Not so Terse Guide to Pharo
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| "************************************************************************** | |
| * Allowable characters: * | |
| * - a-z * | |
| * - A-Z * | |
| * - 0-9 * | |
| * - .+/\*~<>@%|&? * | |
| * - blank, tab, cr, ff, lf * | |
| * * | |
| * Variables: * | |
| * - variables must be declared before use * | |
| * - shared vars must begin with uppercase * | |
| * - local vars must begin with lowercase * | |
| * - reserved names: nil, true, false, self, super, and thisContext * | |
| * * | |
| * Variable scope: * | |
| * - Global: defined in Dictionary Smalltalk and accessible by all * | |
| * objects in system * | |
| * - Special: (reserved) thisContext, super, self, true, false, & nil * | |
| * - Method Temporary: local to a method * | |
| * - Block Temporary: local to a block * | |
| * - Pool: variables in a Dictionary object * | |
| * - Method Parameters: automatic local vars created as a result of * | |
| * message call with params * | |
| * - Block Parameters: automatic local vars created as a result of * | |
| * value: message call * | |
| * - Class: shared with all instances of one class & its subclasses * | |
| * - Class Instance: unique to each instance of a class * | |
| * - Instance Variables: unique to each instance * | |
| * * | |
| * Class and method definition: * | |
| * - Classes are defined inside packages * | |
| * - Methods are public and virtual * | |
| * - By default a method returns the receiver * | |
| * - Class methods are just methods of the class * | |
| **************************************************************************" | |
| "Comments are enclosed in quotes" | |
| "Period (.) is the statement seperator" | |
| "************************************************************************ | |
| * Transcript: * | |
| ************************************************************************" | |
| Transcript clear. "clear to transcript window" | |
| Transcript show: 'Hello World'. "output string in transcript window" | |
| Transcript nextPutAll: 'Hello World'. "output string in transcript window" | |
| Transcript nextPut: $A. "output character in transcript window" | |
| Transcript space. "output space character in transcript window" | |
| Transcript tab. "output tab character in transcript window" | |
| Transcript cr. "carriage return / linefeed" | |
| 'Hello' printOn: Transcript. "append print string into the window" | |
| 'Hello' storeOn: Transcript. "append store string into the window" | |
| Transcript endEntry. "flush the output buffer" | |
| "************************************************************************ | |
| * Assignment: * | |
| ************************************************************************" | |
| | x y | | |
| x := 5. "assignment" | |
| x := y := z := 6. "compound assignment" | |
| x := (y := 6) + 1. | |
| x := 'A1'. y := 'B2'. x become: y. "switch two objects" | |
| x := Object new. "bind to allocated instance of a class" | |
| x := 123 class. "discover the object class" | |
| x := Integer superclass. "discover the superclass of a class" | |
| x := Object allInstances. "get an array of all instances of a class" | |
| x := Integer allSuperclasses. "get all superclasses of a class" | |
| x := 1.2 hash. "hash value for object" | |
| y := x copy. "copy object" | |
| y := x shallowCopy. "copy object (not overridden)" | |
| y := x deepCopy. "copy object and instance vars" | |
| y := x veryDeepCopy. "complete tree copy using a dictionary" | |
| "************************************************************************ | |
| * Constants: * | |
| ************************************************************************" | |
| | b | | |
| b := true. "true constant" | |
| b := false. "false constant" | |
| x := nil. "nil object constant" | |
| x := 1. "integer constants" | |
| x := 8r177. "octal integer constant" | |
| x := 3.14. "float constants" | |
| x := 2r1010. "arbitrary base integer" | |
| x := 2r1.1. "arbitrary base float" | |
| x := 2r1.1e2. "float with exponent" | |
| x := 2e-2. "fractional constants" | |
| x := 16r0F. "hex constant". | |
| x := 36rPHARO5. "number in base 36" | |
| x := -1. "negative constants" | |
| x := 'Hello'. "string constant" | |
| x := 'I''m here'. "single quote escape" | |
| x := $A. "character constant" | |
| x := $ . "character constant (space)" | |
| x := #aSymbol. "symbol constants" | |
| x := #'It''s a symbol!'. "quoted symbol literal" | |
| x := #(3 2 1). "array constants" | |
| x := #[255 255 0]. "byte array constant" | |
| x := #(2 2.0 #two two 'two' #($t $w $o) #[2 2]). "nested array literal" | |
| x := #('abc' 2 $a). "mixing of types allowed" | |
| "************************************************************************ | |
| * Booleans: * | |
| ************************************************************************" | |
| | b x y | | |
| x := 1. y := 2. | |
| b := x = y. "equals" | |
| b := x ~= y. "not equals" | |
| b := x == y. "identical" | |
| b := x ~~ y. "not identical" | |
| b := x > y. "greater than" | |
| b := x < y. "less than" | |
| b := x >= y. "greater than or equal" | |
| b := x <= y. "less than or equal" | |
| b := b not. "boolean not" | |
| b := x < 5 & (y > 1). "boolean and" | |
| b := x < 5 | (y > 1). "boolean or" | |
| b := x < 5 and: [y > 1]. "boolean and (short-circuit)" | |
| b := x < 5 or: [y > 1]. "boolean or (short-circuit)" | |
| b := x < 5 eqv: (y > 1). "test if both true or both false" | |
| b := x < 5 xor: (y > 1). "test if one true and other false" | |
| b := 5 between: 3 and: 12. "between (inclusive)" | |
| b := 123 isKindOf: Number. "test if object is class or subclass of" | |
| b := 123 isMemberOf: SmallInteger. "test if object is type of class" | |
| b := 123 respondsTo: sqrt. "test if object responds to message" | |
| b := x isNil. "test if object is nil" | |
| b := x isZero. "test if number is zero" | |
| b := x positive. "test if number is positive" | |
| b := x strictlyPositive. "test if number is greater than zero" | |
| b := x negative. "test if number is negative" | |
| b := x even. "test if number is even" | |
