour

Comments

// this is a single line comment# this is another single line comment/* This is a    block comment.*/

Data Types

s1="hello, 黄"       # strings are UTF-8 encodeds2= `hello,"world"`  # raw stringi=10                 # intu=10u                # uintf=10.0               # floatb=true               # boola=[1,"2"]           # arrayh={"a":1,"b":2}   # hasht=(1,2,3)            # tuplen=nil

Constants(Literal)

// Integer literalsi1=10i2=20_000_000     //for more readablei3=0x80           // hexi4=0b10101        // binaryi5=0o127          // octal// Unsigned Integer literalsui1=10uui2=20_000_000u     //for more readableui3=0x80u           // hexui4=0b10101u        // binaryui5=0o127u          // octal// Float literalsf1=10.25f2=1.02E3f3=123_456.789_012 //for more readable// String literalss1="123"s2="Hello world"// Regular expression literalsr=/\d+/.match("12")if(r){prinln("regex matched!")}// Array literalsa=[1+2,3,4,"5",3]// Hash literalsh={"a":1,"b":2,"c":2}//Tuple literalst=(1,2+3,"Hello",5)// Nil literaln=nil// Boolean literalst=truef=false// Function literalsletf1=add(x, y){return x+ y}println(f1(1,2))//fat-arrow function literalsletf2=(x, y)=> x+ yprintln(f2(1,2))

Variables

leta,b,c=1,"hello world",[1,2,3]d=4e=5姓="黄"

//righ-hand side is an arraylet(d,e,f)=[1,5,8]//d=1, e=5, f=8//right-hand side is a tuplelet(g, h, i)=(10,20,"hhf")//g=10, h=20, i=hhf//righ-hand side is a hashlet(j, k, l)={"j":50,"l":"good"}//j=50, k=nil, l=good

//Error, multiple variable assignments must be use `let` keyworda, b, c=1,"hello world",[1,2,3]

letx,y=10,20;letx,y= y,x //Swap the value of x and yprintf("x=%v, y=%v\n", x, y)  //result: x=20, y=10

letx, _,y=10,20,30printf("x=%d, y=%d\n", x, y) //result: x=10, y=30

Reserved keywords

Type conversion

leti=0xaletu=uint(i)                 // result: 10lets=str(i)                  // result: "10"letf=float(i)                // result: 10leta=array(i)                // result: [10]lett=tuple(i)                // result:(10,)leth=hash(("key","value"))  // result: {"key": "value}letd=decimal("123.45634567") // result: 123.45634567

lett=tuple([10,20])   //result:(10,20)

letarr=array((10,20))  //result:[10,20]

//create an empty hashleth1=hash()  //same as h1 = {}//create a hash from an arrayleth1=hash([10,20])     //result: {10 : 20}leth2=hash([10,20,30])   //result: {10 : 20, 30 : nil}//create a hash from a tupleleth3=hash((10,20))     //result: {10 : 20}leth4=hash((10,20,30))   //result: {10 : 20, 30 : nil}

qw(Quote word) keyword

for str inqw<abc,def,ghi,jkl,mno>{ //allowed 'qw' pair is '{}', '<>', '()'println('str={str}')}newArr=qw(1,2,3.5) //array with string values, not number values.fmt.printf("newArr=%v\n", newArr)

enum keyword

LogOption=enum{    Ldate=1 <<0,    Ltime=1 <<1,    Lmicroseconds=1 <<2,    Llongfile=1 <<3,    Lshortfile=1 <<4,    LUTC=1 <<5,    LstdFlags=1 <<4 |1 <<5}opt=LogOption.LstdFlagsprintln(opt)//get all names of the `enum`forsinLogOption.getNames(){ //not orderedprintln(s)}//get all values of the `enum`forsinLogOption.getValues(){ //not orderedprintln(s)}// get a specific name of the `enum`println(LogOption.getName(LogOption.Lshortfile))

Meta-Operators

letarr1=[1,2,3]~*[4,5,6]letarr2=[1,2,3]~*4letarr3=[1,2,"HELLO"]~*2letvalue1=~*[10,2,2]letvalue2=~+[2,"HELLO",2]println(arr1)   //result: [4, 10, 18]println(arr2)   //result: [4, 8, 12]println(arr3)   //result: [2,4,"HELLOHELLO"]println(value1) //result: 40println(value2) //result: 2HELLO2

