Hi all,


I am curious to know whether the Squeak Context model provides any operation to swap the latest two elements from the stack. Something like:


doSwap

    | first second |

    first := self pop.

    second := self pop.

    self push: first.

    self push: second.

If it exists, I could not find it yet. If it does not exist, would you see any need to implement it (for both VM & simulation, of course)?


To me, this appears to be the most performant approach to implement a parametrized #caseError:<http://forum.world.st/Problems-with-caseError-tp5111930p5112251.html>. Something like:


81 <75> pushConstant: 0

82 <88> dup

83 <76> pushConstant: 1

84 <B6> send: =

85 <9A> jumpFalse: 89

86 <87> pop

87 <22> pushConstant: #one

88 <96> jumpTo: 97

89 <77> pushConstant: 2

90 <B6> send: =

91 <99> jumpFalse: 94

92 <21> pushConstant: #two

93 <91> jumpTo: 97

94 <70> self

95 <xx> swap

96 <D0> send: caseError:

97 <87> pop

Otherwise, we would need an extra temporary variable here.
Looking forward to your answers.


Best,

Christoph
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