| b := x odd. "test if number is odd" | |
| b := x isLiteral. "test if literal constant" | |
| b := x isInteger. "test if object is integer" | |
| b := x isFloat. "test if object is float" | |
| b := x isNumber. "test if object is number" | |
| b := $A isUppercase. "test if upper case character" | |
| b := $A isLowercase. "test if lower case character" | |
| "************************************************************************ | |
| * Arithmetic expressions: * | |
| ************************************************************************" | |
| | x | | |
| x := 6 + 3. "addition" | |
| x := 6 - 3. "subtraction" | |
| x := 6 * 3. "multiplication" | |
| x := 1 + 2 * 3. "evaluation always left to right (1 + 2) * 3" | |
| x := 5 / 3. "division with fractional result" | |
| x := 5.0 / 3.0. "division with float result" | |
| x := 5.0 // 3.0. "integer divide" | |
| x := 5.0 \\ 3.0. "integer remainder" | |
| x := -5. "unary minus" | |
| x := 5 sign. "numeric sign (1, -1 or 0)" | |
| x := 5 negated. "negate receiver" | |
| x := 1.2 integerPart. "integer part of number (1.0)" | |
| x := 1.2 fractionPart. "fractional part of number (0.2)" | |
| x := 5 reciprocal. "reciprocal function" | |
| x := 6 * 3.1. "auto convert to float" | |
| x := 5 squared. "square function" | |
| x := 25 sqrt. "square root" | |
| x := 5 raisedTo: 2. "power function" | |
| x := 5 raisedToInteger: 2. "power function with integer" | |
| x := 5 exp. "exponential" | |
| x := -5 abs. "absolute value" | |
| x := 3.99 rounded. "round" | |
| x := 3.99 truncated. "truncate" | |
| x := 3.99 roundTo: 1. "round to specified decimal places" | |
| x := 3.99 truncateTo: 1. "truncate to specified decimal places" | |
| x := 3.99 floor. "truncate" | |
| x := 3.99 ceiling. "round up" | |
| x := 5 factorial. "factorial" | |
| x := -5 quo: 3. "integer divide rounded toward zero" | |
| x := -5 rem: 3. "integer remainder rounded toward zero" | |
| x := 28 gcd: 12. "greatest common denominator" | |
| x := 28 lcm: 12. "least common multiple" | |
| x := 100 ln. "natural logarithm" | |
| x := 100 log. "base 10 logarithm" | |
| x := 100 log: 10. "logarithm with specified base" | |
| x := 100 floorLog: 10. "floor of the log" | |
| x := 180 degreesToRadians. "convert degrees to radians" | |
| x := 3.14 radiansToDegrees. "convert radians to degrees" | |
| x := 0.7 sin. "sine" | |
| x := 0.7 cos. "cosine" | |
| x := 0.7 tan. "tangent" | |
| x := 0.7 arcSin. "arcsine" | |
| x := 0.7 arcCos. "arccosine" | |
| x := 0.7 arcTan. "arctangent" | |
| x := 10 max: 20. "get maximum of two numbers" | |
| x := 10 min: 20. "get minimum of two numbers" | |
| x := Float pi. "pi" | |
| x := Float e. "exp constant" | |
| x := Float infinity. "infinity" | |
| x := Float nan. "not-a-number" | |
| x := Random new next; yourself. x next. "random number stream (0.0 to 1.0)" | |
| x := 100 atRandom. "quick random number" | |
| "************************************************************************ | |
| * Bitwise Manipulation: * | |
| ************************************************************************" | |
| | b x | | |
| x := 2r1111 bitAnd: 2r0100. "and bits" | |
| x := 4r3333 bitAnd: 2r011011011. "and with different bases" | |
| x := 2r1111 bitOr: 2r0100. "or bits" | |
| x := 16rFF bitXor: 8r5252. "xor bits mixing bases" | |
| x := 16rFF bitInvert. "invert bits" | |
| x := 2r0100 bitShift: 2. "left shift" | |
| x := 2r0100 bitShift: -2. "right shift" | |
| x := 2r0100 >> 2. "divide by four" | |
| x := 2r0100 << 2. "multiply by four" | |
| x := 2r0100 bitAt: 3. "bit at position (0|1)" | |
| x := 2r0100 highBit. "position of highest bit set" | |
| b := 16rFF allMask: 16r0F. "test if all bits set in mask set in receiver" | |
| b := 16rFF anyMask: 16r0F. "test if any bits set in mask set in receiver" | |
| b := 16rFF noMask: 16r0F. "test if all bits set in mask clear in receiver" | |
| "************************************************************************ | |
| * Conversion: * | |
| ************************************************************************" | |
| | x | | |
| x := 3.99 asInteger. "convert number to integer (truncates)" | |
| x := 3.99 asFraction. "convert number to fraction" | |
| x := 3 asFloat. "convert number to float" | |
| x := 65 asCharacter. "convert integer to character" | |
| x := $A asciiValue. "convert character to integer" | |
| x := 3.99 printString. "convert object to string via printOn:" | |
| x := 3.99 storeString. "convert object to string via storeOn:" | |
| x := 15 radix: 16. "convert to string in given base" | |
| x := 15 printStringBase: 2. "string in given base" | |
| "************************************************************************ | |
| * Blocks: * | |
| * - blocks are objects and may be assigned to a variable * | |
| * - value is last expression evaluated unless explicit return * | |
| * - blocks may be nested * | |
| * - specification [ arguments | | localvars | expressions ] * | |
| * - max of three arguments allowed * | |
| * - ^expression terminates block & method (exits all nested blocks) * | |
| * - blocks intended for long term storage should not contain ^ * | |
| ************************************************************************" | |
| | x y z | | |
| x := [ y := 1. z := 2. ]. x value. "simple block usage" | |
| x := [ :argOne :argTwo | argOne, ' and ' , argTwo.]. "set up block with argument passing" | |
| Transcript show: (x value: 'First' value: 'Second'); cr. "use block with argument passing" | |
| x := [ | t | t := 1.]. "local var in block" | |
| "************************************************************************ | |
| * Method calls (in order of priority): * | |
| * - unary methods are messages with no arguments * | |
| * - binary methods * | |
| * - keyword methods are messages with selectors including colons * | |
| * * | |
| * Method lookup: * | |
| * - follows the inheritance chain * | |
| * - self send triggers a dynamic lookup starting with receiver * | |
| * - super send triggers a static lookup starting with the * | |
| * receiver's superclass * | |
| * * | |
| * standard categories/protocols: * | |
