here - Stefan-Marr.de

4.2. SOM: Simple Object Machine
1 SOMInterpreter = (
2 | frame universe currentBytecode |
3
4 currentObject = ( ^ ( frame outerContext ) currentObject )
5
6 doPopField = (
7 self currentObject
8 fieldAtIndex : currentBytecode fieldIndex
9 put : frame pop )
10
11 doPushField = (
12 frame push :
13 ( self currentObject
14 fieldAtIndex : currentBytecode fieldIndex ))
15
16 doSend = (
17 | receiver |
18 receiver := frame stackElementAtIndex :
19 currentBytecode selector numArgs + 1.
20 ^ self performSend : currentBytecode selector
21 to: receiver
22 lookupCls : receiver class )
23
24 doSuperSend = (
25 | receiver superClass |
26 receiver := frame stackElementAtIndex :
27 currentBytecode selector numArgs + 1.
28 " Determine super in the context of the correct method ."
29 superClass := frame outerContext method holder superClass .
30 ^ self performSend : currentBytecode selector
31 to: receiver
32 lookupCls : superClass )
33
34 performSend : selector to: receiver lookupCls : cls = (
35 ^ self send : selector toClass : cls )
36
37 send : selector toClass : cls = (
38 ( cls lookupInvokable : selector )
39 ifNotNilDo : [: invokable | invokable invokeInFrame : frame ]
40 ifNil : [ self sendDoesNotUnderstand : selector ] )
41 " ... ")
Listing 4.5: Basics of the SOM Interpreter
97