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https://issues.apache.org/jira/browse/FREEMARKER-107?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16945429#comment-16945429
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Dániel Dékány commented on FREEMARKER-107:
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I have added an initial implementation of {{?spread_args}}, and initial version
of it at least. See:
*
[https://freemarker.apache.org/builds/fm2/ref_builtins_expert.html#ref_builtin_spread_args]
*
[https://repository.apache.org/content/repositories/snapshots/org/freemarker/freemarker/2.3.30-SNAPSHOT/]
*
[https://github.com/apache/freemarker/commit/54905b601b467692fd8f9c25618fd7e524d00acb]
Please try out if it's good for your use case this way.
One thing I will certainly change is the order of parameters. I think that
generally you want the parameters added by {{spread_args}} to appear at the end
of the parameter list, but currently they are added at the beginning of it. Or
maybe someone need both variation, and so there should be a
{{spread_args_first}} as well (and that's what the current implementation does).
> Hash expansion to macro arguments (Python **kwargs style)
> ---------------------------------------------------------
>
> Key: FREEMARKER-107
> URL: https://issues.apache.org/jira/browse/FREEMARKER-107
> Project: Apache Freemarker
> Issue Type: New Feature
> Components: engine
> Affects Versions: 2.3.28
> Reporter: Pascal Proulx
> Priority: Major
>
> Hello,
> We heavily rely on Freemarker macros to build a helper template API, but have
> had to make large workarounds for passing contents of hashes as macro
> arguments, for several years. (In truth I should have made this ticket much
> sooner!)
> It would help greatly simplify our work to have hash expansion to macro
> arguments, like this:
> {code:java}
> <#macro myMacro arg1 arg2 arg3="value3">...</#macro>
> <#assign myHash = {"arg1":"value1", "arg2":"value2"}>
> <@myMacro **myHash/><#-- the hash contents are passed as parameters, instead
> of the hash itself -->
> {code}
> This exists in Python:
> {code:java}
> def test_var_args_call(arg1, arg2, arg3):
> pass
> kwargs = {"arg3": 3, "arg2": "two"}
> test_var_args_call(1, **kwargs)
> {code}
> Essentially the hash contents fill in any arguments not explicitly specified.
> For the case where arguments are specified in addition to the hash, you may
> need to decide on a good syntax, e.g.:
> {code:java}
> <@myMacro arg1="value1" **myHash/>{code}
> This example doesn't have much precedent in freemarker syntax but is fairly
> understandable.
> Although we don't need it nearly as much, the same could be done with lists
> and function arguments:
> {code:java}
> <#function myFunc arg1 arg2>...</#function>
> <#assign myList = ["val1", "val2"]>
> ${myFunc(*myList)}
> <#assign myList = ["val2"]>
> ${myFunc("val1", *myList)}
> {code}
> Again similar to Python:
> {code:java}
> def test_var_args_call(arg1, arg2, arg3):
> pass
> args = ("two", 3)
> test_var_args_call(1, *args)
> {code}
> You might want this for consistency, although in practice the hash expansion
> will be many times more useful to us.
> If there's a lack a manpower I could try to see what I can do digging into
> the source, but wanted to bring this up for discussion first. It doesn't
> appear hard to implement to dump a hash into the macro args map, but there is
> defining the syntax.
> We use Freemarker 2.3.28 at the moment.
> Thank you
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