演算子(みたいなもの)

当たり前すぎて、今まで注意してみたことがなかった。

| a b |
a := 20.
b := 6.
Transcript
	show: 'arithmetic operator -------'; cr;
	show: (a + b) printString; cr;	"和"
	show: (a - b) printString; cr;	"差"
	show: (a * b) printString; cr;	"積"
	show: (a / b) printString; cr;	"Integer的ななにか or Fraction"
	show: (a // b) printString; cr;	"商"
	show: (a \\ b) printString; cr;	"剰余"
	show: (a @ b) printString; cr;	"Point"
	show: (a -> b) printString; cr;	"Association"
	cr.

a := 1.
b := 1.
Transcript
	show: 'comparing operator (number) -------'; cr;
	show: (a = b) printString; cr;
	show: (a == b) printString; cr;
	show: (a ~= b) printString; cr;
	show: (a ~~ b) printString; cr;
	cr.

a := 'abc'.
b := 'abc'.
Transcript
	show: 'comparing operator (string) -------'; cr;
	show: (a = b) printString; cr;
	show: (a == b) printString; cr;
	show: (a ~= b) printString; cr;
	show: (a ~~ b) printString; cr;
	cr.

他にも、算術演算子で#\\\なんてのもあった。
割り算とか剰余とかがもっとややこしかったように思ったけど、それはHaskellの話だっけか。
文字列の#==が、SqueakとVisualWorksでは結果が異なる。というか、Squeakでtrueが返ってくるのはなんでか。

| a aLiteral aShallow aDeep |
a := 'abcde'.
aLiteral := 'abcde'.
aShallow := a shallowCopy.
aDeep := a deepCopy.	"VW => #dcopy"

Transcript
	clear;
	show: a identityHash printString; cr;
	show: aLiteral identityHash printString; cr;
	show: aShallow identityHash printString; cr;
	show: aDeep identityHash printString; cr;
	show: (a == aLiteral) printString; cr;
	show: (a == aShallow) printString; cr;
	show: (a == aDeep) printString; cr;
	cr.

a := #abcdefg.
aLiteral := #abcdefg.
aShallow := a shallowCopy.
aDeep := a deepCopy.	"VW => #dcopy"

Transcript
	show: '-----------------------------------'; cr;
	show: a identityHash printString; cr;
	show: aLiteral identityHash printString; cr;
	show: aShallow identityHash printString; cr;
	show: aDeep identityHash printString; cr;
	show: (a == aLiteral) printString; cr;
	show: (a == aShallow) printString; cr;
	show: (a == aDeep) printString; cr;
	cr.

リテラルが同一だった場合の動作が予想外な感じ。