Merge pull request #31 from phpcr/cnd-parser

CND parser

Author: dbu

src/PHPCR/Util/CND/Exception/ParserException.php

@@ -0,0 +1,31 @@
+<?php
+
+namespace PHPCR\Util\CND\Exception;
+
+use PHPCR\Util\CND\Scanner\TokenQueue,
+    PHPCR\Util\CND\Scanner\GenericToken;
+
+/**
+ * @author Daniel Barsotti <daniel.barsotti@liip.ch>
+ */
+class ParserException extends \Exception
+{
+    public function __construct(TokenQueue $queue, $msg)
+    {
+        $token = $queue->peek();
+        $msg = sprintf("PARSER ERROR: %s. Current token is [%s, '%s'] at line %s, column %s", $msg, GenericToken::getTypeName($token->getType()), $token->getData(), $token->getLine(), $token->getRow());
+
+        // construct a lookup of the next tokens
+        $lookup = '';
+        for($i = 1; $i <= 5; $i++) {
+            if ($queue->isEof()) {
+                break;
+            }
+            $token = $queue->get();
+            $lookup .= $token->getData() . ' ';
+        }
+        $msg .= "\nBuffer lookup: \"$lookup\"";
+
+        parent::__construct($msg);
+    }
+}

src/PHPCR/Util/CND/Exception/ScannerException.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace PHPCR\Util\CND\Exception;
+
+use PHPCR\Util\CND\Reader\ReaderInterface;
+
+/**
+ * @author Daniel Barsotti <daniel.barsotti@liip.ch>
+ */
+class ScannerException extends \Exception
+{
+    public function __construct(ReaderInterface $reader, $msg)
+    {
+        $msg = sprintf(
+            "SCANNER ERROR: %s at line %s, column %s.\nCurrent buffer \"%s\"",
+            $msg,
+            $reader->getCurrentLine(),
+            $reader->getCurrentColumn(),
+            $reader->consume()
+        );
+
+        parent::__construct($msg);
+    }
+}

src/PHPCR/Util/CND/Parser/AbstractParser.php

@@ -0,0 +1,118 @@
+<?php
+
+namespace PHPCR\Util\CND\Parser;
+
+use PHPCR\Util\CND\Scanner\GenericToken as Token;
+use PHPCR\Util\CND\Scanner\TokenQueue;
+use PHPCR\Util\CND\Exception\ParserException;
+
+/**
+ * Abstract base class for parsers
+ *
+ * It implements helper functions for parsers:
+ *
+ *      - checkToken            - check if the next token matches
+ *      - expectToken           - expect the next token to match
+ *      - checkAndExpectToken   - check and then expect the next token to match
+ *
+ * @author Daniel Barsotti <daniel.barsotti@liip.ch>
+ */
+abstract class AbstractParser
+{
+    /**
+     * The token queue
+     * @var TokenQueue
+     */
+    protected $tokenQueue;
+
+    /**
+     * Check the next token without consuming it and return true if it matches the given type and data.
+     * If the data is not provided (equal to null) then only the token type is checked.
+     * Return false otherwise.
+     *
+     * @param int $type The expected token type
+     * @param null|string $data The expected data or null
+     *
+     * @return bool
+     */
+    protected function checkToken($type, $data = null)
+    {
+        if ($this->tokenQueue->isEof()) {
+            return false;
+        }
+
+        $token = $this->tokenQueue->peek();
+
+        if ($token->getType() !== $type) {
+            return false;
+        }
+
+        if ($data && $token->getData() !== $data) {
+            return false;
+        }
+
+        return true;
+    }
+
+    /**
+     * Check if the token data is one of the elements of the data array.
+     *
+     * @param int   $type
+     * @param array $data
+     *
+     * @return bool
+     */
+    protected function checkTokenIn($type, array $data)
+    {
+        foreach ($data as $d) {
+            if ($this->checkToken($type, $d)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Check if the next token matches the expected type and data. If it does, then consume and return it,
+     * otherwise throw an exception.
+     *
+     * @param int $type The expected token type
+     * @param null|string $data The expected token data or null
+     *
+     * @return Token
+     *
+     * @throws ParserException
+     */
+    protected function expectToken($type, $data = null)
+    {
+        $token = $this->tokenQueue->peek();
+
+        if (!$this->checkToken($type, $data)) {
+            throw new ParserException($this->tokenQueue, sprintf("Expected token [%s, '%s']", Token::getTypeName($type), $data));
+        }
+
+        $this->tokenQueue->next();
+
+        return $token;
+    }
+
+    /**
+     * Check if the next token matches the expected type and data. If it does, then consume it, otherwise
+     * return false.
+     *
+     * @param int $type The expected token type
+     * @param null|string $data The expected token data or null
+     * @return bool|Token
+     */
+    protected function checkAndExpectToken($type, $data = null)
+    {
+        if ($this->checkToken($type, $data)) {
+            $token = $this->tokenQueue->peek();
+            $this->tokenQueue->next();
+            return $token;
+        }
+
+        return false;
+    }
+}