Category:Smalltalk: Difference between revisions

<lang smalltalk>1000 factorial "send the 'factorial' message to the integer receiver"

a factorial even "send the 'factorial' message to whatever "'a"' refers to, then send 'even' to whatever that returned"

a + 1 "send a '+' message, passing the argument '1' to whatever 'a' refers to"

(a + 1) squared "send '+' to 'a', then send 'squared' to whatever we get from it"

a , b "send the (binary) ',' message, which does collection-concatenation (arrays, strings, etc)"

arr at:1 put:'foo' "send the 'at:put:' message to 'arr', passing two arguments, the integer '1' and a string"

a > b ifTrue: [ a print ] "send the 'ifTrue:' message to whatever 'a > b' returned (a boolean, usually), passing a block closure as argument. The implementation of boolean will either evaluate or not evaluate the passed block's code"

a > b ifTrue: [ a ] ifFalse: [b] "send 'ifTrue:ifFalse:' to the object returned by 'a > b', passing two block closures as arguments. The 'ifTrue:ifFalse:' method will evaluate one of them and return that block's return value as its own return value"

b := [ ... somCode... ]. "assign a block to the variable 'b'"

b value "evaluate the block's code (call the lambda closure)"

b2 value:123 "evaluate another block's code, passing anone argument"</lang>