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Diffstat (limited to 'docs/devel_guide_src/errorHandling.tex')
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diff --git a/docs/devel_guide_src/errorHandling.tex b/docs/devel_guide_src/errorHandling.tex new file mode 100755 index 0000000..02079d5 --- /dev/null +++ b/docs/devel_guide_src/errorHandling.tex @@ -0,0 +1,309 @@ +\section{Directives: Error Handling} +\label{errorHandling} + + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\subsection{\#try and \#raise} +\label{errorHandling.try} + +The template: +\begin{verbatim} +#import traceback +#try +#raise RuntimeError +#except RuntimeError +A runtime error occurred. +#end try + +#try +#raise RuntimeError("Hahaha!") +#except RuntimeError +#echo $sys.exc_info()[1] +#end try + +#try +#echo 1/0 +#except ZeroDivisionError +You can't divide by zero, idiot! +#end try +\end{verbatim} + +The output: +\begin{verbatim} +A runtime error occurred. + +Hahaha! + +You can't divide by zero, idiot! +\end{verbatim} + +The generated code: +\begin{verbatim} +try: + raise RuntimeError +except RuntimeError: + write('A runtime error occurred.\n') +write('\n') +try: + raise RuntimeError("Hahaha!") +except RuntimeError: + write(filter(VFN(sys,"exc_info",0)()[1])) + write('\n') +write('\n') +try: + write(filter(1/0)) + write('\n') +except ZeroDivisionError: + write("You can't divide by zero, idiot!\n") +\end{verbatim} + +\code{\#finally} works just like in Python. + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\subsection{\#assert} +\label{errorHandling.assert} + +The template: +\begin{verbatim} +#assert False, "You lose, buster!" +\end{verbatim} + +The output: +\begin{verbatim} +Traceback (most recent call last): + File "x.py", line 117, in ? + x().runAsMainProgram() + File "/local/opt/Python/lib/python2.2/site-packages/Webware/Cheetah/ +Template.py", line 331, in runAsMainProgram + CmdLineIface(templateObj=self).run() + File "/local/opt/Python/lib/python2.2/site-packages/Webware/Cheetah/ +TemplateCmdLineIface.py", line 59, in run + print self._template + File "x.py", line 91, in respond + assert False, "You lose, buster!" +AssertionError: You lose, buster! +\end{verbatim} + +The generated code: +\begin{verbatim} +assert False, "You lose, buster!" +\end{verbatim} + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\subsection{\#errorCatcher} +\label{errorHandling.errorCatcher} + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\subsubsection{No error catcher} +\label{errorHandling.errorCatcher.no} + +The template: +\begin{verbatim} +$noValue +\end{verbatim} + +The output: +\begin{verbatim} + +Traceback (most recent call last): + File "x.py", line 118, in ? + x().runAsMainProgram() + File "/local/opt/Python/lib/python2.2/site-packages/Webware/Cheetah/ +Template.py", line 331, in runAsMainProgram + CmdLineIface(templateObj=self).run() + File "/local/opt/Python/lib/python2.2/site-packages/Webware/Cheetah/ +TemplateCmdLineIface.py", line 59, in run + print self._template + File "x.py", line 91, in respond + write(filter(VFS(SL,"noValue",1))) # generated from '$noValue' at line +1, col 1. +NameMapper.NotFound: noValue +\end{verbatim} + +The generated code: +\begin{verbatim} +write(filter(VFS(SL,"noValue",1))) # generated from '$noValue' at line 1, + # col 1. +write('\n') +\end{verbatim} + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\subsubsection{Echo and BigEcho} +\label{errorHandling.errorCatcher.echo} + +The template: +\begin{verbatim} +#errorCatcher Echo +$noValue +#errorCatcher BigEcho +$noValue +\end{verbatim} + +The output: +\begin{verbatim} +$noValue +===============<$noValue could not be found>=============== +\end{verbatim} + +The generated code: +\begin{verbatim} +if self._errorCatchers.has_key("Echo"): + self._errorCatcher = self._errorCatchers["Echo"] +else: + self._errorCatcher = self._errorCatchers["Echo"] = ErrorCatchers.Echo(self) +write(filter(self.__errorCatcher1(localsDict=locals()))) + # generated from '$noValue' at line 2, col 1. +write('\n') +if self._errorCatchers.has_key("BigEcho"): + self._errorCatcher = self._errorCatchers["BigEcho"] +else: + self._errorCatcher = self._errorCatchers["BigEcho"] = \ + ErrorCatchers.BigEcho(self) +write(filter(self.