RakuAST: improve deparsing of nested ternaries

And add test for nested ternaries
rakudo · Jun 28, 2023 · dd55ffe · dd55ffe
1 parent 90ccaeb
commit dd55ffe
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Showing 2 changed files with 59 additions and 22 deletions.
diff --git a/src/core.c/RakuAST/Deparse.pm6 b/src/core.c/RakuAST/Deparse.pm6
@@ -2150,38 +2150,50 @@ class RakuAST::Deparse {
 
         # no place to store heredocs, make one, try again, add them at the end
         if nqp::istype($heredoc,Failure) {
+            my $*TERNARY = "";  # indenting for nested ternaries
+
             $heredoc := my $*HEREDOC := my str @;
             my $deparsed := self.deparse($ast);
 
-            nqp::elems($heredoc)
+            return nqp::elems($heredoc)
               ?? $deparsed ~ $heredoc.join ~ "\n"
               !! $deparsed
         }
 
         # already have a place to store heredocs
-        else {
-            my str @parts =
-              self.deparse($ast.condition),
-              self.hsyn('ternary', $.ternary1);
-
-            # helper sup for a ternary part
-            sub deparse-part($node --> Nil) {
-                if nqp::istype($node,RakuAST::Heredoc) {
-                    my str ($header,$rest) = self.deparse($node).split("\n",2);
-                    @parts.push($header);
-                    $heredoc.push("\n" ~ $rest.chomp);
-                }
-                else {
-                    @parts.push(self.deparse($node));
-                }
+        my $then := $ast.then;
+        my $else := $ast.else;
+        my $intern := $*TERNARY;
+        my $nested := $intern
+          || nqp::istype($then,RakuAST::Ternary)
+          || nqp::istype($else,RakuAST::Ternary);
+        my str $indent = $nested
+          ?? "\n" ~ ($intern ~= '  ').chop  # assume 1 space left of ?? !!
+          !! '';
+
+        my str @parts =
+          self.deparse($ast.condition),
+          $indent,
+          self.hsyn('ternary', $.ternary1);
+
+        # helper sub for a ternary part
+        sub deparse-part($node --> Nil) {
+            if nqp::istype($node,RakuAST::Heredoc) {
+                my str ($header,$rest) = self.deparse($node).split("\n",2);
+                @parts.push($header);
+                $heredoc.push("\n" ~ $rest.chomp);
             }
+            else {
+                @parts.push(self.deparse($node));
+            }
+        }
 
-            deparse-part($ast.then);
-            @parts.push(self.hsyn('ternary', $.ternary2));
-            deparse-part($ast.else);
+        deparse-part($then);
+        @parts.push($indent);
+        @parts.push(self.hsyn('ternary', $.ternary2));
+        deparse-part($else);
 
-            @parts.join
-        }
+        @parts.join
     }
 
 #- Trait -----------------------------------------------------------------------

diff --git a/t/12-rakuast/operators.rakutest b/t/12-rakuast/operators.rakutest
@@ -1,7 +1,7 @@
 use v6.e.PREVIEW;
 use Test;
 
-plan 31;
+plan 32;
 
 my $ast;
 my $deparsed;
@@ -461,6 +461,31 @@ subtest 'Correct outcome of ternary operator' => {
       for EVAL($ast), EVAL($deparsed), EVAL(EVAL $raku);
 }
 
+subtest 'Correct outcome of nested ternary operator' => {
+    # $a ?? $b ?? 22 !! 33 !! 44
+    ast RakuAST::Ternary.new(
+      condition => RakuAST::Var::Lexical.new("\$a"),
+      then      => RakuAST::Ternary.new(
+        condition => RakuAST::Var::Lexical.new("\$b"),
+        then      => RakuAST::IntLiteral.new(22),
+        else      => RakuAST::IntLiteral.new(33)
+      ),
+      else      => RakuAST::IntLiteral.new(44)
+    );
+    is-deeply $deparsed, q:to/CODE/.chomp, 'deparse';
+$a
+  ?? $b
+    ?? 22
+    !! 33
+  !! 44
+CODE
+
+    for 0,0,44, 1,0,33, 0,1,44, 1,2,22 -> $a, $b, $result {
+        is-deeply $_, $result, @type[$++]
+          for EVAL($ast), EVAL($deparsed), EVAL(EVAL $raku);
+    }
+}
+
 subtest 'Application of dotty infix `.`' => {
     # "foo" .uc()
     ast RakuAST::ApplyDottyInfix.new(