Implement a configurable parser

src/V2/Exceptions/EmptyStreamException.php

@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Smoren\FormulaTools\V2\Exceptions;
+
+class EmptyStreamException extends UnexpectedEofException
+{
+    public function __construct()
+    {
+        parent::__construct('Cannot parse an empty stream', null);
+    }
+}

src/V2/Exceptions/MissingOperandException.php

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+<?php
+
+declare(strict_types=1);
+
+namespace Smoren\FormulaTools\V2\Exceptions;
+
+class MissingOperandException extends UnexpectedEofException
+{
+    public function __construct()
+    {
+        parent::__construct('Unexpected end of input; expecting a value', null);
+    }
+}

src/V2/Exceptions/MissingOperatorException.php

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+<?php
+
+declare(strict_types=1);
+
+namespace Smoren\FormulaTools\V2\Exceptions;
+
+class MissingOperatorException extends SyntaxException
+{
+    /**
+     * @readonly
+     * @var mixed
+     */
+    public $found;
+
+    /**
+     * @param mixed $token
+     * @param int $position
+     */
+    public function __construct($token, int $position)
+    {
+        parent::__construct("Expected an operator, found {$this->stringify($token)}", $position);
+        $this->found = $token;
+    }
+}

src/V2/Exceptions/OpAssociationException.php

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+<?php
+
+declare(strict_types=1);
+
+namespace Smoren\FormulaTools\V2\Exceptions;
+
+use Smoren\FormulaTools\V2\Interfaces\IOpDefinition;
+
+class OpAssociationException extends SyntaxException
+{
+    /** @readonly */
+    public IOpDefinition $op;
+
+    public function __construct(IOpDefinition $op, int $position)
+    {
+        parent::__construct('Operator `' . get_class($op) . '` is non-associative', $position);
+        $this->op = $op;
+    }
+}

src/V2/Exceptions/SyntaxException.php

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+<?php
+
+declare(strict_types=1);
+
+namespace Smoren\FormulaTools\V2\Exceptions;
+
+class SyntaxException extends \ErrorException
+{
+    /** @readonly */
+    public ?int $position;
+
+    public function __construct(string $msg, ?int $position)
+    {
+        $this->position = $position;
+        if ($position !== null) {
+            $position++;
+            $msg = "Token #$position: $msg";
+        }
+        parent::__construct($msg);
+    }
+
+    /**
+     * @param mixed $x
+     * @return string
+     */
+    protected function stringify($x): string
+    {
+        return json_encode(
+            $x,
+            JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE |
+            JSON_INVALID_UTF8_SUBSTITUTE | JSON_THROW_ON_ERROR,
+        );
+    }
+}

src/V2/Exceptions/UnclosedBracketException.php

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+<?php
+
+declare(strict_types=1);
+
+namespace Smoren\FormulaTools\V2\Exceptions;
+
+class UnclosedBracketException extends UnexpectedEofException
+{
+    public function __construct()
+    {
+        parent::__construct('Unexpected end of input; a bracket is not closed', null);
+    }
+}

src/V2/Exceptions/UnexpectedEofException.php

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+<?php
+
+declare(strict_types=1);
+
+namespace Smoren\FormulaTools\V2\Exceptions;
+
+class UnexpectedEofException extends SyntaxException
+{
+}