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Added Stack class with support for rolling back changes.
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@SamMousa
SamMousa committed Apr 12, 2015
1 parent 695e3f4 commit fd4b02a
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Showing 5 changed files with 170 additions and 85 deletions.
194 changes: 111 additions & 83 deletions application/libraries/ExpressionManager/Parser.php
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Expand Up @@ -37,7 +37,7 @@ public function parse($string) {
// First tokenize it.
$this->tokenizer = new Tokenizer();
$tokens = $this->tokenizer->tokenize($string);
$stack = [];
$stack = new Stack();
while($this->parseExpression($tokens, $stack)) {}
$color = isset($this->error['token']) ? '#ff0000' : '#00ff00';
echo "<pre style='background-color: $color;'>";
Expand All @@ -55,7 +55,7 @@ public function parse($string) {
}
echo implode(' ', $parts) . "\n";
echo '</pre>';
return $stack;
return $stack->pop();
}


Expand All @@ -65,7 +65,8 @@ public function parse($string) {
* @param array $tokens
* @param array $stack
*/
protected function parseExpression(TokenStream $tokens, array &$stack) {
protected function parseExpression(TokenStream $tokens, Stack $stack) {
echo "Parsing {$tokens->getRest()}\n";
return $this->parseLogicExpression($tokens, $stack);
}

Expand All @@ -74,24 +75,24 @@ protected function parseExpression(TokenStream $tokens, array &$stack) {
* @param TokenStream $tokens
* @param array $stack
*/
protected function parseLogicExpression(TokenStream $tokens, array &$stack)
protected function parseLogicExpression(TokenStream $tokens, Stack $stack)
{
$result = $this->parseEqExpression($tokens, $stack);
if ($result) {
while ($result) {
$result = (
$tokens->begin()
$tokens->begin() && $stack->begin()
&& $this->parseToken('LOGIC_OP', $tokens, $stack)
&& $this->parseEqExpression($tokens, $stack)
&& $tokens->commit()
&& $tokens->commit() && $stack->commit()
)
|| $tokens->rollback();
|| $tokens->rollback() || $stack->rollback();
if ($result) {
// Combine.
$operand2 = array_pop($stack);
$operator = array_pop($stack);
$operand1 = array_pop($stack);
array_push($stack, [$operator, $operand1, $operand2]);
$operand2 = $stack->pop();
$operator = $stack->pop();
$operand1 = $stack->pop();
$stack->push([$operator, $operand1, $operand2]);
}
}
return true;
Expand All @@ -105,25 +106,25 @@ protected function parseLogicExpression(TokenStream $tokens, array &$stack)
* @param array $tokens
* @param array $stack
*/
protected function parseEqExpression(TokenStream $tokens, array &$stack) {
protected function parseEqExpression(TokenStream $tokens, Stack $stack) {
$result = $this->parseAddExpression($tokens, $stack);
if ($result) {
while ($result) {
$result = (
$tokens->begin()
$tokens->begin() && $stack->begin()
&& $this->parseToken('EQ_OP', $tokens, $stack)
&& (var_dump($tokens->getIndex()) || var_dump($tokens->getItems())|| true)
// && (var_dump($tokens->getIndex()) || var_dump($tokens->getItems())|| true)