Control flow

// if-elseleta,b=10,5if(a> b){println("a > b")}elseif a== b{ // could also use 'elsif', 'elseif' or 'elif'println("a = b")}else{println("a < b")}//unless-elseunless b> a{println("a >= b")} else{println("b > a")}// fori=9for{ // forever loop    i= i+2if(i>20){break}println('i={i}')}i=0for(i=0; i<5; i++){  // c-like for, '()' is a mustif(i>4){break}if(i==2){continue}    println('i is{i}')}i=0for(; i<5; i++){  // no initialization statement.if(i>4){break}if(i==2){continue}    println('i is{i}')}i=0for(; i<5;;){  // no updater statement.if(i>4){break}if(i==2){continue}    println('i is{i}')    i++ // Updater statement}i=0for(;;;){  // same as 'for { block }'if(i>4){break}    println('i is{i}')    i++ //update the 'i'}for i in range(10){println('i={i}')}a=[1,2,3,4]for i in awhere i%2!=0{println(i)}hs={"a":1,"b":2,"c":3,"d":4,"e":5,"f":6,"g":7}for k, v in hswhere v%2==0{println('{k}:{v}')}for i in1..5{println('i={i}')}for item in10..20where $_%2==0{ // $_ is the indexprintf("idx=%d, item=%d\n", $_, item)}for c in"m".."a"{println('c={c}')}for idx, v in"abcd"{printf("idx=%d, v=%s\n", idx, v)}for idx,v in["a","b","c","d"]{printf("idx=%d, v=%s\n", idx, v)}for item in["a","b","c","d"]where $_%2==0{ // $_ is the indexprintf("idx=%d, item=%s\n", $_, v)}//for loop is an expression, not statement, so it could be assigned to a variablelet plus_one=for i in[1,2,3,4]{ i+1}fmt.println(plus_one)// whilei=10while(i>3){    i--println('i={i}')}// doi=10do{    i--if(i==3){break}}// try-catch-finally(only support string type)let exceptStr="SUMERROR"try{letth=1+2if(th==3){throw exceptStr}}catch"OTHERERROR"{println("Catched OTHERERROR")}catch exceptStr{println("Catched is SUMERROR")}catch{println("Catched ALL")}finally{println("finally running")}// case-in/case-islet testStr="123"case testStr in{ // in(exact/partial match), is(only exact match)"abc","mno"{println("testStr is 'abc' or 'mno'")}"def"{println("testStr is 'def'")}    `\d+`{println("testStr contains digit")}    else{println("testStr not matched")}}let i=[{"a":1,"b":2},10]let x=[{"a":1,"b":2},10]case i in{1,2{println("i matched 1, 2")}3{println("i matched 3")}    x{println("i matched x")}    else{println("i not matched anything")}}

using statement

// Here we use 'using' statement, so we do not need to call infile.close().// When finished running 'using' statement, it will automatically call infile.close().using(infile=newFile("./file.demo","r")){if(infile==nil){println("opening 'file.demo' for reading failed, error:", infile.message())        os.exit(1)}letline;letnum=0    //Read file by using extraction operator(">>")while(infile>>line!=nil){        num++printf("%d%s\n", num, line)}}

User Defined Operator

//infix operator '=@' which accept two parameters.fn=@(x, y){return x+ y* y}//prefix operator '=^' which accept only one parameter.fn=^(x){return-x}letpp=10=@5 // Use the '=@' user defined infix operatorprintf("pp=%d\n", pp) // result: pp=35lethh==^10 // Use the '=^' prefix operatorprintf("hh=%d\n", hh) // result: hh=-10

fn.^(x, y){    arr=[]while x<= y{        arr+= x        x+=2}return arr}letpp=10.^20printf("pp=%v\n", pp) // result: pp=[10, 12, 14, 16, 18, 20]

Integer

x=(-1).next()println(x) //0x=-1.next() //equals 'x = -(1.next())println(x) //-2x=(-1).prev()println(x) //-2x=-1.prev() //equals 'x = -(1.prev())println(x) //0x=[i for i in10.upto(15)]println(x) //[10, 11, 12, 13, 14, 15]foriin10.downto(5){print(i,"") //10 9 8 7 6 5}println()if10.isEven(){println("10 is even")}if9.isOdd(){println("9 is odd")}

Float

f0=15.20println(f0)f1=15.20.ceil()println(f1)f2=15.20.floor()println(f2)

Decimal

d1= decimal.fromString("123.45678901234567")  //create decimal from stringd2= decimal.fromFloat(3)  //create decimal from float//set decimal division precision.//Note: this will affect all other code that followsdecimal.setDivisionPrecision(50)fmt.println("123.45678901234567/3 =", d1.div(d2))  //print d1/d2fmt.println(d1.div(d2)) //same as abovefmt.println(decimal.fromString("123.456").trunc(2)) //truncate decimal//convert string to decimald3=decimal("123.45678901234567")fmt.println(d3)fmt.println("123.45678901234567/3 =", d3.div(d2))

