There is a precedent for such an operator (see https://en.wikipedia.org/wiki/Material_conditional <(https://en.wikipedia.org/wiki/Material_conditional> and https://en.wikipedia.org/wiki/Truth_table#Logical_implication) and I personally don't oppose it out of hand, despite it being slightly confusing for me having not dealt with/studied such an operator previously.
So working this out for my own benefit, and using the Venn diagram <https://en.wikipedia.org/wiki/Material_conditional#/media/File:Venn1011.svg> in the first Wikipedia link above to represent the condition being represented, red being the 'true' case and white being 'false', the example: if (itIsRaining => iAmUsingUmbrella) { println 'I am dry' } else { println 'I am wet' } could be written using more traditional operators as: if (!itIsRaining || iAmUsingUmbrella) { println 'I am dry' } else { println 'I am wet' } Using the truth table for implication (see 2nd link above): *Implication* *itIsRaining (p)**iAmUsingUmbrella (q)**p* → *q* T T T T F F F T T F F T and the wiki validates that *"p → q is equivalent to ¬p ∨ q." *So really, it is simply another way to represent a conditional relationship. I vote include it for those situations where this operator makes more sense. Those who don't need/like it can continue using more traditional operators. My $0.02. ;-) -Jeff On Fri, Jan 27, 2017 at 1:57 PM, Paolo Di Tommaso <paolo.ditomm...@gmail.com > wrote: > I agree on this. It could be very useful for custom DSL. > > > Cheers, Paolo > > On Fri, Jan 27, 2017 at 9:27 PM, Krzysztof Kowalczyk < > kowalczyk.krzysz...@gmail.com> wrote: > >> -1 >> >> but I would like to have some extra operators for AST transformation that >> are reserved, have priority and does not have assigned logic, for instance >> =>, |>, @@, ^^, <-, := etc >> >> On 27 January 2017 at 08:18, Graeme Rocher <graeme.roc...@gmail.com> >> wrote: >> >>> -1 from me, not immediately obvious what it does and seems like it >>> would just confuse users for little syntactic gain. >>> >>> On Thu, Jan 26, 2017 at 5:27 PM, Daniel Sun <realblue...@hotmail.com> >>> wrote: >>> > Hi all, >>> > >>> > The new parser(Parrot) supports "implies" operator(=>) now, e.g. >>> > >>> > // if and only if isDistributedTxFailed is true and isCompensated is >>> false, >>> > yields notConsistent. >>> > if (isDistributedTxFailed => isCompensated) { >>> > println 'eventuallyConsistent ' >>> > } else { >>> > println 'notConsistent' >>> > } >>> > >>> > // One more example: >>> > if (itIsRaining => iAmUsingUmbrella) { >>> > println 'I am dry' >>> > } else { >>> > println 'I am wet' >>> > } >>> > >>> > *More examples can be found at:* >>> > 1) >>> > https://github.com/danielsun1106/groovy-parser/blob/impliesO >>> perator/src/test/resources/core/ImpliesOp_01x.groovy >>> > 2) >>> > https://github.com/danielsun1106/groovy-parser/blob/impliesO >>> perator/src/test/resources/core/ImpliesOp_02x.groovy >>> > 3) >>> > https://github.com/danielsun1106/groovy-parser/blob/impliesO >>> perator/src/test/resources/core/ImpliesOp_03x.groovy >>> > >>> > *Background of the "implies" operator(=>) :* >>> > http://mathworld.wolfram.com/Implies.html >>> > *Please let us know whether you like it, vote here: >>> > *https://twitter.com/daniel_sun/status/824552059395465218 >>> > >>> > Cheers, >>> > Daniel.Sun >>> > >>> > >>> > >>> > -- >>> > View this message in context: http://groovy.329449.n5.nabble >>> .com/VOTE-About-the-implies-operator-for-Groovy-3-tp5738129.html >>> > Sent from the Groovy Users mailing list archive at Nabble.com. >>> >>> >>> >>> -- >>> Graeme Rocher >>> >> >> >
