RakuAST: add deparse/raku/test for RakuAST::MetaInfix::Zip

Also add a RakuAST::MetaInfix marker base class to allow typechecking
on any RakuAST::MetaInfix::xxx meta op (as ApplyListInfix deparsing
needs to be able to differentiate on that)

src/Raku/ast/expressions.rakumod

@@ -365,9 +365,13 @@ class RakuAST::Infix
     }
 }
 
+# Meta infixes base class, mostly for type checking
+class RakuAST::MetaInfix
+  is RakuAST::Infixish { }
+
 # An assign meta-operator, operator on another infix.
 class RakuAST::MetaInfix::Assign
-  is RakuAST::Infixish
+  is RakuAST::MetaInfix
 {
     has RakuAST::Infixish $.infix;
 
@@ -494,7 +498,7 @@ class RakuAST::FunctionInfix
 
 # A negate meta-operator.
 class RakuAST::MetaInfix::Negate
-  is RakuAST::Infixish
+  is RakuAST::MetaInfix
 {
     has RakuAST::Infixish $.infix;
 
@@ -530,7 +534,7 @@ class RakuAST::MetaInfix::Negate
 
 # A reverse meta-operator.
 class RakuAST::MetaInfix::Reverse
-  is RakuAST::Infixish
+  is RakuAST::MetaInfix
 {
     has RakuAST::Infixish $.infix;
 
@@ -557,7 +561,7 @@ class RakuAST::MetaInfix::Reverse
 
 # A cross meta-operator.
 class RakuAST::MetaInfix::Cross
-  is RakuAST::Infixish
+  is RakuAST::MetaInfix
 {
     has RakuAST::Infixish $.infix;
 
@@ -589,7 +593,7 @@ class RakuAST::MetaInfix::Cross
 
 # A zip meta-operator.
 class RakuAST::MetaInfix::Zip
-  is RakuAST::Infixish
+  is RakuAST::MetaInfix
 {
     has RakuAST::Infixish $.infix;
 
@@ -621,7 +625,7 @@ class RakuAST::MetaInfix::Zip
 
 # An infix hyper operator.
 class RakuAST::MetaInfix::Hyper
-  is RakuAST::Infixish
+  is RakuAST::MetaInfix
 {
     has RakuAST::Infixish $.infix;
     has Bool $.dwim-left;

src/core.c/RakuAST/Deparse.pm6

@@ -329,9 +329,12 @@ class RakuAST::Deparse {
     }
 
     multi method deparse(RakuAST::ApplyListInfix:D $ast --> Str:D) {
-        my str $operator = $ast.infix.operator;
-        my str @parts    = $ast.operands.map({ self.deparse($_) });
+        my $infix       := $ast.infix;
+        my str $operator = nqp::istype($infix,RakuAST::MetaInfix)
+          ?? (' ' ~ self.deparse($infix))
+          !! $infix.operator;
 
+        my str @parts = $ast.operands.map({ self.deparse($_) });
         @parts
           ?? $operator eq ','
             ?? @parts == 1
@@ -584,6 +587,10 @@ class RakuAST::Deparse {
         'R' ~ self.deparse($ast.infix)
     }
 
+    multi method deparse(RakuAST::MetaInfix::Zip:D $ast --> Str:D) {
+        'Z' ~ self.deparse($ast.infix)
+    }
+
     multi method deparse(RakuAST::Method:D $ast --> Str:D) {
         self!method($ast, 'method')
     }

src/core.c/RakuAST/Raku.pm6

@@ -379,6 +379,10 @@ augment class RakuAST::Node {
         self!positional(self.infix)
     }
 
+    multi method raku(RakuAST::MetaInfix::Zip:D: --> Str:D) {
+        self!positional(self.infix)
+    }
+
     multi method raku(RakuAST::Method:D: --> Str:D) {
         my str @nameds = 'name';
         @nameds.unshift("multiness") if self.multiness;

t/12-rakuast/meta-operators.rakutest

@@ -1,7 +1,7 @@
 use v6.e.PREVIEW;
 use Test;
 
-plan 6;
+plan 7;
 
 my $ast;
 my $deparsed;
@@ -49,6 +49,47 @@ subtest 'Reverse meta-op evaluates to expected value' => {
       for EVAL($ast), EVAL($deparsed), EVAL(EVAL $raku);
 }
 
+subtest 'Zip meta-op evaluates to expected value' => {
+    # (1, 2) Z== (1, 3)
+    ast RakuAST::ApplyListInfix.new(
+      infix    => RakuAST::MetaInfix::Zip.new(
+        RakuAST::Infix.new("==")
+      ),
+      operands => (
+        RakuAST::Circumfix::Parentheses.new(
+          RakuAST::SemiList.new(
+            RakuAST::Statement::Expression.new(
+              expression => RakuAST::ApplyListInfix.new(
+                infix    => RakuAST::Infix.new(","),
+                operands => (
+                  RakuAST::IntLiteral.new(1),
+                  RakuAST::IntLiteral.new(2),
+                )
+              )
+            )
+          )
+        ),
+        RakuAST::Circumfix::Parentheses.new(
+          RakuAST::SemiList.new(
+            RakuAST::Statement::Expression.new(
+              expression => RakuAST::ApplyListInfix.new(
+                infix    => RakuAST::Infix.new(","),
+                operands => (
+                  RakuAST::IntLiteral.new(1),
+                  RakuAST::IntLiteral.new(3),
+                )
+              )
+            )
+          )
+        ),
+      )
+    );
+
+    is-deeply $deparsed, '(1, 2) Z== (1, 3)', 'deparse';
+    is-deeply $_, (True, False), @type[$++]
+      for EVAL($ast), EVAL($deparsed), EVAL(EVAL $raku);
+}
+
 subtest 'Assignment meta-op with short-circuit || evaluates to true LHS' => {
     my $test = 10;
     my $update = 2;