Array

emptyArr=[]emptyArr[3]=3 //will auto expand the arrayprintln(emptyArr)

//create an array with 10 elements initialized to nil.//Note: this only support integer literal.letarr=[]10println(arr)//use the builtin 'newArray' method.letanotherArr=newArray(len(arr))println(anotherArr) //result: [nil, nil, nil, nil, nil, nil, nil, nil, nil, nil]letarr1=["1","a5","5","5b","4","cc","7","dd","9"]letarr2=newArray(6, arr1,10,11,12) //first parameter is the sizeprintln(arr2) //result: ["1", "a5", "5", "5b", "4", "cc", "7", "dd", "9", 10, 11, 12]letarr3=newArray(20, arr1,10,11,12)println(arr3) //result : ["1", "a5", "5", "5b", "4", "cc", "7", "dd", "9", 10, 11, 12, nil, nil, nil, nil, nil, nil, nil, nil]

mixedArr=[1,2.5,"Hello",["Another","Array"],{"Name":"HHF","SEX":"Male"}]

println('mixedArr[2]={mixedArr[2]}')println(["a","b","c","d"][2])

if([].empty()){println("array is empty")}emptyArr.push("Hello")println(emptyArr)//you could also use 'addition' to add an item to an arrayemptyArr+=2println(emptyArr)//You could also use `<<(insertion operator)` to add item(s) to an array, the insertion operator support chain operation.emptyArr <<2 <<3println(emptyArr)

numArr=[1,3,5,2,4,6,7,8,9]foritemin numArrwhere item%2==0{println(item)}letstrArr=["1","a5","5","5b","4","cc","7","dd","9"]foritemin strArrwhere/^\d+/.match(item){println(item)}foritemin["a","b","c","d"]where $_%2==0{  //$_ is the indexprintf("idx=%d, v=%s\n", $_, item)}

letarr=[1,3,5,2,4,6,7,8,9]println("Source Array =", arr)revArr=reverse(arr)println("Reverse Array =", revArr)

letarr=[3,4]*3println(arr) // result: [3,4,3,4,3,4]

String

normalStr="Hello"+"world!"println(normalStr)println("123456"[2])rawStr= `Welcome tovisit us!`println(rawStr)//when you use single quoted string, and want variable to be interpolated,//you just put the variable into '{}'. see below:str="Hello world"println('str={str}') //output: "Hello world"str[6]="W"println('str={str}') //output: "Hello World"

三=3五=5println(三+ 五) //output : 8

upperStr="hello world".upper()println(upperStr) //output : HELLO WORLD

foridx, vin"abcd"{printf("idx=%d, v=%s\n", idx, v)}forvin"Hello World"{printf("idx=%d, v=%s\n", $_, v) //$_ is the index}

joinedStr="Hello"+"World"joinedStr+="!"println(joinedStr)

letstr="Hello world!"println("Source Str =", str)revStr=reverse(str)println("Reverse str =", revStr)

a=+"121314" // a is an intprintln(a) // result: 121314// Integer also support "0x"(hex), "0b"(binary), "0o"(octal) prefixa=+"0x10" // a is an intprintln(a) // result: 16a=+"121314.6789" // a is a floatprintln(a) // result: 121314.6789

Hash

emptyHash={}emptyHash["key1"]="value1"println(emptyHash)

hashObj={12:"twelve",true:1,"Name":"HHF"}println(hashObj)

hashObj+={"key1":"value1"}hashObj+={"key2":"value2"}hashObj+={5:"five"}hashObj-="key2"hashObj-=5println(hash)

hashObj.push(15,"fifteen") //first parameter is the key, second is the valuehashObj.pop(15)keys= hashObj.keys()println(keys)values= hashObj.values()println(values)

leths={"key1":12,"key2":"HHF","key3":false}println("Source Hash =", hs)revHash=reverse(hs)println("Reverse Hash =", revHash)

Tuple

//Create an empty tuplelett1=tuple()//Same as above.lett2=()// Create a one element tuple.// Note: the trailing comma is necessary to distinguish it from the//       parenthesized expression (1).// 1-tuples are seldom used.lett3=(1,)//Create a two elements tuplelett4=(2,3)

lett=tuple("hello")println(t)  // result: ("hello")

lett=(1,2,3)[2]print(t) // result:3

//for-loopforiin(1,2,3){println(i)}//tuple comprehensionlett1=[x+1 for x in(2,4,6)]println(t1) //result: [3, 5, 7]. Note: Result is array, not tuple

arr1=[1,2,3]t=(0, arr1,5,6)println(t)    // result: (0, [1, 2, 3], 5, 6)arr1.push(4)println(t)    //result:  (0, [1, 2, 3, 4], 5, 6)

key1=(1,2,3)key2=(2,3,4)letht={key1:10, key2:20}println(ht[key1]) // result: 10println(ht[key2]) // result: 20//Below is not supported(will issue a syntax error):letht={(1,2,3):10,(2,3,4):20} //error!println(ht[(1,2,3)])  //error!println(ht[(2,3,4)])  //error!