&& $this->parseAddExpression($tokens, $stack)
&& $tokens->commit()
&& $tokens->commit() && $stack->commit()
)
|| $tokens->rollback();
|| $tokens->rollback() || $stack->rollback();
if ($result) {
// Combine.
$operand2 = array_pop($stack);
$operator = array_pop($stack);
$operand1 = array_pop($stack);
array_push($stack, [$operator, $operand1, $operand2]);
$operand2 = $stack->pop();
$operator = $stack->pop();
$operand1 = $stack->pop();
$stack->push([$operator, $operand1, $operand2]);
}
}
return true;
Expand All @@ -137,23 +138,23 @@ protected function parseEqExpression(TokenStream $tokens, array &$stack) {
* @param array $tokens
* @param array $stack
*/
protected function parseAddExpression(TokenStream $tokens, array &$stack) {
protected function parseAddExpression(TokenStream $tokens, Stack $stack) {
$result = $this->parseMultiExpression($tokens, $stack);
if ($result) {
while ($result) {
$result = (
$tokens->begin()
$tokens->begin() && $stack->begin()
&& $this->parseToken('ADD_OP', $tokens, $stack)
&& $this->parseMultiExpression($tokens, $stack)
&& $tokens->commit()
&& $tokens->commit() && $stack->commit()
)
|| $tokens->rollback();
|| $tokens->rollback() || $stack->rollback();
if ($result) {
// Combine.
$operand2 = array_pop($stack);
$operator = array_pop($stack);
$operand1 = array_pop($stack);
array_push($stack, [$operator, $operand1, $operand2]);
$operand2 = $stack->pop();
$operator = $stack->pop();
$operand1 = $stack->pop();
$stack->push([$operator, $operand1, $operand2]);
}
}
return true;
Expand All @@ -167,23 +168,23 @@ protected function parseAddExpression(TokenStream $tokens, array &$stack) {
* @param array $tokens
* @param array $stack
*/
protected function parseMultiExpression(TokenStream $tokens, array &$stack) {
protected function parseMultiExpression(TokenStream $tokens, Stack $stack) {
$result = $this->parsePrimary($tokens, $stack);
if ($result) {
while ($result) {
$result = (
$tokens->begin()
$tokens->begin() && $stack->begin()
&& $this->parseToken('MULTI_OP', $tokens, $stack)
&& $this->parsePrimary($tokens, $stack)
&& $tokens->commit()
&& $tokens->commit() && $stack->commit()
)
|| $tokens->rollback();
|| $tokens->rollback() || $stack->rollback();
if ($result) {
// Combine.
$operand2 = array_pop($stack);
$operator = array_pop($stack);
$operand1 = array_pop($stack);
array_push($stack, [$operator, $operand1, $operand2]);
$operand2 = $stack->pop();
$operator = $stack->pop();
$operand1 = $stack->pop();
$stack->push([$operator, $operand1, $operand2]);
}
}
return true;
Expand All @@ -198,46 +199,71 @@ protected function parseMultiExpression(TokenStream $tokens, array &$stack) {
* @param array $tokens
* @param array $stack
*/
protected function parsePrimary(TokenStream $tokens, array &$stack)
protected function parsePrimary(TokenStream $tokens, Stack $stack)
{
return (
$tokens->begin()
$tokens->begin() && $stack->begin()
&& $this->consumeToken('LP', $tokens, $stack)
&& $this->parseExpression($tokens, $stack)
&& $this->consumeToken('RP', $tokens, $stack)
&& $tokens->commit()
&& $tokens->commit() && $stack->commit()
)
|| $tokens->rollback()
|| $tokens->rollback() || $stack->rollback()
|| $this->parseValue($tokens, $stack)
|| (
$tokens->begin()
&& $this->parseToken('UN_OP', $tokens, $stack)
&& $this->parseExpression($tokens, $stack)
&& $tokens->commit()
)
|| $tokens->rollback()
|| $this->parseUnaryExpression($tokens, $stack)
|| $this->parseFunc($tokens, $stack)
|| $this->parseName($tokens, $stack);

|| $this->parseName($tokens, $stack)
|| $this->parseUnaryExpression($tokens, $stack, 'ADD_OP');
}

/**
* This parses an unary expression and puts the result on the stack.
* The type argument allows using it for + and - as well (they can be used as binary and unary ops).
* Rule: UN_OP EXPR
*
* @param TokenStream $tokens
* @param Stack $stack
*/
protected function parseUnaryExpression(TokenStream $tokens, Stack $stack, $type = 'UN_OP') {
if (($tokens->begin() && $stack->begin()
&& $this->parseToken($type, $tokens, $stack)
&& $this->parseExpression($tokens, $stack)
&& $tokens->commit() && $stack->commit()
)
|| $tokens->rollback() || $stack->rollback()) {
$operand = $stack->pop();
$operator = $stack->pop();
$stack->push([$operator, $operand]);
return true;
} else {
return false;
}
}

/**
* Rule: FUNC --> WORD LPAREN LIST RPAREN
* @param array $tokens
* @param array $stack
*/
protected function parseFunc(TokenStream $tokens, array &$stack)
protected function parseFunc(TokenStream $tokens, Stack $stack)
{
return (
$tokens->begin()
if ((
$tokens->begin() && $stack->begin()
&& $this->parseToken('WORD', $tokens, $stack, 'FUNC')
&& $this->consumeToken('LP', $tokens, $stack)
&& $this->parseList($tokens, $stack)
&& $this->consumeToken('RP', $tokens, $stack)
&& $tokens->commit()
&& $tokens->commit() && $stack->commit()
)
|| $tokens->rollback();
|| $tokens->rollback() || $stack->rollback()) {
$operands = $stack->pop();
$operator = $stack->pop();
$stack->push([$operator, $operands]);
return true;
} else {
return false;
}

