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https://issues.apache.org/jira/browse/GROOVY-10713?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17576767#comment-17576767
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Yih Tsern commented on GROOVY-10713:
------------------------------------
{quote}Afaik this transformer does also not visit inner classes.
{quote}
[~blackdrag] I don't think this will be a problem (at least for my project)
since the inner class will be treated just like any other top-level classes (my
global AST transformation class processes all classes).
{quote}Because ClassCodeExpressionTransformer is thought of more as "internal"
API.
{quote}
[~blackdrag] That may be your intention when you created that class, but [it
has since been documented as a public
API|https://github.com/apache/groovy/commit/9910b6d409d6eb946a7b86de37819d0ce63b3190].
😅
{quote}It does state "Transformed expressions are usually not visited." which
is maybe not that informative but does hint that transformation and (complete)
visitation are separate.
{quote}
[~emilles] I understand that javadoc to mean after an expression is
transformed, it won't be re-visited e.g. the code does NOT do something like
this:
{code:java}
public Expression transform(Expression exp) {
...
def transformedExp = exp.transformExpression(this);
transformedExp.visit(this); <-- I understand the Javadoc to mean it doesn't
do something like this
return transformedExp;
} {code}
Only [~blackdrag] can confirm whether I'm misunderstanding that, since [he was
the one who wrote the
javadoc|https://github.com/apache/groovy/commit/ef77a9384472b479eb8e6c67434fdf46f9a2708b#diff-ca42000c35d6b49b7738351b49858794f1d9287369731edd72e7331d9aed0b76].
h3. The wish
I was hoping for something like this in the javadoc and/or [the public
doc|https://groovy-lang.org/metaprogramming.html#_classcodeexpressiontransformer]:
{panel:title=💡 Expressions in ClosureExpression will not be visited, for
historical reason}
If you want to transform Expressions in ClosureExpressions, you need to do this:
{code:java}
class MyTransformer extends ClassCodeExpressionTransformer {
...
@Override
public Expression transform(Expression exp) {
// your customer instanceof checks and transformations
// ...
if (exp instanceof ClosureExpression) {
exp.visit(this);
return exp;
}
// ...
}
}
{code}
{panel}
To be honest, first-timers likely won't understand the significance of the note
above, but hopefully it will serve as a hint if and when a related bug is
logged for their implementation.
But I'm OK even if there's no such note, since the existence of this ticket (&
the replies) should be enough to serve as a guide.
> ClassCodeExpressionTransformer ignoring Expressions within
> ClosureExpression.code
> ---------------------------------------------------------------------------------
>
> Key: GROOVY-10713
> URL: https://issues.apache.org/jira/browse/GROOVY-10713
> Project: Groovy
> Issue Type: Bug
> Reporter: Yih Tsern
> Assignee: Eric Milles
> Priority: Minor
>
> E.g.
> {code:java}
> class SomeClass {
> def someClosureField = {
> // Expressions are NOT visited by
> ClassCodeExpressionTransformer.transform(Expression)
> }
>
> def someMethod() {
> // Expressions are visited by
> ClassCodeExpressionTransformer.transform(Expression)
> 3.times {
> // Expressions are NOT visited by
> ClassCodeExpressionTransformer.transform(Expression)
> }
> def someClosureVar = {
> // Expressions are NOT visited by
> ClassCodeExpressionTransformer.transform(Expression)
> }
> }
> }
> {code}
> Is this current behaviour by design or is it a bug? If it is by design, it
> seems to be quite a gotcha (also caused GROOVY-6932 & GROOVY-6434) - probably
> should be noted in [the
> doc|https://groovy-lang.org/metaprogramming.html#_classcodeexpressiontransformer]?
>
> Below is my current workaround(??) - is this the expected way to work with
> ClassCodeExpressionTransformer?
> {code:java}
> class MyAstTransformer extends ClassCodeExpressionTransformer {
> Expression transform(Expression expression) {
> // Some code to deal with specific expression classes...
> ...
>
> if (expression instanceof ClosureExpression) {
> expression.visit(this)
> }
> super.transform(expression);
> }
> }
> {code}
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