lett=(1,2)+(3,4)println(t) // result: (1, 2, 3, 4)

lett=(1,)if t{println("t is not empty!")}else{println("t is empty!")}//result : "t is not empty!"

lettupleJson=("key1","key2")lettupleStr= json.marshal(tupleJson)//Result:[//        "key1"，//        "key2"，//       ]println(json.indent(tupleStr,""))lettupleJson1= json.unmarshal(tupleStr)println(tupleJson1) //result: ["key1", "key2"]

t2=(1,2,3)+[4,5,6]println(t2) // result: [(1, 2, 3), 4, 5, 6]

lettp=(1,3,5,2,4,6,7,8,9)println(tp) //result: (1, 3, 5, 2, 4, 6, 7, 8, 9)revTuple=reverse(tp)println(revTuple) //result: (9, 8, 7, 6, 4, 2, 5, 3, 1)

class

class Animal{letname=""    fn init(name){    //'init' is the constructor        //do somthing}}

classAnimal:object{letname=""    fn init(name){    //'init' is the constructor        //do somthing}}

inheritance and polymorphism

classDog:Animal{ //Dog inherits from Animal}

class Animal{letName;    fn MakeNoise(){        println("generic noise")}fn ToString(){return"oooooooo"}}class Cat:Animal{    fn init(name){        this.Name= name}    fn MakeNoise(){println("Meow")}fn ToString(){return Name+" cat"}}class Dog:Animal{    fn init(name){        this.Name= name}    fn MakeNoise(){println("Woof!")}fn ToString(){return Name+" dog"}fn OnlyDogMethod(){println("secret dog only method")}}cat=new Cat("pearl")dog=new Dog("cole")randomAnimal=new Animal()animals=[cat, dog, randomAnimal]foranimalin animals{println("Animal name:"+ animal.Name)    animal.MakeNoise()println(animal.ToString())ifis_a(animal,"Dog"){        animal.OnlyDogMethod()}}

Animal name: pearlMeowpearl catAnimal name: coleWoof!cole dogsecret dog only methodAnimal name: nilgeneric noiseoooooooo

operator overloading

class Vector{letx=0;lety=0;    // constructor    fn init(a, b, c){if(!a){ a=0;}if(!b){b=0;}        x= a; y= b}    fn+(v){ //overloading '+'        if(type(v)=="INTEGER"{returnnew Vector(x+ v, y+ v);} elseif v.is_a(Vector){returnnew Vector(x+ v.x, y+ v.y);}        return nil;}    fn String(){return fmt.sprintf("(%v),(%v)", this.x, this.y);}}fn Vectormain(){    v1=new Vector(1,2);    v2=new Vector(4,5);        // call + function in the vector object    v3= v1+ v2 //same as 'v3 = v1.+(v2)'    // returns string "(5),(7)"println(v3.String());        v4= v1+10 //same as v4 = v1.+(10);    //returns string "(11),(12)"println(v4.String());}Vectormain()

property(like c#)

classDate{letmonth=7;  // Backing store    property Month{        get{return month}set{if((value>0) &&(value<13)){                month= value}else{println("BAD, month is invalid")}}}    property Year; // same as 'property Year { get; set;}'property Day{ get;}property OtherInfo1{ get;}property OtherInfo2{ set;}fn init(year, month, day){        this.Year= year        this.Month= month        this.Day= day}fn getDateInfo(){printf("Year:%v, Month:%v, Day:%v\n", this.Year, this.Month, this.Day) //note here, you need to use 'this.Property', not 'Property'}}dateObj=new Date(2000,5,11)//printf("Calling Date's getter, month=%d\n", dateObj.Month)dateObj.getDateInfo()println()dateObj.Month=10printf("dateObj.Month=%d\n", dateObj.Month)dateObj.Year=2018println()dateObj.getDateInfo()//Below code will raise an execution error! Because OtherInfo1 is a READONLY property.//dateObj.OtherInfo1 = "Other Date Info"//println(dateObj.OtherInfo1)//Below code will raise an execution error! Because OtherInfo2 is a WRITEONLY property.//dateObj.OtherInfo2 = "Other Date Info2"//println(dateObj.OtherInfo2)//Below code will raise an execution error! Because Day is a READONLY property.//dateObj.Day = 18