| * - initializing (methods called for new instance) * | |
| * - accessing (get/set methods) * | |
| * - testing (boolean tests - is) * | |
| * - comparing (boolean tests with parameter * | |
| * - displaying (gui related methods) * | |
| * - printing (methods for printing) * | |
| * - updating (receive notification of changes) * | |
| * - private (methods private to class) * | |
| ************************************************************************" | |
| | x | | |
| x := 2 sqrt. "unary message" | |
| x := 2 raisedTo: 10. "keyword message" | |
| x := 194 * 9. "binary message" | |
| Transcript show: (194 * 9) printString; cr. "combination (chaining)" | |
| x := 2 perform: #sqrt. "indirect method invocation" | |
| Transcript "Cascading - send multiple messages to receiver" | |
| show: 'hello '; | |
| show: 'world'; | |
| cr. | |
| x := 3 + 2; * 100. "result=300. Sends message to same receiver (3)" | |
| "************************************************************************ | |
| * Conditional Statements: * | |
| ************************************************************************" | |
| | x switch result | | |
| X := 20 atRandom. | |
| x > 10 ifTrue: [Transcript show: 'ifTrue'; cr]. "if then" | |
| x > 10 ifFalse: [Transcript show: 'ifFalse'; cr]. "if else" | |
| x > 10 "if then else" | |
| ifTrue: [Transcript show: 'ifTrue'; cr] | |
| ifFalse: [Transcript show: 'ifFalse'; cr]. | |
| x > 10 "if else then" | |
| ifFalse: [Transcript show: 'ifFalse'; cr] | |
| ifTrue: [Transcript show: 'ifTrue'; cr]. | |
| Transcript | |
| show: | |
| (x > 10 | |
| ifTrue: ['ifTrue'] | |
| ifFalse: ['ifFalse']); | |
| cr. | |
| Transcript "nested if then else" | |
| show: | |
| (x > 10 | |
| ifTrue: [x > 5 | |
| ifTrue: ['A'] | |
| ifFalse: ['B']] | |
| ifFalse: ['C']); | |
| cr. | |
| switch := Dictionary new. "switch functionality" | |
| switch at: $A put: [Transcript show: 'Case A'; cr]. | |
| switch at: $B put: [Transcript show: 'Case B'; cr]. | |
| switch at: $C put: [Transcript show: 'Case C'; cr]. | |
| result := (switch at: $B) value. | |
| "************************************************************************ | |
| * Iteration statements: * | |
| ************************************************************************" | |
| | x y | | |
| x := 4. y := 1. | |
| [x > 0] whileTrue: [x := x - 1. y := y * 2]. "while true loop" | |
| [x >= 4] whileFalse: [x := x + 1. y := y * 2]. "while false loop" | |
| x timesRepeat: [y := y * 2]. "times repear loop (i := 1 to x)" | |
| 1 to: x do: [:a | y := y * 2]. "for loop" | |
| 1 to: x by: 2 do: [:a | y := y / 2]. "for loop with specified increment" | |
| #(5 4 3) do: [:a | x := x + a]. "iterate over array elements" | |
| "************************************************************************ | |
| * Character: * | |
| ************************************************************************" | |
| | x y | | |
| x := $A. "character assignment" | |
| y := x isLowercase. "test if lower case" | |
| y := x isUppercase. "test if upper case" | |
| y := x isLetter. "test if letter" | |
| y := x isDigit. "test if digit" | |
| y := x isAlphaNumeric. "test if alphanumeric" | |
| y := x isSeparator. "test if seperator char" | |
| y := x isVowel. "test if vowel" | |
| y := x digitValue. "convert to numeric digit value" | |
| y := x asLowercase. "convert to lower case" | |
| y := x asUppercase. "convert to upper case" | |
| y := x asciiValue. "convert to numeric ascii value" | |
| y := x asString. "convert to string" | |
| y := $A <= $B. "comparison" | |
| y := $A max: $B. | |
| "************************************************************************ | |
| * Symbol: * | |
| ************************************************************************" | |
| | b x y | | |
| x := #Hello. "symbol assignment" | |
| y := 'String', 'Concatenation'. "symbol concatenation (result is string)" | |
| b := x isEmpty. "test if symbol is empty" | |
| y := x size. "string size" | |
| y := x at: 2. "char at location" | |
| y := x copyFrom: 2 to: 4. "substring" | |
| y := x indexOf: $e ifAbsent: [0]. "first position of character within string" | |
| x do: [:a | Transcript show: a printString; cr]. "iterate over the string" | |
| y := x select: [:a | a > $a]. "return all elements that meet condition" | |
| y := x asString. "convert symbol to string" | |
| y := x asText. "convert symbol to text" | |
| y := x asArray. "convert symbol to array" | |
| y := x asOrderedCollection. "convert symbol to ordered collection" | |
| y := x asSortedCollection. "convert symbol to sorted collection" | |
| y := x asBag. "convert symbol to bag collection" | |
| y := x asSet. "convert symbol to set collection" | |
| "************************************************************************ | |
| * String: * | |
| ************************************************************************" | |
| | b x y | | |
| x := 'This is a string'. "string assignment" | |
| x allButFirst: 10. "returns string" | |
| x := 'String', 'Concatenation'. "string concatenation" | |
| b := x isEmpty. "test if string is empty" | |
| y := x size. "string size" | |
| y := x at: 2. "char at location" | |
| y := x copyFrom: 2 to: 4. "substring" | |
| y := x indexOf: $a ifAbsent: [0]. "first position of character within string" | |
| x := String new: 4. "allocate string object" | |
| x "set string elements" | |
| at: 1 put: $a; | |
| at: 2 put: $b; | |
| at: 3 put: $c; | |
| at: 4 put: $e. | |
| x := String with: $a with: $b with: $c with: $d. "set up to 4 elements at a time" | |
| x do: [:a | Transcript show: a printString; cr]. "iterate over the string" | |
| y := x select: [:a | a > $a]. "return all elements that meet condition" | |
| y := x asSymbol. "convert string to symbol" | |
| y := x asArray. "convert string to array" | |
| x := 'ABCD' asByteArray. "convert string to byte array" | |
| y := x asOrderedCollection. "convert string to ordered collection" | |
| y := x asSortedCollection. "convert string to sorted collection" | |
| y := x asBag. "convert string to bag collection" | |
| y := x asSet. "convert string to set collection" | |
