Hi,
I think you are having a detail problem are your description is a bit
too generic for that.
```groovy
import org.codehaus.groovy.macro.runtime.Macro
import org.codehaus.groovy.macro.runtime.MacroContext
import org.codehaus.groovy.ast.expr.Expression
import org.codehaus.groovy.ast.expr.MethodCallExpression
import org.codehaus.groovy.ast.expr.ArgumentListExpression
import org.codehaus.groovy.ast.stmt.BlockStatement
import static org.codehaus.groovy.macro.runtime.MacroGroovyMethods.macro
class GuardMacros {
@Macro
static Expression NOT_NULL(MacroContext ctx, MethodCallExpression
call) {
List<Expression> expressions = argList.getExpressions()
Expression finalExp = expressions.last()
List<Expression> checks = expressions.subList(0,
Expression resultAST = finalExp
for (int i = checks.size() - 1; i >= 0; i--) {
Expression currentCheck = checks[i]
resultAST = macro {
$v{currentCheck} != null ? $v{resultAST} : null
}
}
return resultAST
}
}
```
If you are using that kind of structure, then the possible problem is
that the ternary expression historically had some problems with using
the right type. But normally
On 9/23/26 22:45, MG wrote:
[...]
5. Question: How do I get the actual type of method parameters as given
in the source code (hope they have not been erased at this point,
since then I would be back to square one...) ?
1. e.g. (nonsensical, just to show the problem):
void foo(BigDecimal x0, BigDecimal x1) {
final BigDecimal x = NULL_TO(x0, x1) // still fails with
"cannot assign Object to BigDecimal", since the Expression#type
of the x0 and x1 Expression|s is a class node of type
java.lang.Object...
}
should then work. you can test it without the macro by actually writing
it as ternary expression in the source code. Just once. To verify.
6. Bonus question: What one evidently would want is not the type of one
of the Expression|s passed to NULL_TO, but instead the common
supertype of all the Expression|s - is there any accessible existing
functionality to get that ?-)
Eric already mentioned WideningCategories.lowestUpperBound. But I am not
sure if INFERRED_TYPE is available at the time the macro is executed.
If you really want to enforce the cast, I would consider a local
transform instead of a macro. Then you can work on the declaration
itself and use the left type to enforce a cast - maybe.
bye Jochen