indexer

property this[index]{get{ xxx}set{ xxx}}

classIndexedNames{letnamelist=[]letsize=10    fn init(){leti=0        for(i=0; i< size; i++){            namelist[i]="N. A."}}    fn getNameList(){println(namelist)}    property this[index]{get{lettmp;if( index>=0 && index<= size-1){               tmp=namelist[index]}else{               tmp=""}return tmp}set{if( index>=0 && index<= size-1){namelist[index]= value}}}}fn Main(){    namesObj=new IndexedNames()    //Below code will call Indexer's setter functionnamesObj[0]="Zara"namesObj[1]="Riz"namesObj[2]="Nuha"namesObj[3]="Asif"namesObj[4]="Davinder"namesObj[5]="Sunil"namesObj[6]="Rubic"    namesObj.getNameList()    for(i=0; i< namesObj.size; i++){println(namesObj[i]) //Calling Indexer's getter function}}Main()

static members/methods/properties

class Test{staticletx=0;staticlety=5;static fn Main(){      println(Test.x);println(Test.y);Test.x=99;println(Test.x);}}Test.Main()

Class Category

class Animal{    fn Walk(){        println("Animal Walk!")}}//Class category like objective-cclass Animal(Run){ //Create an 'Run' category of Animal class.fn Run(){println("Animal Run!")        this.Walk() //can call Walk() method of Animal class.}}animal=new Animal()animal.Walk()println()animal.Run()

Annotations

//Declare annotation class//Note: In the body, you must use property, not method.class@MinMaxValidator{  property MinLength  property MaxLength default10 //Same as 'property MaxLength = 10'}//This is a marker annotationclass@NoSpaceValidator{}class@DepartmentValidator{  property Department}//The 'Request' classclass Request{@MinMaxValidator(MinLength=1)  property FirstName; // getter and setter is implicit@NoSpaceValidator  property LastName;@DepartmentValidator(Department=["Department of Education","Department of Labors","Department of Justice"])  property Dept;}//This class is responsible for processing the annotation.class RequestHandler{static fn handle(o){    props= o.getProperties()forpin props{      annos= p.getAnnotations()forannoin annos{if anno.instanceOf(MinMaxValidator){          //p.value is the property real value.iflen(p.value)> anno.MaxLength ||len(p.value)< anno.MinLength{printf("Property '%s' is not valid!\n", p.name)}} elseif anno.instanceOf(NoSpaceValidator){forcin p.value{if c=="" || c=="\t"{printf("Property '%s' is not valid!\n", p.name)break}}} elseif anno.instanceOf(DepartmentValidator){          found=falsefordin anno.Department{if p.value== d{              found=true}}if !found{printf("Property '%s' is not valid!\n", p.name)}}}}}}class RequestMain{static fn main(){    request=new Request()    request.FirstName="Haifeng123456789"    request.LastName="Huang"    request.Dept="Department of Justice"RequestHandler.handle(request)}}RequestMain.main()

Property 'FirstName' is not valid!Property 'LastName' is not valid!

Standard input/output/error

stdout.writeLine("Hello world")//same as abovefmt.fprintf(stdout,"Hello world\n")print("Please type your name:")name= stdin.read(1024)  //read up to 1024 bytes from stdinprintln("Your name is"+ name)

// Output to stdout by using insertion operator("<<")// 'endl' is a predefined object, which is "\n".stdout <<"hello" <<"world!" <<" How are you?" << endl;// Read from stdin by using extraction operator(">>")letname;stdout <<"Your name please:";stdin >> name;printf("Welcome, name=%v\n", name)

//Read file by using extraction operator(">>")infile=newFile("./file.demo","r")if(infile==nil){println("opening 'file.demo' for reading failed, error:", infile.message())    os.exit(1)}letline;letnum=0while( infile>>line!=nil){    num++printf("%d%s\n", num, line)}infile.close()//Writing to file by using inserttion operator("<<")outfile=newFile("./outfile.demo","w")if(outfile==nil){println("opening 'outfile.demo' for writing failed, error:", outfile.message())    os.exit(1)}outfile <<"Hello" << endloutfile <<"world" << endloutfile.close()

Error Handling of standard library

file=newFile(filename,"r")if(file==nil){println("opening", filename,"for reading failed, error:", file.message())}//do something with the file//close the filefile.close()letret= http.listenAndServe("127.0.0.1:9090")if(ret==false){println("listenAndServe failed, error:", ret.message())}

Aboutdefer keyword

letadd=fn(x,y){defer println("I'm defer1")println("I'm in add")defer println("I'm defer2")return x+ y}println(add(2,2))

I'm in addI'm defer2I'm defer14

file=newFile(filename,"r")if(file==nil){println("opening", filename,"for reading failed, error:", file.message())returnfalse}defer file.close()//do other file related stuff, and not need to worry about the file close.//when any file operation error occurs, it will close the file before it returns.