| y := x shuffled. "randomly shuffle string" | |
| "************************************************************************ | |
| * Array: Fixed length collection * | |
| * ByteArray: Array limited to byte elements (0-255) * | |
| * WordArray: Array limited to word elements (0-2^32) * | |
| ************************************************************************" | |
| | b x y sum max | | |
| x := #[255 255 255]. "constant byte array" | |
| x := #(4 3 2 1). "literal array" | |
| x := #((1 + 2) . 3). "literal array whose first element is an array of size 3" | |
| x := { 5. 4. 3. 2 }. "dynamic array" | |
| x := Array with: 5 with: 4 with: 3 with: 2. "create array with up to 4 elements" | |
| x := Array new: 4. "allocate an array with specified size" | |
| x "set array elements" | |
| at: 1 put: 5; | |
| at: 2 put: 4; | |
| at: 3 put: 3; | |
| at: 4 put: 2. | |
| b := x isEmpty. "test if array is empty" | |
| y := x size. "array size" | |
| y := x at: 4. "get array element at index" | |
| b := x includes: 3. "test if element is in array" | |
| y := x copyFrom: 2 to: 4. "subarray" | |
| y := x indexOf: 3 ifAbsent: [0]. "first position of element within array" | |
| y := x occurrencesOf: 3. "number of times object in collection" | |
| x do: [:a | Transcript show: a printString; cr]. "iterate over the array" | |
| y := x select: [:a | a > 2]. "return collection of elements that pass test" | |
| y := x reject: [:a | a < 2]. "return collection of elements that fail test" | |
| y := x collect: [:a | a + a]. "transform each element for new collection" | |
| y := x detect: [:a | a > 3] ifNone: []. "find position of first element that passes test" | |
| sum := 0. x do: [:a | sum := sum + a]. sum. "sum array elements" | |
| sum := 0. 1 to: (x size) do: [:a | sum := sum + (x at: a)]. "sum array elements" | |
| sum := x inject: 0 into: [:a :c | a + c]. "sum array elements" | |
| max := x inject: 0 into: [:a :c | (a > c) "find max element in array" | |
| ifTrue: [a] | |
| ifFalse: [c]]. | |
| y := x shuffled. "randomly shuffle collection" | |
| y := x asArray. "convert to array" | |
| y := x asByteArray. "convert to byte array" | |
| y := x asWordArray. "convert to word array" | |
| y := x asOrderedCollection. "convert to ordered collection" | |
| y := x asSortedCollection. "convert to sorted collection" | |
| y := x asBag. "convert to bag collection" | |
| y := x asSet. "convert to set collection" | |
| "************************************************************************ | |
| * OrderedCollection: acts like an expandable array * | |
| ************************************************************************" | |
| | b x y sum max | | |
| x := OrderedCollection with: 4 with: 3 with: 2 with: 1. "create collection with up to 4 elements" | |
| x := OrderedCollection new. "allocate collection" | |
| x add: 3; add: 2; add: 1; add: 4; yourself. "add element to collection" | |
| y := x addFirst: 5. "add element at beginning of collection" | |
| y := x removeFirst. "remove first element in collection" | |
| y := x addLast: 6. "add element at end of collection" | |
| y := x removeLast. "remove last element in collection" | |
| y := x addAll: #(7 8 9). "add multiple elements to collection" | |
| y := x removeAll: #(7 8 9). "remove multiple elements from collection" | |
| x at: 2 put: 3. "set element at index" | |
| y := x remove: 5 ifAbsent: []. "remove element from collection" | |
| b := x isEmpty. "test if empty" | |
| y := x size. "number of elements" | |
| y := x at: 2. "retrieve element at index" | |
| y := x first. "retrieve first element in collection" | |
| y := x last. "retrieve last element in collection" | |
| b := x includes: 5. "test if element is in collection" | |
| y := x copyFrom: 2 to: 3. "subcollection" | |
| y := x indexOf: 3 ifAbsent: [0]. "first position of element within collection" | |
| y := x occurrencesOf: 3. "number of times object in collection" | |
| x do: [:a | Transcript show: a printString; cr]. "iterate over the collection" | |
| y := x select: [:a | a > 2]. "return collection of elements that pass test" | |
| y := x reject: [:a | a < 2]. "return collection of elements that fail test" | |
| y := x collect: [:a | a + a]. "transform each element for new collection" | |
| y := x detect: [:a | a > 3] ifNone: []. "find position of first element that passes test" | |
| sum := 0. x do: [:a | sum := sum + a]. sum. "sum elements" | |
| sum := 0. 1 to: (x size) do: [:a | sum := sum + (x at: a)]. "sum elements" | |
| sum := x inject: 0 into: [:a :c | a + c]. "sum elements" | |
| max := x inject: 0 into: [:a :c | (a > c) "find max element in collection" | |
| ifTrue: [a] | |
| ifFalse: [c]]. | |
| y := x shuffled. "randomly shuffle collection" | |
| y := x asArray. "convert to array" | |
| y := x asOrderedCollection. "convert to ordered collection" | |
| y := x asSortedCollection. "convert to sorted collection" | |
| y := x asBag. "convert to bag collection" | |
| y := x asSet. "convert to set collection" | |
| "************************************************************************ | |
| * SortedCollection: like OrderedCollection except order of elements * | |
| * determined by sorting criteria * | |
| ************************************************************************" | |
| | b x y sum max | | |
| x := SortedCollection with: 4 with: 3 with: 2 with: 1. "create collection with up to 4 elements" | |
| x := SortedCollection new. "allocate collection" | |
| x := SortedCollection sortBlock: [:a :c | a > c]. "set sort criteria" | |
| x add: 3; add: 2; add: 1; add: 4; yourself. "add element to collection" | |
| y := x removeFirst. "remove first element in collection" | |
| y := x addLast: 5. "add element at end of collection" | |
| y := x removeLast. "remove last element in collection" | |
| y := x addAll: #(6 7 8). "add multiple elements to collection" | |
| y := x removeAll: #(6 7 8). "remove multiple elements from collection" | |
| y := x remove: 5 ifAbsent: []. "remove element from collection" | |
| b := x isEmpty. "test if empty" | |
| y := x size. "number of elements" | |
| y := x at: 2. "retrieve element at index" | |
