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Custom Formatter - minimising impact when grammar changes? [message #799962]

Thu, 16 February 2012 14:07

Scott Finnie

Messages: 94
Registered: October 2011

Member

I have a simple custom formatter implemented for linewrap and indenting. For example,

c.setLinewrap().after( f.getClassAccess().getLeftCurlyBracketKeyword_3());

However: it's very sensitive to changes in the grammar. For example, if I add a new construct to the 'Class' rule, the method called above changes to:

getLeftCurlyBracketKeyword_4()

It's only the suffix that changes, but it breaks the formatter. Fixing it isn't difficult but is a bit of a nuisance. So I wondered if there's a way around it?

As a matter of interest, any reason why the _<x> suffix is there anyway? If it wasn't there this problem wouldn't occur...

thx.

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Re: Custom Formatter - minimising impact when grammar changes? [message #800022 is a reply to message #799962]

Thu, 16 February 2012 15:34

Sebastian Zarnekow

Messages: 3118
Registered: July 2009

Senior Member

Hi,

the suffix is used to make the names unique and to avoid silent breakage
of accesses. Consider the following example:

Rule:
'{' A '}’ | B '{' C '}'
;

Which one would be getLeftCurlyBracketKeyword() ?

You can workaround this issue by introducing own delegates thus every
suffixed method is only called by exactly one handwritten utility.

Regards,
Sebastian
--
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Am 16.02.12 15:07, schrieb sfinnie Mising name:
> I have a simple custom formatter implemented for linewrap and indenting.
> For example,
>
>
> c.setLinewrap().after( f.getClassAccess().getLeftCurlyBracketKeyword_3());
>
>
> However: it's very sensitive to changes in the grammar. For example, if
> I add a new construct to the 'Class' rule, the method called above
> changes to:
>
>
> getLeftCurlyBracketKeyword_4()
>
>
> It's only the suffix that changes, but it breaks the formatter. Fixing
> it isn't difficult but is a bit of a nuisance. So I wondered if there's
> a way around it?
>
> As a matter of interest, any reason why the _<x> suffix is there anyway?
> If it wasn't there this problem wouldn't occur...
>
> thx.

Report message to a moderator