Concatenation of different types

// Number plus assignmentnum=10num+=10+15.6num+=20println(num)// String plus assignmentstr="Hello"str+="world!"str+=[1,2,3]println(str)// Array plus assignmentarr=[]arr+=1arr+=10.5arr+=[1,2,3]arr+={"key":"value"}println(arr)// Array comparearr1=[1,10.5,[1,2,3],{"key":"value"}]println(arr1)if arr== arr1{ //support ARRAY compareprintln("arr1 = arr")}else{println("arr1 != arr")}// Hash assignment("+=", "-=")hash={}hash+={"key1":"value1"}hash+={"key2":"value2"}hash+={5:"five"}println(hash)hash-="key2"hash-=5println(hash)

Comprehensions

//array comprehensionx=[[word.upper(), word.lower(), word.title()] for word in["hello","world","good","morning"]]println(x) //result: [["HELLO", "hello", "Hello"], ["WORLD", "world", "World"], ["GOOD", "good", "Good"], ["MORNING", "morning", "Morning"]]//string comprehension (here string is treated like an array)y=[ c.upper() for c in"huanghaifeng"where $_%2!=0] //$_ is the indexprintln(y) //result: ["U", "N", "H", "I", "E", "G"]//range comprehensionw=[i+1 for i in2..10]println(w) //result: [2, 3, 4, 5, 6, 7, 8, 9, 10, 11]//tuple comprehensionv=[x+1 for x in(12,34,56)]println(v) //result: [13, 35, 57]//hash comprehensionz=[v*10 for k,v in{"key1":10,"key2":20,"key3":30}]println(z) //result: [100, 200, 300]

//hash comprehension (from hash)z1={v:k for k,v in{"key1":10,"key2":20,"key3":30}} //reverse key-value pairprintln(z1) // result: {10 : "key1", 20 : "key2", 30 : "key3"}. Order may differ//hash comprehension (from array)z2={x:x**2 for x in[1,2,3]}println(z2) // result: {1 : 1, 2 : 4, 3 : 9}. Order may differ//hash comprehension (from .. range)z3={x:x**2 for x in5..7}println(z3) // result: {5 : 25, 6 : 36, 7 : 49}. Order may differ//hash comprehension (from string)z4={x:x.upper() for x in"hi"}println(z4) // result: {"h" : "H", "i" : "I"}. Order may differ//hash comprehension (from tuple)z5={x+1:x+2 for x in(1,2,3)}println(z5) // result: {4 : 5, 2 : 3, 3 : 4}. Order may differ

grep and map

letsourceArr=[2,4,6,8,10,12]letm= grep  $_>5,sourceArrprintln('m is{m}')letcp= map $_*2,sourceArrprintln('cp is{cp}')//a little bit more complex exampleletfields={"animal":"dog","building":"house","colour":"red","fruit":"apple"}letpattern= `animal|fruit`// =~(match), !~(unmatch)letvalues=map{fields[$_]} grep{ $_=~ pattern} fields.keys()println(values)

Function

//define a functionletadd=fn(){[5,6]}letn=[1,2]+[3,4]+ add()println(n)letcomplex={"add": fn(x, y){returnfn(z){x+ y+ z}}, //function with closure"sub": fn(x, y){ x- y},"other":[1,2,3,4]}println(complex["add"](1,2)(3))println(complex["sub"](10,2))println(complex["other"][2])letwarr=[1+1,3,fn(x){ x+1}(2),"abc","def"]println(warr)println("\nfor i in 5..1 where i > 2 :")foriinfn(x){ x+1}(4)..fn(x){ x+1}(0)where i>2{if(i==3){continue}println('i={i}')}// default parameter and variadic parametersadd=fn(x, y=5, z=7, args...){    w= x+ y+ zforiin args{        w+= i}return w}w=add(2,3,4,5,6,7)println(w)

fn sub(x,y=2){return x- y}println(sub(10)) //output : 8

letx=()=>5+5println(x())  //result: 10lety=(x)=> x*5println(y(2)) //result: 10letz=(x,y)=> x* y+5println(z(3,4)) //result :17letadd=fn(x, factor){  x+ factor(x)}result=add(5,(x)=> x*2)println(result)  //result : 15

println("hhf".upper)  //result: "HHF"//Same as aboveprintln("hhf".upper())

fn div(x, y){if y==0{return[nil,"y could not be zero"]}return[x/y,""]}ret=div(10,5)ifret[1]!=""{println(ret[1])}else{println(ret[0])}

fn testReturn(a, b, c, d=40){return a, b, c, d}let(x, y, c, d)=testReturn(10,20,30)// let x, y, c, d = testReturn(10, 20, 30)  same as aboveprintf("x=%v, y=%v, c=%v, d=%v\n", x, y, c, d)//Result: x=10, y=20, c=30, d=40

