[Python-Dev] PEP 3103: A Switch/Case Statement

[Fredrik Lundh]

Eric Sumner wrote:

>> You mean something like this?:
>>
>>    switch x in colours:
>>      case RED:
>>          # whatever
>>      case GREEN:
>>          # whatever
>>      case BLUE:
>>          # whatever
>>
>> I think Guido's right. It doesn't solve the underlying problem because the
>> compiler still has to figure out how to build a dispatch table from the
>> possible values in colours to the actual bytecode offsets of the cases.
>
> To implement this, you actually need two lookup tables: one particular
> to the switch that maps labels to bytecode offsets, and one in the
> dispatch table to map values to labels.  The former is built when the
> switch is compiled, and the latter is built wherever the dispatch
> table is defined.  Each lookup is still O(1), so the whole operation
> remains O(1).

what's a "label" ?

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