| y := x first. "retrieve first element in collection" | |
| y := x last. "retrieve last element in collection" | |
| b := x includes: 4. "test if element is in collection" | |
| y := x copyFrom: 2 to: 3. "subcollection" | |
| y := x indexOf: 3 ifAbsent: [0]. "first position of element within collection" | |
| y := x occurrencesOf: 3. "number of times object in collection" | |
| x do: [:a | Transcript show: a printString; cr]. "iterate over the collection" | |
| b := x conform: [:a | (a >= 1) & (a <= 4)]. "test if all elements meet condition" | |
| y := x select: [:a | a > 2]. "return collection of elements that pass test" | |
| y := x reject: [:a | a < 2]. "return collection of elements that fail test" | |
| y := x collect: [:a | a + a]. "transform each element for new collection" | |
| y := x detect: [:a | a > 3] ifNone: []. "find position of first element that passes test" | |
| sum := 0. x do: [:a | sum := sum + a]. sum. "sum elements" | |
| sum := 0. 1 to: (x size) do: [:a | sum := sum + (x at: a)]. "sum elements" | |
| sum := x inject: 0 into: [:a :c | a + c]. "sum elements" | |
| max := x inject: 0 into: [:a :c | (a > c) "find max element in collection" | |
| ifTrue: [a] | |
| ifFalse: [c]]. | |
| y := x asArray. "convert to array" | |
| y := x asOrderedCollection. "convert to ordered collection" | |
| y := x asSortedCollection. "convert to sorted collection" | |
| y := x asBag. "convert to bag collection" | |
| y := x asSet. "convert to set collection" | |
| "************************************************************************ | |
| * Bag: like OrderedCollection except elements are in no * | |
| * particular order * | |
| ************************************************************************" | |
| | b x y sum max | | |
| x := Bag with: 4 with: 3 with: 2 with: 1. "create collection with up to 4 elements" | |
| x := Bag new. "allocate collection" | |
| x add: 4; add: 3; add: 1; add: 2; yourself. "add element to collection" | |
| x add: 3 withOccurrences: 2. "add multiple copies to collection" | |
| y := x addAll: #(7 8 9). "add multiple elements to collection" | |
| y := x removeAll: #(7 8 9). "remove multiple elements from collection" | |
| y := x remove: 4 ifAbsent: []. "remove element from collection" | |
| b := x isEmpty. "test if empty" | |
| y := x size. "number of elements" | |
| b := x includes: 3. "test if element is in collection" | |
| y := x occurrencesOf: 3. "number of times object in collection" | |
| x do: [:a | Transcript show: a printString; cr]. "iterate over the collection" | |
| y := x select: [:a | a > 2]. "return collection of elements that pass test" | |
| y := x reject: [:a | a < 2]. "return collection of elements that fail test" | |
| y := x collect: [:a | a + a]. "transform each element for new collection" | |
| y := x detect: [:a | a > 3] ifNone: []. "find position of first element that passes test" | |
| sum := 0. x do: [:a | sum := sum + a]. sum. "sum elements" | |
| sum := x inject: 0 into: [:a :c | a + c]. "sum elements" | |
| max := x inject: 0 into: [:a :c | (a > c) "find max element in collection" | |
| ifTrue: [a] | |
| ifFalse: [c]]. | |
| y := x asOrderedCollection. "convert to ordered collection" | |
| y := x asSortedCollection. "convert to sorted collection" | |
| y := x asBag. "convert to bag collection" | |
| y := x asSet. "convert to set collection" | |
| "************************************************************************ | |
| * Set: like Bag except duplicates not allowed * | |
| * IdentitySet: uses identity test (== rather than =) * | |
| ************************************************************************" | |
| | b x y sum max | | |
| x := Set with: 4 with: 3 with: 2 with: 1. "create collection with up to 4 elements" | |
| x := Set new. "allocate collection" | |
| x add: 4; add: 3; add: 1; add: 2; yourself. "add element to collection" | |
| y := x addAll: #(7 8 9). "add multiple elements to collection" | |
| y := x removeAll: #(7 8 9). "remove multiple elements from collection" | |
| y := x remove: 4 ifAbsent: []. "remove element from collection" | |
| b := x isEmpty. "test if empty" | |
| y := x size. "number of elements" | |
| x includes: 4. "test if element is in collection" | |
| x do: [:a | Transcript show: a printString; cr]. "iterate over the collection" | |
| y := x select: [:a | a > 2]. "return collection of elements that pass test" | |
| y := x reject: [:a | a < 2]. "return collection of elements that fail test" | |
| y := x collect: [:a | a + a]. "transform each element for new collection" | |
| y := x detect: [:a | a > 3] ifNone: []. "find position of first element that passes test" | |
| sum := 0. x do: [:a | sum := sum + a]. sum. "sum elements" | |
| sum := x inject: 0 into: [:a :c | a + c]. "sum elements" | |
| max := x inject: 0 into: [:a :c | (a > c) "find max element in collection" | |
| ifTrue: [a] | |
| ifFalse: [c]]. | |
| y := x asArray. "convert to array" | |
| y := x asOrderedCollection. "convert to ordered collection" | |
| y := x asSortedCollection. "convert to sorted collection" | |
| y := x asBag. "convert to bag collection" | |
| y := x asSet. "convert to set collection" | |
| "************************************************************************ | |
| * Interval: * | |
| ************************************************************************" | |
| | b x y sum max | | |
| x := Interval from: 5 to: 10. "create interval object" | |
| x := 5 to: 10. | |
| x := Interval from: 5 to: 10 by: 2. "create interval object with specified increment" | |
| x := 5 to: 10 by: 2. | |
| b := x isEmpty. "test if empty" | |
| y := x size. "number of elements" | |
| x includes: 9. "test if element is in collection" | |
| x do: [:k | Transcript show: k printString; cr]. "iterate over interval" | |
| y := x select: [:a | a > 7]. "return collection of elements that pass test" | |
| y := x reject: [:a | a < 2]. "return collection of elements that fail test" | |
| y := x collect: [:a | a + a]. "transform each element for new collection" | |
| y := x detect: [:a | a > 3] ifNone: []. "find position of first element that passes test" | |
