This is how you create a anonymous function in PHP:
$newfunc = create_function('$a,$b', 'return "ln($a) + ln($b) = " . log($a * $b);');
Name:
Anonymous2007-08-30 16:13 ID:kjnv7mW9
lambda functions unusable in create_function()
I made five distinct tests to bracket the issue:
TEST 1:
// Creating a function that calls an ordinary function (explict name)
function always_true(){return true;}
$afun = create_function('', 'return !always_true();');
echo "Calling $afun() " . ($afun() ? "returns true\n" : "returns
false\n");
TEST 2:
// Creating a function that calls an ordinary function (variable name)
function always_true(){return true;}
$b1 = 'always_true';
$bfun = create_function('','return !'.$b1.'();');
echo "Calling $bfun() " . ($bfun() ? "returns true\n" : "returns
false\n");
TEST 3:
// Creating a function that calls an anonymous function (explicit
name);
$c1 = create_function('','return true;');
$cfun = create_function('','return !'.chr(0).'lambda_3();');
echo "Calling $cfun() " . ($cfun() ? "returns true\n" : "returns
false\n");
TEST 4:
// Creating a function that calls an anonymous function (variable name)
$d1 = create_function('','return true;');
$dfun = create_function('','return !'.$d1.'();');
echo "Calling $dfun() " . ($dfun() ? "returns true\n" : "returns
false\n");
TEST 5:
// Using is_callable to get a callable version of anonymous function
name
$e1 = create_function('', 'return true;');
if(!is_callable($e1,false,$callable_e1)) die("Couldn't call anonymous
function.");
echo "Using $callable_e1 as name of anonymous function\n";
$efun = create_function('','return !'.$callable_e1.'();');
echo "Calling $efun() " . ($efun() ? "returns true\n" : "returns
false\n");
Expected result:
----------------
TEST 1:
Calling lambda_1() returns false
TEST 2:
Calling lambda_1() returns false
TEST 3:
Calling lambda_2() returns false
TEST 4:
Calling lambda_2() returns false
TEST 5:
Using lambda_1 as name of anonymous function [?]
Calling lambda_2() returns false
Actual result:
--------------
Actual Results:
TEST 1:
Calling lambda_1() returns false
TEST 2:
Calling lambda_1() returns false
TEST 3:
Parse error: parse error, unexpected '}' in test.php : runtime-created
function on line 1
Fatal error: Function name must be a string in test.php on line 4
TEST 4:
Parse error: parse error, unexpected '}' in test.php : runtime-created
function on line 1
Fatal error: Function name must be a string in test.php on line 4
TEST 5:
Using as name of anonymous function
Parse error: parse error, unexpected ')' in test.php : runtime-created
function on line 1
Fatal error: Function name must be a string in test.php on line 6