Add visitor system to Vocabulary\Symbol

Author: vojtech-dobes

src/GrammarProcessing/Vocabulary/Literal.php

@@ -37,4 +37,11 @@ public function acceptNode(
 		return new GrammarProcessing\TokenNode($token);
 	}
 
+
+
+	public function visit(callable $visitor): Symbol
+	{
+		return $visitor($this);
+	}
+
 }

src/GrammarProcessing/Vocabulary/NegativeLookahead.php

@@ -33,4 +33,11 @@ public function acceptNode(
 		return new GrammarProcessing\EmptyNode('NegativeLookahead');
 	}
 
+
+
+	public function visit(callable $visitor): Symbol
+	{
+		return $visitor($this);
+	}
+
 }

src/GrammarProcessing/Vocabulary/Nonterminal.php

@@ -32,4 +32,11 @@ public function acceptNode(
 			: new GrammarProcessing\TokenNode($tokenStream->consumeTokenWithType($this->nonterminal));
 	}
 
+
+
+	public function visit(callable $visitor): Symbol
+	{
+		return $visitor($this);
+	}
+
 }

src/GrammarProcessing/Vocabulary/OneOf.php

@@ -67,4 +67,21 @@ public function acceptNode(
 		return $result['node'];
 	}
 
+
+
+	public function visit(callable $visitor): Symbol
+	{
+		$result = [];
+
+		foreach ($this->symbols as $symbol) {
+			$result[] = $symbol->visit($visitor);
+		}
+
+		return $visitor(
+			$result === $this->symbols
+				? $this
+				: new self($result),
+		);
+	}
+
 }

src/GrammarProcessing/Vocabulary/Regexp.php

@@ -37,4 +37,11 @@ public function acceptNode(
 		);
 	}
 
+
+
+	public function visit(callable $visitor): Symbol
+	{
+		return $visitor($this);
+	}
+
 }

src/GrammarProcessing/Vocabulary/Repeat.php

@@ -69,4 +69,19 @@ public function acceptNode(
 		return new GrammarProcessing\ListNode($result);
 	}
 
+
+
+	public function visit(callable $visitor): Symbol
+	{
+		$visitedSymbol = $this->symbol->visit($visitor);
+
+		return $visitor(
+			$visitedSymbol === $this->symbol ? $this : new self(
+				$visitedSymbol,
+				$this->min,
+				$this->max,
+			),
+		);
+	}
+
 }

src/GrammarProcessing/Vocabulary/Sequence.php

@@ -42,4 +42,21 @@ public function acceptNode(
 		return new GrammarProcessing\ListNode($result);
 	}
 
+
+
+	public function visit(callable $visitor): Symbol
+	{
+		$visitedSymbols = [];
+
+		foreach ($this->symbols as $symbol) {
+			$visitedSymbols[] = $symbol->visit($visitor);
+		}
+
+		return $visitor(
+			$visitedSymbols === $this->symbols
+				? $this
+				: new self($visitedSymbols),
+		);
+	}
+
 }

src/GrammarProcessing/Vocabulary/Subtract.php

@@ -55,4 +55,21 @@ public function acceptNode(
 		return $node;
 	}
 
+
+
+	public function visit(callable $visitor): Symbol
+	{
+		$visitedBaseSymbol = $this->baseSymbol->visit($visitor);
+		$visitedSubtractedSymbol = $this->subtractedSymbol->visit($visitor);
+
+		$isDifferent = $visitedBaseSymbol !== $this->baseSymbol || $visitedSubtractedSymbol !== $this->subtractedSymbol;
+
+		return $visitor(
+			$isDifferent ? $this : new self(
+				$visitedBaseSymbol,
+				$visitedSubtractedSymbol,
+			),
+		);
+	}
+
 }

src/GrammarProcessing/Vocabulary/Symbol.php

@@ -24,4 +24,11 @@ function acceptNode(
 		array $nonterminals,
 	): GrammarProcessing\Node;
 
+
+
+	/**
+	 * @param callable(Symbol): Symbol $visitor
+	 */
+	function visit(callable $visitor): Symbol;
+
 }