__errorCatcher1(localsDict=locals()))) + # generated from '$noValue' at line 4, col 1. +write('\n') +\end{verbatim} + + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +\subsubsection{ListErrors} +\label{errorHandling.errorCatcher.listErrors} + +The template: +\begin{verbatim} +#import pprint +#errorCatcher ListErrors +$noValue +$anotherMissingValue.really +$pprint.pformat($errorCatcher.listErrors) +## This is really self.errorCatcher().listErrors() +\end{verbatim} + +The output: +\begin{verbatim} +$noValue +$anotherMissingValue.really +[{'code': 'VFS(SL,"noValue",1)', + 'exc_val': <NameMapper.NotFound instance at 0x8170ecc>, + 'lineCol': (3, 1), + 'rawCode': '$noValue', + 'time': 'Wed May 15 00:38:23 2002'}, + {'code': 'VFS(SL,"anotherMissingValue.really",1)', + 'exc_val': <NameMapper.NotFound instance at 0x816d0fc>, + 'lineCol': (4, 1), + 'rawCode': '$anotherMissingValue.really', + 'time': 'Wed May 15 00:38:23 2002'}] +\end{verbatim} + +The generated import: +\begin{verbatim} +import pprint +\end{verbatim} + +Then in the generated class, we have our familiar \code{.respond} method +and several new methods: +\begin{verbatim} +def __errorCatcher1(self, localsDict={}): + """ + Generated from $noValue at line, col (3, 1). + """ + + try: + return eval('''VFS(SL,"noValue",1)''', globals(), localsDict) + except self._errorCatcher.exceptions(), e: + return self._errorCatcher.warn(exc_val=e, code= 'VFS(SL,"noValue",1)' , + rawCode= '$noValue' , lineCol=(3, 1)) + +def __errorCatcher2(self, localsDict={}): + """ + Generated from $anotherMissingValue.really at line, col (4, 1). + """ + + try: + return eval('''VFS(SL,"anotherMissingValue.really",1)''', globals(), + localsDict) + except self._errorCatcher.exceptions(), e: + return self._errorCatcher.warn(exc_val=e, + code= 'VFS(SL,"anotherMissingValue.really",1)' , + rawCode= '$anotherMissingValue.really' , lineCol=(4, 1)) + +def __errorCatcher3(self, localsDict={}): + """ + Generated from $pprint.pformat($errorCatcher.listErrors) at line, col + (5, 1). + """ + + try: + return eval('''VFN(pprint,"pformat",0)(VFS(SL, + "errorCatcher.listErrors",1))''', globals(), localsDict) + except self._errorCatcher.exceptions(), e: + return self._errorCatcher.warn(exc_val=e, code= + 'VFN(pprint,"pformat",0)(VFS(SL,"errorCatcher.listErrors",1))' , + rawCode= '$pprint.pformat($errorCatcher.listErrors)' , + lineCol=(5, 1)) +\end{verbatim} +\begin{verbatim} +def respond(self, + trans=None, + dummyTrans=False, + VFS=valueFromSearchList, + VFN=valueForName, + getmtime=getmtime, + currentTime=time.time): + + + """ + This is the main method generated by Cheetah + """ + + if not trans: + trans = DummyTransaction() + dummyTrans = True + write = trans.response().write + SL = self._searchList + filter = self._currentFilter + globalSetVars = self._globalSetVars + + ######################################## + ## START - generated method body + + if exists(self._filePath) and getmtime(self._filePath) > self._fileMtime: + self.compile(file=self._filePath) + write(getattr(self, self._mainCheetahMethod_for_x)(trans=trans)) + if dummyTrans: + return trans.response().getvalue() + else: + return "" + if self._errorCatchers.has_key("ListErrors"): + self._errorCatcher = self._errorCatchers["ListErrors"] + else: + self._errorCatcher = self._errorCatchers["ListErrors"] = \ + ErrorCatchers.ListErrors(self) + write(filter(self.__errorCatcher1(localsDict=locals()))) + # generated from '$noValue' at line 3, col 1. + write('\n') + write(filter(self.__errorCatcher2(localsDict=locals()))) + # generated from '$anotherMissingValue.really' at line 4, col 1. + write('\n') + write(filter(self.__errorCatcher3(localsDict=locals()))) + # generated from '$pprint.pformat($errorCatcher.listErrors)' at line + # 5, col 1. + write('\n') + # This is really self.errorCatcher().listErrors() + + ######################################## + ## END - generated method body + + if dummyTrans: + return trans.response().getvalue() + else: + return "" +\end{verbatim} + +So whenever an error catcher is active, each placeholder gets wrapped in its +own method. No wonder error catchers slow down the system! + + +% Local Variables: +% TeX-master: "devel_guide" +% End: |