/**
* @see http://www.scribd.com/doc/99533/Halstead-s-Operators-and-Operands-in-C-C-JAVA-by-Indranil-Nandy
*
* @param \PDepend\Source\AST\AbstractASTCallable $callable
* @return void
*/
public function calculateHalsteadBasis(AbstractASTCallable $callable)
{
$operators = array();
$operands = array();
$skipUntil = null;
$tokens = $callable->getTokens();
foreach ($tokens as $i => $token) {
/*
* Some operations should be ignored, e.g. function declarations.
* When we encounter a new function, we'll skip all tokens until we
* find the closing token.
*/
if ($skipUntil !== null) {
if ($token->type === $skipUntil) {
$skipUntil = null;
}
continue;
}
switch ($token->type) {
// A pair of parenthesis is considered a single operator.
case Tokens::T_PARENTHESIS_CLOSE:
case Tokens::T_CURLY_BRACE_CLOSE:
case Tokens::T_SQUARED_BRACKET_CLOSE:
case Tokens::T_ANGLE_BRACKET_CLOSE:
break;
// A label is considered an operator if it is used as the target
// of a GOTO statement.
// A label is considered an operator if it is used as the target
// of a GOTO statement.
case Tokens::T_GOTO:
$operators[] = $token->image;
// Ignore next token as operand but count as operator instead.
$skipUntil = $tokens[$i + 1]->type;
$operators[] = $tokens[$i + 1]->image;
break;
/*
* The following control structures case ...: for (...) if (...)
* switch (...) while(...) and try-catch (...) are treated in a
* special way. The colon and the parentheses are considered to
* be a part of the constructs. The case and the colon or the
* “for (...)”, “if (...)”, “switch (...)”, “while(...)”,
* “try-catch( )” are counted together as one operator.
*/
// case Tokens::T_SWITCH: // not followed by ()
// case Tokens::T_TRY: // not followed by ()
// case Tokens::T_DO: // always comes with while, which accounts for () already
/*
* The following control structures case ...: for (...) if (...)
* switch (...) while(...) and try-catch (...) are treated in a
* special way. The colon and the parentheses are considered to
* be a part of the constructs. The case and the colon or the
* “for (...)”, “if (...)”, “switch (...)”, “while(...)”,
* “try-catch( )” are counted together as one operator.
*/
// case Tokens::T_SWITCH: // not followed by ()
// case Tokens::T_TRY: // not followed by ()
// case Tokens::T_DO: // always comes with while, which accounts for () already
case Tokens::T_IF:
case Tokens::T_FOR:
case Tokens::T_FOREACH:
case Tokens::T_WHILE:
case Tokens::T_CATCH:
$operators[] = $token->image;
/*
* These are always followed by parenthesis, which would add
* another operator (only opening parenthesis counts)
* so we'll have to skip that one.
*/
$skipUntil = Tokens::T_PARENTHESIS_OPEN;
break;
/*
* The ternary operator ‘?’ followed by ‘:’ is considered a
* single operator as it is equivalent to “if-else” construct.
*/
/*
* The ternary operator ‘?’ followed by ‘:’ is considered a
* single operator as it is equivalent to “if-else” construct.
*/
case Tokens::T_COLON:
/*
* Colon is used after keyword, where it counts as part of
* that operator, or in ternary operator, where it also
* counts as 1.
*/
break;
// The comments are considered neither an operator nor an operand.
// The comments are considered neither an operator nor an operand.
case Tokens::T_DOC_COMMENT:
case Tokens::T_COMMENT:
break;
/*
* `new` is considered same as the function call, mainly because
* it's equivalent to the function call.
*/
/*
* `new` is considered same as the function call, mainly because
* it's equivalent to the function call.
*/
case Tokens::T_NEW:
break;
/*
* Like T_IF & co, array(..) needs 3 tokens ("array", "(" and
* ")") for what's essentially just 1 operator.
*/
/*
* Like T_IF & co, array(..) needs 3 tokens ("array", "(" and
* ")") for what's essentially just 1 operator.
*/
case Tokens::T_ARRAY:
break;
/*
* Class::method or $object->method both only count as 1
* identifier, even though they consist of 3 tokens.
*/
/*
* Class::method or $object->method both only count as 1
* identifier, even though they consist of 3 tokens.
*/
case Tokens::T_OBJECT_OPERATOR:
case Tokens::T_DOUBLE_COLON:
// Glue ->/:: and before & after parts together.
$image = array_pop($operands) . $token->image . $tokens[$i + 1]->image;
$operands[] = $image;
// Skip next part (would be seen as operand)
$skipUntil = $tokens[$i + 1]->type;
break;
// Ignore HEREDOC delimiters.
// Ignore HEREDOC delimiters.
case Tokens::T_START_HEREDOC:
case Tokens::T_END_HEREDOC:
break;
// Ignore PHP open & close tags and non-PHP content.
// Ignore PHP open & close tags and non-PHP content.
case Tokens::T_OPEN_TAG:
case Tokens::T_CLOSE_TAG:
case Tokens::T_NO_PHP:
break;
/*
* The function name is considered a single operator when it
* appears as calling a function, but when it appears in
* declarations or in function definitions it is not counted as
* operator.
* Default parameter assignments are not counted.
*/
/*
* The function name is considered a single operator when it
* appears as calling a function, but when it appears in
* declarations or in function definitions it is not counted as
* operator.
* Default parameter assignments are not counted.
*/
case Tokens::T_FUNCTION:
// Because `)` could appear in default argument assignment
// (`$var = array()`), we need to skip until `{`, but that
// one should be included in operators.
$skipUntil = Tokens::T_CURLY_BRACE_OPEN;
$operators[] = '{';
break;
/*
* When variables or constants appear in declaration they are
* not considered as operands, they are considered operands only
* when they appear with operators in expressions.
*/
/*
* When variables or constants appear in declaration they are
* not considered as operands, they are considered operands only
* when they appear with operators in expressions.
*/
case Tokens::T_VAR:
case Tokens::T_CONST:
$skipUntil = Tokens::T_SEMICOLON;
break;
case Tokens::T_STRING:
// `define` is T_STRING, just like any other identifier.
if ($token->image === 'define') {
// Undo all of "define", "(", name, ",", value, ")"
$skipUntil = Tokens::T_PARENTHESIS_CLOSE;
} else {
$operands[] = $token->image;
}
break;
// Operands
// Operands
case Tokens::T_CONSTANT_ENCAPSED_STRING:
case Tokens::T_VARIABLE:
case Tokens::T_LNUMBER:
case Tokens::T_DNUMBER:
case Tokens::T_NUM_STRING:
case Tokens::T_NULL:
case Tokens::T_TRUE:
case Tokens::T_FALSE:
case Tokens::T_CLASS_FQN:
case Tokens::T_LINE:
case Tokens::T_METHOD_C:
case Tokens::T_NS_C:
case Tokens::T_DIR:
case TOKENS::T_ENCAPSED_AND_WHITESPACE:
// content of HEREDOC
$operands[] = $token->image;
break;
// Everything else is an operator.
// Everything else is an operator.
default:
$operators[] = $token->image;
break;
}
}
$this->metrics[$callable->getId()] = array('n1' => count($operators), 'n2' => count($operands), 'N1' => count(array_unique($operators)), 'N2' => count(array_unique($operands)));
}