| sum := 0. x do: [:a | sum := sum + a]. sum. "sum elements" | |
| sum := 0. 1 to: (x size) do: [:a | sum := sum + (x at: a)]. "sum elements" | |
| sum := x inject: 0 into: [:a :c | a + c]. "sum elements" | |
| max := x inject: 0 into: [:a :c | (a > c) "find max element in collection" | |
| ifTrue: [a] | |
| ifFalse: [c]]. | |
| y := x asArray. "convert to array" | |
| y := x asOrderedCollection. "convert to ordered collection" | |
| y := x asSortedCollection. "convert to sorted collection" | |
| y := x asBag. "convert to bag collection" | |
| y := x asSet. "convert to set collection" | |
| "************************************************************************ | |
| * Associations: * | |
| ************************************************************************" | |
| | x y | | |
| x := #myVar->'hello'. | |
| y := x key. | |
| y := x value. | |
| "************************************************************************ | |
| * Dictionary: * | |
| * IdentityDictionary: uses identity test (== rather than =) * | |
| ************************************************************************" | |
| | b x y | | |
| x := Dictionary new. "allocate collection" | |
| x add: #a->4; add: #b->3; add: #c->1; add: #d->2; yourself. "add element to collection" | |
| x at: #e put: 3. "set element at index" | |
| b := x isEmpty. "test if empty" | |
| y := x size. "number of elements" | |
| y := x at: #a ifAbsent: []. "retrieve element at index" | |
| y := x keyAtValue: 3 ifAbsent: []. "retrieve key for given value with error block" | |
| y := x removeKey: #e ifAbsent: []. "remove element from collection" | |
| b := x includes: 3. "test if element is in values collection" | |
| b := x includesKey: #a. "test if element is in keys collection" | |
| y := x occurrencesOf: 3. "number of times object in collection" | |
| y := x keys. "set of keys" | |
| y := x values. "bag of values" | |
| x do: [:a | Transcript show: a printString; cr]. "iterate over the values collection" | |
| x keysDo: [:a | Transcript show: a printString; cr]. "iterate over the keys collection" | |
| x associationsDo: [:a | Transcript show: a printString; cr]."iterate over the associations" | |
| x keysAndValuesDo: [:aKey :aValue | Transcript "iterate over keys and values" | |
| show: aKey printString; space; | |
| show: aValue printString; cr]. | |
| y := x select: [:a | a > 2]. "return collection of elements that pass test" | |
| y := x reject: [:a | a < 2]. "return collection of elements that fail test" | |
| y := x collect: [:a | a + a]. "transform each element for new collection" | |
| y := x detect: [:a | a > 3] ifNone: []. "find position of first element that passes test" | |
| sum := 0. x do: [:a | sum := sum + a]. sum. "sum elements" | |
| sum := x inject: 0 into: [:a :c | a + c]. "sum elements" | |
| max := x inject: 0 into: [:a :c | (a > c) "find max element in collection" | |
| ifTrue: [a] | |
| ifFalse: [c]]. | |
| y := x asArray. "convert to array" | |
| y := x asOrderedCollection. "convert to ordered collection" | |
| y := x asSortedCollection. "convert to sorted collection" | |
| y := x asBag. "convert to bag collection" | |
| y := x asSet. "convert to set collection" | |
| "************************************************************************ | |
| * Internal Stream: * | |
| ************************************************************************" | |
| | b x ios | | |
| ios := ReadStream on: 'Hello read stream'. | |
| ios := ReadStream on: 'Hello read stream' from: 1 to: 5. | |
| [(x := ios nextLine) notNil] | |
| whileTrue: [Transcript show: x; cr]. | |
| ios position: 3. | |
| ios position. | |
| x := ios next. | |
| x := ios peek. | |
| x := ios contents. | |
| b := ios atEnd. | |
| ios := ReadWriteStream on: 'Hello read stream'. | |
| ios := ReadWriteStream on: 'Hello read stream' from: 1 to: 5. | |
| ios := ReadWriteStream with: 'Hello read stream'. | |
| ios := ReadWriteStream with: 'Hello read stream' from: 1 to: 10. | |
| ios position: 0. | |
| [(x := ios nextLine) notNil] | |
| whileTrue: [Transcript show: x; cr]. | |
| ios position: 6. | |
| ios position. | |
| ios nextPutAll: 'Chris'. | |
| x := ios next. | |
| x := ios peek. | |
| x := ios contents. | |
| b := ios atEnd. | |
| "************************************************************************ | |
| * FileStream: * | |
| ************************************************************************" | |
| | b x ios | | |
| ios := FileStream newFileNamed: 'ios.txt'. | |
| ios nextPut: $H; cr. | |
| ios nextPutAll: 'Hello File'; cr. | |
| 'Hello File' printOn: ios. | |
| 'Hello File' storeOn: ios. | |
| ios close. | |
| ios := FileStream oldFileNamed: 'ios.txt'. | |
| [(x := ios nextLine) notNil] | |
| whileTrue: [Transcript show: x; cr]. | |
| ios position: 3. | |
| x := ios position. | |
| x := ios next. | |
| x := ios peek. | |
| b := ios atEnd. | |
| ios close. | |
| "************************************************************************ | |
| * Files: * | |
| ************************************************************************" | |
| | p m hello | | |
| p := FileLocator home. "user's home directory" | |
| p := FileLocator root. "file system root" | |
| p pathString. "file path string" | |
| p parent pathString. "path of the parent folder" | |
| m := FileLocator home / 'Music'. "handle to ~/Music" | |
| m exists. "test if file/folder exists" | |
| m isDirectory. "test if handle is a folder" | |
| m allChildrenMatching: '.mp3'. "finding all mp3 files in folder" | |
| p := 'pharo5.image' asFileReference. "handle to pharo.image file" | |
| p isFile. "test if handle is a file" | |
| p basename. "obtain filename without path" | |
| hello := 'hello.txt' asFileReference. | |
| hello writeStreamDo: [ :stream | "write to file" | |
| stream nextPutAll: 'Hello World']. | |
| hello readStreamDo: [ :stream | stream contents ]. "read from file" | |
| "************************************************************************ | |
| * Date: * | |
| ************************************************************************" | |
| | x y | | |
| x := Date today. "create date for today" | |
