[Python-Dev] PEP 3103: A Switch/Case Statement (original) (raw)

Fredrik Lundh fredrik at pythonware.com
Thu Jun 29 16:38:20 CEST 2006

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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