Please refer to the Find-Primes example before starting with this example.
First, define the CnC graph for the partition string example:
| Code Block |
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| title | PartitionString.cnc |
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| borderStyle | solid |
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<string singletonTag>;
<string spanTags>;
[string->string input];
[string->string span];
[string->string results];
<singletonTag> :: (python createSpan);
<spanTags> :: (python processSpan);
// program inputs and outputs
env -> [input];
env -> <singletonTag>;
[results] -> env;
// producer/consumer relations
[input] -> (createSpan) -> <spanTags>, [span];
[span] -> (processSpan) -> [results];
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This graph is a little more interesting than the Find-Primes example since it has two Steps: createSpan and processSpan. createSpan produces Items for the span Item Collection. This in turn trigger the prescription of the processSpan step which writes results to the results Item Collection. The environment reads off these values from the results Item Collection.
Next, run the CnC-Python translator:
| Code Block |
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cnc_t PartitionString.cnc
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Next, we need to provide the python implementations for the Steps using the generated templates (as explained in the Find-Primes example ). Note the implementation of the createAwaitsList function in both the python Step classes which defines the input dependences on values from the Item Collections.
| Code Block |
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| title | userPartitionStringApp.py |
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| borderStyle | solid |
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class Application:
@staticmethod
def onStart(args, input, singletonTag):
# TODO fill out the body of the function
# e.g. operation on output item collections: anItemCollection.put(aTag, aValue)
# e.g. operation on tag collections: aTagCollection.putTag(aTag)
if len(args) > 0:
firstArg = args[0]
print("py: processing " + firstArg)
input.put(firstArg, firstArg)
singletonTag.putTag(firstArg)
else:
print("py: usage PartitionStringMain <the_string_to_process>")
@staticmethod
def onEnd(results):
# e.g. operation on input item collections: anItemCollection.get(aTag)
# e.g. operation on input item collections: anItemCollection.printContents()
results.printContents()
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| Code Block |
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| title | userCreateSpanStep.py |
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| borderStyle | solid |
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class CreateSpanStep:
@staticmethod
def createAwaitsList(tupleContainer, tag , inInput):
# TODO fill out the body of the function
# e.g. tupleContainer.add(itemCollection, tagValue)
# e.g. operation on item collections: anItemCollection.get(aTag)
tupleContainer.add(inInput, tag)
@staticmethod
def compute(tag , inInput, ctrlSpanTags, outSpan):
# TODO fill out the body of the function
# e.g. operation on input item collections: anItemCollection.get(aTag)
# e.g. operation on output item collections: anItemCollection.put(aTag, aValue)
# e.g. operation on tag collections: aTagCollection.putTag(aTag)
def computeRun(x, y):
if len(x) == 0:
return [y]
else:
curRun = x[-1]
if curRun[-1] == y:
x[-1] = curRun + y
return x
else:
x.append(y)
return x
inStrVal = inInput.get(tag)
inList = reduce(computeRun, inStrVal, [])
for spanStr in inList:
outSpan.put(spanStr, spanStr)
ctrlSpanTags.putTag(spanStr)
return True
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| Code Block |
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| title | userProcessSpanStep.py |
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| borderStyle | solid |
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class ProcessSpanStep:
@staticmethod
def createAwaitsList(tupleContainer, tag , inSpan):
# e.g. tupleContainer.add(itemCollection, tagValue)
# e.g. operation on item collections: anItemCollection.get(aTag)
tupleContainer.add(inSpan, tag)
@staticmethod
def compute(tag , inSpan, outResults):
# e.g. operation on input item collections: anItemCollection.get(aTag)
# e.g. operation on output item collections: anItemCollection.put(aTag, aValue)
# e.g. operation on tag collections: aTagCollection.putTag(aTag)
try:
inStr = inSpan.get(tag)
if len(inStr) % 2 != 0:
outResults.put(inStr, inStr)
return True
except Error:
print("py: NativeProcessSpanStep.compute error!")
return False
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Running this program with an input of lllllllllaaaaaaaammmmmmmeeeeeeeeeeeeeee should produce the following output:
| Code Block |
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Running PartitionStringMain
Starting PartitionStringMain...
...
py: processing lllllllllaaaaaaaammmmmmmeeeeeeeeeeeeeee
...
Contents of py:PartitionString.ResultsItemCollection [size=3]
'eeeeeeeeeeeeeee' = eeeeeeeeeeeeeee
'lllllllll' = lllllllll
'mmmmmmm' = mmmmmmm
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