Re: New experimental back end for C/C++ compiler targeting CLI

rockbrentwood@gmail.com schrieb:


> A really good source-to-source compiler should also be making proper
> adjustments to the comments. That may even entail a degree of natural language
> processing! Except for the "may" part.


Such problems occur only on source-to-source translation, where the
output should be human readable. A compilation into instructions of a
physical or virtual machine does not necessarily include comments, and
decompilation of executable code doesn't have to deal with comments at all.


Programming language translations are possible only for sufficiently
similar languages. If you look inside the "original VB" to MSIL
translation (not VB.NET), you'll find horrible constructs for the
implementation of the Basic ON ERROR... statements, even if both
languages are imperative.


In a source-to-source translation I'd not try to process comments,
except for structural parts like XML or doxygen tags.


In my C to Pascal converter I encountered many problems, not related to
control flow. I found most challenging the decisions, which parts of the
input should be "copied" unchanged, and which parts have to be
interpreted, i.e. must be broken down into more basic constructs. Even
if both language have equivalent control structures, like switch
statements, these may be semantically so different, that a direct
mapping is not always possible. The same for preprocessor statements -
can/should they be translated into equivalent high-level contstructs of
the target language, or do they have to be expanded before a translation?


DoDi

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