Das Ergebnis ist das gleiche unter Currying,
say map * **2 , 1, 3, 5, 7, 9;
(1 9 25 49 81)
say map *² , 1, 3, 5, 7, 9;
(1 9 25 49 81)
Auf der anderen Seite unterscheiden sich die Verhaltensweisen über den Cross-Meta-Operator.
say 1, 3, 5, 7, 9 X**2;
(1 9 25 49 81)
say 1, 3, 5, 7, 9 X²;
((1 2) (3 2) (5 2) (7 2) (9 2))
Warum verhalten sich ** 2 und ² bei Verwendung des Cross-Meta-Operators unterschiedlich?
Antworten:
Der XMetaoperator nimmt die beiden Listen, die er erhalten hat, und kombiniert sie mit dem von Ihnen angegebenen Operator. Wenn Sie ihm keinen Operator geben, wird er ,standardmäßig verwendet.
Also in diesem Fall:
say 1, 3, 5, 7, 9 X²
Der XMetaoperator sucht nach einem Infix-Operator. ²ist kein Infix-Operator, sondern ein Postfix.
So Xgilt ,als Betreiber. Aber jetzt ²wird es als Liste ausgewertet und in diesem Fall wird die Eigenschaft "Dies ist die Nummer 2" aktiviert.
Grundsätzlich sind diese gleich:
say 1, 3, 5, 7, 9 X²
say 1, 3, 5, 7, 9 X, 2
Wenn Sie alle Elemente in einer Liste quadrieren möchten, möchten Sie einen mapOperator verwenden. Wie am Anfang.
Inzwischen im IRC
<Doc_Holliwood> m: ².WHAT.say <camelia> rakudo-moar ed8f5141f: OUTPUT: «(Int)» <Doc_Holliwood> m: say 2 - ² <camelia> rakudo-moar ed8f5141f: OUTPUT: «0» * abraxxa has quit (Ping timeout: 252 seconds) <Doc_Holliwood> where is the magic? <Doc_Holliwood> m: 2².say <camelia> rakudo-moar ed8f5141f: OUTPUT: «4» <jnthn> I don't think there's any magic at all, it's just falling out of the standard parsing rules <AlexDaniel> u: ²⅓ <unicodable6> AlexDaniel, U+00B2 SUPERSCRIPT TWO [No] (²) <unicodable6> AlexDaniel, U+2153 VULGAR FRACTION ONE THIRD [No] (⅓) <Doc_Holliwood> somewhere something must be actively distinguishing <AlexDaniel> so any No has a numeric value <jnthn> Well, the parser knows when it's looking for a term and when it's looking for a postfix <AlexDaniel> you can use these unicode characters (that are No) as numeric literals <AlexDaniel> and yeah, what jnthn said :) <jnthn> It can't be looking for a postfix if it didn't yet see a term <AlexDaniel> we had a few tickets about this, people find it very surprising, but the parser doesn't <Doc_Holliwood> so ² is sometimes an int and sometimes its a postfix depending on context? <tobs> by the same rule, it can distinguish between multiplication and whatever star <AlexDaniel> well, similarly, yes <AlexDaniel> m: say (* * *)(2, 8) <camelia> rakudo-moar ed8f5141f: OUTPUT: «16» <jnthn> Doc_Holliwood: I guess, though only in the same sense that "+" in +$x is the numify operator, but in $a + $b it's the infix addition operator. <tobs> m: say 2²⁰ <camelia> rakudo-moar ed8f5141f: OUTPUT: «1048576» <jnthn> In general, the parser is always quite clear about what category of thing it would like to see next. <AlexDaniel> m: 2 2 <camelia> rakudo-moar ed8f5141f: OUTPUT: «===SORRY!=== Error while compiling <tmp>Two terms in a rowat <tmp>:1------> 2⏏ 2 expecting any of: infix infix stopper statement end statement modifier statement modifier…» <AlexDaniel> m: * 2 <camelia> rakudo-moar ed8f5141f: OUTPUT: «===SORRY!=== Error while compiling <tmp>Two terms in a rowat <tmp>:1------> *⏏ 2 expecting any of: infix infix stopper statement end statement modifier statement modifier …» <AlexDaniel> m: × 2 <camelia> rakudo-moar ed8f5141f: OUTPUT: «===SORRY!=== Error while compiling <tmp>Preceding context expects a term, but found infix × instead.at > <tmp>:1------> ×⏏ 2» <AlexDaniel> the error messages make it quite transparent :) <Doc_Holliwood> I'm just trying to wrap my head around the latest SO question. but it makes sense to me now. if ² ist a postfix, but X requires an infix. so X² cant DWTHAM <Doc_Holliwood> in order for say 1, 3, 5, 7, 9 X² to be 1 , 25, etc you would need to change how X works *** <jnthn> m: say (1, 3, 5, 7, 9)>>² *** <camelia> rakudo-moar ed8f5141f: OUTPUT: «(1 9 25 49 81)» <jnthn> Just use something that expects a postfix op :)