5385 inGroupsOf:n detect:anNArgBlock thenDo:anotherNArgBlock ifNone:exceptionValue

  5386     "evaluate the argument, anNArgBlock for every group of n elements in the collection,

  5387      until the block returns true. Then deliver the to anotherNArgBlock and return

  5388      that block's result. If none matches, return the valeu from exceptionValue.

  5389      An error will be reported, if the number of elements in the receiver

  5390      is not a multiple of n.

  5391      This is similar to slicesOf:detect:, but here, an N-arg block is expected."

  5392 

  5393     |stop argVector|

  5394 

  5395     stop := self size.

  5396 

  5397     "/ the reason for inlining the cases for 2/3 args is to avoid the temporary object creation, and to    

  5398     "/ allow for the compiler (jitter) to generate better code for the block-call

  5399     n == 2 ifTrue:[

  5400         1 to:stop by:2 do:[:index |

  5401             |a1 a2|

  5402 

  5403             a1 := self at:index.

  5404             a2 := self at:index+1.

  5405             (anNArgBlock value:a1 value:a2) ifTrue:[

  5406                 ^ anotherNArgBlock value:a1 value:a2

  5407             ].

  5408         ].

  5409         ^ exceptionValue value.

  5410     ].

  5411     n == 3 ifTrue:[

  5412         1 to:stop by:3 do:[:index |

  5413             |a1 a2 a3|

  5414 

  5415             a1 := self at:index.

  5416             a2 := self at:index+1.

  5417             a3 := self at:index+2.

  5418             (anNArgBlock value:a1 value:a2 value:a3) ifTrue:[

  5419                 ^ anotherNArgBlock value:a1 value:a2 value:a3

  5420             ].

  5421         ].

  5422         ^ exceptionValue value.

  5423     ].

  5424 

  5425     argVector := Array new:n.

  5426     1 to:stop by:n do:[:index |

  5427         argVector replaceFrom:1 to:n with:self startingAt:index.

  5428         (anNArgBlock valueWithArguments:argVector) ifTrue:[

  5429             ^ anotherNArgBlock valueWithArguments:argVector

  5430         ].

  5431     ].

  5432     ^ exceptionValue value.

  5433 

  5434     "

  5435      #(1 one 2 two 3 three 4 four 5 five 6 six)

  5436          inGroupsOf:2 detect:[:num :sym | num > 3]

  5437          thenDo:[:num :sym | sym] ifNone:'ouch'   

  5438 

  5439      #(1 one 2 two 3 three 4 four 5 five 6 six)

  5440          inGroupsOf:2 detect:[:num :sym | num > 99]

  5441          thenDo:[:num :sym | sym] ifNone:'ouch'      

  5442     "

  5443 

  5444     "Modified: / 27-10-2006 / 10:07:02 / cg"

  5445 !

  5446