}


Expand All @@ -246,33 +272,35 @@ protected function parseFunc(TokenStream $tokens, array &$stack)
* @param array $tokens
* @param array $stack
*/
protected function parseList(TokenStream $tokens, array &$stack) {
protected function parseList(TokenStream $tokens, Stack $stack) {
$result = $this->parseExpression($tokens, $stack);
if ($result) {
// List must be an array.
array_push($stack, [array_pop($stack)]);
$stack->push([$stack->pop()]);
while ($result) {
$result = (
$tokens->begin()
$tokens->begin() && $stack->begin()
&& $this->consumeToken('LISTSEPARATOR', $tokens, $stack)
&& $this->parseExpression($tokens, $stack)
&& $tokens->commit()
&& $tokens->commit() && $stack->commit()
)
|| $tokens->rollback();
|| $tokens->rollback() || $stack->rollback();
if ($result) {
// Combine.
$operand = array_pop($stack);
$operands = array_pop($stack);
$operand = $stack->pop();
$operands = $stack->pop();
// Push new operand onto operands.
array_push($operands, $operand);
// Push operands onto stack.
array_push($stack, $operands);
$stack->push($operands);
}
}
return true;
} else {
return false;
// List must be an array.
$stack->push([]);
}
// Always return true, empty list is valid.
return true;

}

Expand All @@ -285,23 +313,23 @@ protected function parseList(TokenStream $tokens, array &$stack) {
* @param null $context
* @return bool
*/
protected function parseToken($type, TokenStream $tokens, array &$stack, $context = null) {
protected function parseToken($type, TokenStream $tokens, Stack $stack, $context = null) {
while($this->consumeToken('WS', $tokens, $stack)) {}
if (!$tokens->end() && $tokens->peek()->type == $type) {

$token = $tokens->next();
if (isset($context)) {
$token->context = $context;
}
array_push($stack, $token);
$stack->push($token);
return true;
} else {
$this->error($type, $tokens, $stack);
return false;
}
}

protected function error($type, TokenStream $tokens, array &$stack) {
protected function error($type, TokenStream $tokens, Stack $stack) {
// Stores the last error.
if ($type != 'WS') {
$this->error = [
Expand All @@ -311,7 +339,7 @@ protected function error($type, TokenStream $tokens, array &$stack) {
];
}
}
protected function consumeToken($type, TokenStream $tokens, array &$stack) {
protected function consumeToken($type, TokenStream $tokens, Stack $stack) {
// Consume white space if any.
if ($type != 'WS') {
$this->consumeToken('WS', $tokens, $stack);
Expand All @@ -330,7 +358,7 @@ protected function consumeToken($type, TokenStream $tokens, array &$stack) {
* @param array $tokens
* @param array $stack
*/
protected function parseValue(TokenStream $tokens, array &$stack) {
protected function parseValue(TokenStream $tokens, Stack $stack) {
return $this->parseToken('STRING', $tokens, $stack, 'LITERAL')
|| $this->parseToken('BOOL', $tokens, $stack, 'LITERAL')
|| $this->parseToken('NUMBER', $tokens, $stack, 'LITERAL');
Expand All @@ -341,22 +369,22 @@ protected function parseValue(TokenStream $tokens, array &$stack) {
* @param array $tokens
* @param array $stack
*/
protected function parseName(TokenStream $tokens, array &$stack) {
protected function parseName(TokenStream $tokens, Stack $stack) {
// echo "<span style='background-color: blue;>Parsing name.</span>";
return (
$tokens->begin()
$tokens->begin() && $stack->begin()
&& $this->parseToken('SGQA', $tokens, $stack, 'VARIABLE')
&& $this->parseApply($tokens, $stack)
&& $tokens->commit()
&& $tokens->commit() && $stack->commit()
)
|| $tokens->rollback()
|| $tokens->rollback() || $stack->rollback()
|| (
$tokens->begin()
$tokens->begin() && $stack->begin()
&& $this->parseToken('WORD', $tokens, $stack, 'VARIABLE')
&& $this->parseApply($tokens, $stack)
&& $tokens->commit()
&& $tokens->commit() && $stack->commit()
)
|| $tokens->rollback();
|| $tokens->rollback() || $stack->rollback();

}

Expand All @@ -366,20 +394,20 @@ protected function parseName(TokenStream $tokens, array &$stack) {
* @param array $tokens
* @param array $stack
*/
protected function parseApply(TokenStream $tokens, array &$stack)
protected function parseApply(TokenStream $tokens, Stack $stack)
{
if ((
$tokens->begin()
$tokens->begin() && $stack->begin()
&& $this->consumeToken('APPLY', $tokens, $stack)
&& $this->parseToken('WORD', $tokens, $stack, 'FUNC')
&& $tokens->commit()
&& $tokens->commit() && $stack->commit()
)
|| $tokens->rollback()
|| $tokens->rollback() || $stack->rollback()
) {
// Basically this is a unary operator.
$operator = array_pop($stack);
$operand = array_pop($stack);
array_push($stack, [$operator, $operand]);
$operator = $stack->pop();
$operand = $stack->pop();
$stack->push([$operator, $operand]);

}
// Always return true since this is an optional rule.
Expand Down

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