| x := Date dateAndTimeNow. "create date from current time/date" | |
| x := Date readFromString: '01/02/1999'. "create date from formatted string" | |
| x := Date newDay: 12 month: #July year: 1999. "create date from parts" | |
| x := Date fromDays: 36000. "create date from elapsed days since 1/1/1901" | |
| y := Date dayOfWeek: #Monday. "day of week as int (1-7)" | |
| y := Date indexOfMonth: #January. "month of year as int (1-12)" | |
| y := Date daysInMonth: 2 forYear: 1996. "day of month as int (1-31)" | |
| y := Date daysInYear: 1996. "days in year (365|366)" | |
| y := Date nameOfDay: 1. "weekday name (#Monday,...)" | |
| y := Date nameOfMonth: 1. "month name (#January,...)" | |
| y := x weekday. "day of week (#Monday,...)" | |
| y := x previous: #Monday. "date for previous day of week" | |
| y := x dayOfMonth. "day of month (1-31)" | |
| y := x day. "day of year (1-366)" | |
| y := x firstDayOfMonth. "day of year for first day of month" | |
| y := x monthName. "month of year (#January,...)" | |
| y := x monthIndex. "month of year (1-12)" | |
| y := x daysInMonth. "days in month (1-31)" | |
| y := x year. "year (19xx)" | |
| y := x daysInYear. "days in year (365|366)" | |
| y := x daysLeftInYear. "days left in year (364|365)" | |
| y := x asSeconds. "seconds elapsed since 1/1/1901" | |
| y := x addDays: 10. "add days to date object" | |
| y := x subtractDays: 10. "subtract days to date object" | |
| y := x subtractDate: (Date today). "subtract date (result in days)" | |
| y := x printFormat: #(2 1 3 $/ 1 1). "print formatted date" | |
| b := (x <= Date today). "comparison" | |
| "************************************************************************ | |
| * Time: * | |
| ************************************************************************" | |
| | x y | | |
| x := Time now. "create time from current time" | |
| x := Time now asdateAndTime. "create time from current time/date" | |
| x := Time readFromString: '3:47:26 pm'. "create time from formatted string" | |
| x := Time fromSeconds: (60 * 60 * 4). "create time from elapsed time from midnight" | |
| y := Time millisecondClockValue. "milliseconds since midnight" | |
| y := Time totalSeconds. "total seconds since 1/1/1901" | |
| y := x seconds. "seconds past minute (0-59)" | |
| y := x minutes. "minutes past hour (0-59)" | |
| y := x hours. "hours past midnight (0-23)" | |
| y := x addTime: (Time now). "add time to time object" | |
| y := x subtractTime: (Time now). "subtract time to time object" | |
| y := x asSeconds. "convert time to seconds" | |
| x := Time millisecondsToRun: [ "timing facility" | |
| 1 to: 1000 do: [:index | y := 3.14 * index]]. | |
| b := (x <= Time now). "comparison" | |
| "************************************************************************ | |
| * Point: * | |
| ************************************************************************" | |
| | pt x y | | |
| pt := 200@100. "obtain a new point" | |
| x := pt x. "x coordinate" | |
| y := pt y. "y coordinate" | |
| pt := 200@100 negated. "negates x and y" | |
| pt := (-200@ -100) abs. "absolute value of x and y" | |
| pt := (200.5@100.5) rounded. "round x and y" | |
| pt := (200.5@100.5) truncated. "truncate x and y" | |
| pt := 200@100 + 100. "add scale to both x and y" | |
| pt := 200@100 - 100. "subtract scale from both x and y" | |
| pt := 200@100 * 2. "multiply x and y by scale" | |
| pt := 200@100 / 2. "divide x and y by scale" | |
| pt := 200@100 // 2. "divide x and y by scale" | |
| pt := 200@100 \\ 3. "remainder of x and y by scale" | |
| pt := (200@100) + (50@25). "add points" | |
| pt := (200@100) – (50@25). "subtract points" | |
| pt := (200@100) * (3@4). "multiply points" | |
| pt := (200@100) // (3@4). "divide points" | |
| pt := 200@100 max: 50@200. "max x and y" | |
| pt := 200@100 min: 50@200. "min x and y" | |
| pt := 20@5 dotProduct: 10@2. "sum of product (x1*x2 + y1*y2)" | |
| "************************************************************************ | |
| * Rectangle: * | |
| ************************************************************************" | |
| Rectangle fromUser. | |
| "************************************************************************ | |
| * Pen: * | |
| ************************************************************************" | |
| Gofer it | |
| squeaksource: 'PharoNonCorePackages'; | |
| package: 'BitBltPen'; | |
| load. | |
| | myPen | | |
| Display restoreAfter: [ | |
| Display fillWhite. | |
| myPen := Pen new. "get graphic pen" | |
| myPen squareNib: 1. | |
| myPen color: (Color blue). "set pen color" | |
| myPen home. "position pen at center of display" | |
| myPen up. "makes nib unable to draw" | |
| myPen down. "enable the nib to draw" | |
| myPen north. "points direction towards top" | |
| myPen turn: -180. "add specified degrees to direction" | |
| myPen direction. "get current angle of pen" | |
| myPen go: 50. "move pen specified number of pixels" | |
| myPen location. "get the pen position" | |
| myPen goto: 200@200. "move to specified point" | |
| myPen place: 250@250. "move to specified point without drawing" | |
| myPen print: 'Hello World' withFont: (TextStyle default fontAt: 1). | |
| Display extent. "get display width@height" | |
| Display width. "get display width" | |
| Display height. "get display height" | |
| ]. | |
| "************************************************************************ | |
| * Dynamic Message Calling/Compiling: * | |
| ************************************************************************" | |
| | receiver message result argument keyword1 keyword2 argument1 argument2 | | |
| "unary message" | |
| receiver := 5. | |
| message := 'factorial' asSymbol. | |
| result := receiver perform: message. | |
| result := Compiler evaluate: ((receiver storeString), ' ', message). | |
| result := (Message new setSelector: message arguments: #()) sentTo: receiver. | |
| "binary message" | |
| receiver := 1. | |
| message := '+' asSymbol. | |
| argument := 2. | |
| result := receiver perform: message withArguments: (Array with: argument). | |