(x, y, c, d)=testReturn(10,20,30) // no 'let', compile errorx, y, c, d=testReturn(10,20,30)   // no 'let', compile error

Pipe Operator

# Test pipe operator(|>)x=["hello","world"]|> strings.join("")|> strings.upper()|> strings.lower()|> strings.title()printf("x=<%s>\n", x)letadd=fn(x,y){return x+ y}letpow=fn(x){return x**2}letsubtract=fn(x){return x-1}letmm=add(1,2)|>pow()|>subtract()printf("mm=%d\n", mm)"Hello %s!\n"|> fmt.printf("world")

Spawn and channel

letaChan=chan()spawn fn(){letmessage= aChan.recv()println('channel received message=<{message}>')}()//send message to threadaChan.send("Hello Channel!")

// XRange is an iterator over all the numbers from 0 to the limit.fn XRange(limit){    ch=chan()spawn fn(){        //for (i = 0; i <= limit; i++)  // Warning: Never use this kind of for loop, or else you will get weird results.foriin0..limit{            ch.send(i)}        // Ensure that at the end of the loop we close the channel!        ch.close()}()return ch}foriinXRange(10){    fmt.println(i)}

Usego language modules

// Because in monkey we already have built in module `fmt`, here we use `gfmt` for package name.eval.RegisterFunctions("gfmt",[]interface{}{    fmt.Errorf,    fmt.Println, fmt.Print, fmt.Printf,    fmt.Fprint, fmt.Fprint, fmt.Fprintln, fmt.Fscan, fmt.Fscanf, fmt.Fscanln,    fmt.Scan, fmt.Scanf, fmt.Scanln,    fmt.Sscan, fmt.Sscanf, fmt.Sscanln,    fmt.Sprint, fmt.Sprintf, fmt.Sprintln,})eval.RegisterFunctions("io/ioutil",[]interface{}{    ioutil.WriteFile, ioutil.ReadFile, ioutil.TempDir, ioutil.TempFile,    ioutil.ReadAll, ioutil.ReadDir, ioutil.NopCloser,})eval.Eval(program, scope)

gfmt.Printf("Hello %s!\n","go function");//Note Here: we use 'io_ioutil', not 'io/ioutil'.letfiles,err= io_ioutil.ReadDir(".")if err!=nil{    gfmt.Println(err)}forfilein files{if file.Name()==".git"{continue}    gfmt.Printf("Name=%s, Size=%d\n", file.Name(), file.Size())}

Standard module introduction

fmt module

leti,f,b,s,aArr,aHash=108,25.383,true,"Hello, world",[1,2,3,4,"a","b"],{"key1":1,"key2":2,"key3":"abc"}// Use '%v (value)' to print variable value, '%_' to print the variable's typefmt.printf("i=[%05d, %X], b=[%t], f=[%.5f], s=[%-15s], aArr=%v, aHash=%v\n", i, i, b, f, s, aArr, aHash)fmt.printf("i=[%_], b=[%t], f=[%f], aArr=%_, aHash=%_, s=[%s]\n", i, b, f, aArr, aHash, s)sp= fmt.sprintf("i=[%05d, %X], b=[%t], f=[%.5f], s=[%-15s]\n", i, i, b, f, s)fmt.printf("sp=%s", sp)fmt.fprintf(stdout,"Hello %s\n","world")

time module

t1=newTime()format= t1.strftime("%F %R")println(t1.toStr(format))Epoch= t1.toEpoch()println(Epoch)t2= t1.fromEpoch(Epoch)println(t2.toStr(format))

logger module

#Log to stdoutlog=newLogger(stdout,"LOGGER-", logger.LSTDFLAGS | logger.LMICROSECONDS)log.printf("Hello, %s\n","logger")fmt.printf("Logger: flags =<%d>, prefix=<%s>\n", log.flags(), log.prefix())#Log to filefile=newFile("./logger.log","a+")log.setOutput(file)foriin1..5{    log.printf("This is <%d>\n", i)}file.close() //do not forget to close the file

flag module(for handling of command line options)

