[cfe-dev] LibFormat usage question

[David Blaikie]

On Thu, Oct 31, 2013 at 6:32 AM, Jesper Eskilson <Jesper.Eskilson at iar.com>wrote:

>
> Hi,
>
> I'm trying to figure out how to programmatically invoke clang-format to
> format code. I would like to get from a declaration ("Decl *") to a plain
> string containing the reformatted source code.
>

It's generally advised that one should not attempt to round trip source
code through the AST. Use the AST to inform mutations of the original
source (by using source locations to identify pieces to move, insert, or
remove), rather than to produce new source from the parsed AST.


>
> Here's my feeble initial attempt:
>
>
> /*
>  * Non-functioning attempt att trying to extract the source code of
>  * 'decl' formatted using LLVM style.
>  */
> std::string get_formatted_source(SourceManager &mgr, const Decl *decl)
> {
>   StringRef code = get_source(mgr, decl); // implemented elsewhere
>   std::vector<Range> ranges;
>   LangOptions lo;
>   Rewriter rw(mgr, lo);
>
>   Range range(0, src.size());
>   ranges.push_back(range);
>
>   // Do the reformat
>   auto repl = reformat(getLLVMStyle(), code, ranges);
>
>   // Apply the replacements
>   for (auto it = repl.begin(); it != repl.end(); ++it) {
>     it->apply(rw);
>   }
>
>   // Extract the reformatted source code.
>   auto formatted_source = rw.getRewrittenText(decl->getSourceRange());
>
>   // I would have expected 'formatted_source' to be the formatted source
>   // here, but it is always the same as the original, as if the
>   // replacements where never applied.
> }
>
>
> --
> *Jesper Eskilson* *Development Engineer*
> IAR Systems AB
> Box 23051, Strandbodgatan 1
> SE-750 23 Uppsala, SWEDEN
> E-mail: jesper.eskilson at iar.com Website: www.iar.com
>  Twitter: www.twitter.com/iarsystems
>
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>
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