Andy Bierman <a...@yumaworks.com> wrote:
> Hi,
>
> The deviation section has a lot of fluff text about how bad deviations are,
> but very little text on how to process the "deviate" statement correctly.
>
> The text is not clear if the statements altered in the target module
> are semantic patches or syntactic patches. Are the sub-statements
> of the deviate-stmt fully processed in the scope of the deviation module
> or in the scope of the target module? In this example, is the type-stmt
> resolved in A or dev-A?
Deviations are not special compared to other statements; if you refer
to something in an external module the external module must be
imported and the prefixes are resolved in the module where they are
used. The type statement is resolved in the same way if it is defined
in a leaf, a typedef or in a deviate.
So in the examples below, all variants are legal.
> Similar issues for deviating a default for an identityref.
>
>
> module A {
> namespace "...";
> prefix a;
> // no imports!
>
> leaf foo {
> type string;
> }
>
> leaf bar {
> type string;
> }
>
> leaf baz {
> type string;
> }
> }
>
> module A-dev {
> ...
> import A { prefix a; }
> import C { prefix c; }
> import ietf-interfaces { prefix if; }
>
> // variant 1: inline leafref but module A does not import path module
> deviation /a:foo {
> deviate replace {
> type leafref {
> base /c:modules/c:module/c:name;
> }
> }
> }
>
>
> // variant 2: imported typedef but module A does not import it
> deviation /a:bar {
> deviate replace {
> type if:interface-ref;
> }
> }
>
>
> // variant 3: local typedef but module A cannot import it (circular
> imports)
> typedef mystring {
> type string { length "1..10"; }
> }
>
> deviation /a:baz {
> deviate replace {
> type mystring;
> }
> }
> }
/martin
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