[jira] [Assigned] (GROOVY-8998) [GEP]Concatenative Method Calls

["Daniel Sun (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/GROOVY-8998?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Daniel Sun reassigned GROOVY-8998:
----------------------------------

    Assignee:     (was: Daniel Sun)

> [GEP]Concatenative Method Calls
> -------------------------------
>
>                 Key: GROOVY-8998
>                 URL: https://issues.apache.org/jira/browse/GROOVY-8998
>             Project: Groovy
>          Issue Type: New Feature
>            Reporter: Daniel Sun
>            Priority: Major
>
> h1.  *DRAFT*
> {code:java}
> // lots of temp variable declarations and assignments
> def ar = a()
> def br = b(3, ar)
> def  r = c(br, 2)
> // inline version of the above code, i.e. nested method calls
> def r =
> 	c(
> 		b(
> 			3,
> 			a()
> 		), 
> 		2
> 	)
> {code}
> {code:java}
> // leverage the power of DGM `with` to transform nested method calls to method call chain
> def r =
> 	a().with {
> 	   b(3, it)
> 	}. with {
> 	   c(it, 2)
> 	}
> {code}
> {code:java}
> //  Introduce a new syntax to transform the above method call chain to concatenative method calls
> //  `_`  represents the result of previous part
> //  `|>` is like a big arrow representing the direction of data flow
> // if the target is a variable, `|>` means assignment/declaration
> a()  |>  b(3, _)  |>  c(_, 2)  |> (def r)
> {code}
> h2. More examples
> {code:java}
> // `|>` has just a bit higher precedence than assignments, e.g. `=`, `+=`, `*=`, etc.
> 6 / a()  |>  b(3, _)  + 9 |>  c(_, 2) * 5  |> (def r)
> // the above code is equal to
> def r =
> 	c(
> 		b(
> 			3,
> 			6 / a()
> 		) + 9, 
> 		2
> 	) * 5
> {code}
> {code:java}
> // passing multiple parameters
> a(1), 6 / a(2)  |>  b(_, 3, _)  |> (def r)
> // the above code is equal to
> def r =
> 	b(
> 		a(1)
> 		3,
> 		6 / a(2)
> 	)
> {code}
> h2. discussion in the dev mailing list
>  [http://groovy.329449.n5.nabble.com/GEP-Concatenative-Method-Calls-tt5747708.html]



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