| result := Compiler evaluate: ((receiver storeString), ' ', message, ' ', (argument storeString)). | |
| result := (Message new setSelector: message arguments: (Array with: argument)) sentTo: receiver. | |
| "keyword messages" | |
| receiver := 12. | |
| keyword1 := 'between:' asSymbol. | |
| keyword2 := 'and:' asSymbol. | |
| argument1 := 10. | |
| argument2 := 20. | |
| result := receiver | |
| perform: (keyword1, keyword2) asSymbol | |
| withArguments: (Array with: argument1 with: argument2). | |
| result := Compiler evaluate: | |
| ((receiver storeString), ' ', keyword1, (argument1 storeString) , ' ', keyword2, (argument2 storeString)). | |
| result := (Message | |
| new | |
| setSelector: (keyword1, keyword2) asSymbol | |
| arguments: (Array with: argument1 with: argument2)) | |
| sentTo: receiver. | |
| "************************************************************************ | |
| * class/meta-class: * | |
| ************************************************************************" | |
| | b x | | |
| x := String name. "class name" | |
| x := String category. "organization category" | |
| x := String comment. "class comment" | |
| x := String kindOfSubclass. "subclass type - subclass: variableSubclass, etc" | |
| x := String definition. "class definition" | |
| x := String instVarNames. "immediate instance variable names" | |
| x := String allInstVarNames. "accumulated instance variable names" | |
| x := String classVarNames. "immediate class variable names" | |
| x := String allClassVarNames. "accumulated class variable names" | |
| x := String sharedPools. "immediate dictionaries used as shared pools" | |
| x := String allSharedPools. "accumulated dictionaries used as shared pools" | |
| x := String selectors. "message selectors for class" | |
| x := String sourceCodeAt: #capitalized. "source code for specified method" | |
| x := String allInstances. "collection of all instances of class" | |
| x := String superclass. "immediate superclass" | |
| x := String allSuperclasses. "accumulated superclasses" | |
| x := String withAllSuperclasses. "receiver class and accumulated superclasses" | |
| x := String subclasses. "immediate subclasses" | |
| x := String allSubclasses. "accumulated subclasses" | |
| x := String withAllSubclasses. "receiver class and accumulated subclasses" | |
| b := String instSize. "number of named instance variables" | |
| b := String isFixed. "true if no indexed instance variables" | |
| b := String isVariable. "true if has indexed instance variables" | |
| b := String isPointers. "true if index instance vars contain objects" | |
| b := String isBits. "true if index instance vars contain bytes/words" | |
| b := String isBytes. "true if index instance vars contain bytes" | |
| b := String isWords. "true if index instance vars contain words" | |
| Object withAllSubclasses size. "get total number of class entries" | |
| "************************************************************************ | |
| * Exceptions: * | |
| ************************************************************************" | |
| [ 1/0 ] on: ZeroDivide do: [ :ex | Transcript show: ex ]. "installing an exception handler" | |
| Warning signal: 'watch out!'. "raising an exception" | |
| [ 1/0 ] ensure: [ Transcript show: 'exception' ]. "always execute last block" | |
| [ 1/0 ] ifCurtailed: [ Transcript show: 'exception' ]. "execute last block only if fail" | |
| "************************************************************************ | |
| * Debugging: * | |
| ************************************************************************" | |
| | x | | |
| x yourself. "returns receiver" | |
| String browse. "browse specified class" | |
| x inspect. "open object inspector window" | |
| x confirm: 'Is this correct?'. | |
| x halt. "breakpoint to open debugger window" | |
| x halt: 'Halt message'. | |
| x notify: 'Notify text'. | |
| x error: 'Error string'. "open up error window with title" | |
| x doesNotUnderstand: #cmrMessage. "flag message is not handled" | |
| x shouldNotImplement. "flag message should not be implemented" | |
| x subclassResponsibility. "flag message as abstract" | |
| x errorImproperStore. "flag an improper store into indexable object" | |
| x errorNonIntegerIndex. "flag only integers should be used as index" | |
| x errorSubscriptBounds. "flag subscript out of bounds" | |
| x primitiveFailed. "system primitive failed" | |
| "************************************************************************ | |
| * Misc. * | |
| ************************************************************************" | |
| | x | | |
| 'Hello World' asMorph openInWindow. | |
| UIManager default message: 'Hello Pharo'. "display message" | |
| x := UIManager default request: 'Enter value:'. "prompt user for input using a flexible UI dispatcher" | |
| (ZnEasy getPng: 'http://pharo.org/web/files/pharo.png') | |
| asMorph openInWindow. "get the Pharo logo" |
The line
UIManager default message: 'Hello Pharo.'
needs a period at the end, outside of the quoted string:
UIManager default message: 'Hello Pharo.' .
It's required to end the statement. (The period inside the quotes is just a character in the string.)
thank you @tbrunz
This is a great resource! I have found it very helpful. Thank you!
I would love a guide like this to other programming languages. Do you know if there is a similar guide for JavaScript? Or any other languages?
Thanks! Not that I am aware of but check GitHub for cheatsheets ... there's good stuff out there...
Hi jdevoo
I would like to take your guide as input for a Pharo internal documentation.
Is it ok for you?
S
Hi jdevoo I would like to take your guide as input for a Pharo internal documentation. Is it ok for you? S
Yes Stephane! With great pleasure! :-)
Hey there, shouldnt the collection-injects use the 'max:' function of number instead of implementing it on its own?
[instead of:
(a > c)
ifTrue: [a]
ifFalse: [c]
use:
a max: c ]
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I tried to run the Misc. code in the Pharo playground but got error
End of Statement list encountered ->at this line:x := UIManager default request: 'Enter value:'.