letverV= flag.bool("version",false,"0.1")letageV= flag.int("age",40,"an int")letheightV= flag.float("height",120.5,"a float")letnameV= flag.string("name","HuangHaiFeng","a string")lethobbiesV= flag.string("hobbies","1,2,3","a comma-delimited string")flag.parse()println("verV =", verV)println("ageV =", ageV)println("heightV =", heightV)println("nameV =", nameV)println("hobbies =", hobbiesV.split(","))if(flag.isSet("age")){println("age is set")}else{println("age is not set")}

json module(for json marshal & unmarshal)

lethsJson={"key1":10,"key2":"Hello Json %s %s Module","key3":15.8912,"key4":[1,2,3.5,"Hello"],"key5": true,"key6":{"subkey1":12,"subkey2":"Json"},"key7": fn(x,y){x+y}(1,2)}lethashStr= json.marshal(hsJson) //same as `json.toJson(hsJson)`println(json.indent(hashStr,""))lethsJson1= json.unmarshal(hashStr)println(hsJson1)letarrJson=[1,2.3,"HHF",[],{"key":10,"key1":11}]letarrStr= json.marshal(arrJson)println(json.indent(arrStr))letarr1Json= json.unmarshal(arrStr)  //same as `json.fromJson(arrStr)`println(arr1Json)

net module

//A simple tcp clientletconn=dialTCP("tcp","127.0.0.1:9090")if(conn==nil){println("dailTCP failed, error:", conn.message())    os.exit(1)}letn= conn.write("Hello server, I'm client")if(n==nil){println("conn write failed, error:", n.message())    os.exit(1)}letret= conn.close()if(ret==false){println("Server close failed, error:", ret.message())}//A simple tcp serverletln=listenTCP("tcp",":9090")for{letconn= ln.acceptTCP()if(conn==nil){println(conn.message())}else{printf("Accepted client, Address=%s\n", conn.addr())}spawn fn(conn){ //spawn a thread to handle the connectionprintln(conn.read())}(conn)} //end forletret= ln.close()if(ret==false){println("Server close failed, error:", ret.message())}

linq module

letmm=[1,2,3,4,5,6,7,8,9,10]println('before mm={mm}')result= linq.from(mm).where(fn(x){    x%2==0}).select(fn(x){    x= x+2}).toSlice()println('after result={result}')result= linq.from(mm).where(fn(x){    x%2==0}).select(fn(x){    x= x+2}).last()println('after result={result}')letsortArr=[1,2,3,4,5,6,7,8,9,10]result= linq.from(sortArr).sort(fn(x,y){return x> y})println('[1,2,3,4,5,6,7,8,9,10] sort(x>y)={result}')result= linq.from(sortArr).sort(fn(x,y){return x< y})println('[1,2,3,4,5,6,7,8,9,10] sort(x<y)={result}')thenByDescendingArr=[{"Owner":"Google","Name":"Chrome"},{"Owner":"Microsoft","Name":"Windows"},{"Owner":"Google","Name":"GMail"},{"Owner":"Microsoft","Name":"VisualStudio"},{"Owner":"Google","Name":"GMail"},{"Owner":"Microsoft","Name":"XBox"},{"Owner":"Google","Name":"GMail"},{"Owner":"Google","Name":"AppEngine"},{"Owner":"Intel","Name":"ParallelStudio"},{"Owner":"Intel","Name":"VTune"},{"Owner":"Microsoft","Name":"Office"},{"Owner":"Intel","Name":"Edison"},{"Owner":"Google","Name":"GMail"},{"Owner":"Microsoft","Name":"PowerShell"},{"Owner":"Google","Name":"GMail"},{"Owner":"Google","Name":"GDrive"}]result= linq.from(thenByDescendingArr).orderBy(fn(x){returnx["Owner"]}).thenByDescending(fn(x){returnx["Name"]}).toOrderedSlice()    //Note: You need to use toOrderedSlice//use json.indent() for formatting the outputletthenByDescendingArrStr= json.marshal(result)println(json.indent(thenByDescendingArrStr,""))//test 'selectManyByIndexed'println()letselectManyByIndexedArr1=[[1,2,3],[4,5,6,7]]result= linq.from(selectManyByIndexedArr1).selectManyByIndexed(fn(idx, x){if idx==0{return linq.from([10,20,30])}return linq.from(x)},fn(x,y){return x+1})println('[[1,2,3],[4,5,6,7]] selectManyByIndexed()={result}')letselectManyByIndexedArr2=["st","ng"]result= linq.from(selectManyByIndexedArr2).selectManyByIndexed(fn(idx,x){if idx==0{return linq.from(x+"r")}return linq.from("i"+ x)},fn(x,y){return x+"_"})println('["st","ng"] selectManyByIndexed()={result}')