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PHP uses argc as a count of arguments and argv as an array containing the values of the arguments. [ 4 ] [ 5 ] To create an array from command-line arguments in the -foo:bar format, the following might be used:
Some people (including Guido van Rossum himself) have called this parameter-passing scheme "call by object reference". An object reference means a name, and the passed reference is an "alias", i.e. a copy of the reference to the same object, just as in C/C++. The object's value may be changed in the called function with the "alias", for example:
With named parameters, it is usually possible to provide the arguments in any order, since the parameter name attached to each argument identifies its purpose. This reduces the connascence between parts of the program. A few languages support named parameters but still require the arguments to be provided in a specific order.
An output parameter, also known as an out parameter or return parameter, is a parameter used for output, rather than the more usual use for input. Using call by reference parameters, or call by value parameters where the value is a reference, as output parameters is an idiom in some languages, notably C and C++, [ b ] while other languages have ...
One such example script was a CGI program called PHF that implemented a simple phone book. In common with a number of other scripts at the time, this script made use of a function: escape_shell_cmd(). The function was supposed to sanitize its argument, which came from user input and then pass the input to the Unix shell, to be run in the ...
For example, in Python the following is syntactically valid code: x = 1 print ( x ) The following code, however, is syntactically valid in terms of the context-free grammar, yielding a syntax tree with the same structure as the previous, but violates the semantic rule requiring variables to be initialized before use:
A chain of shebangs and wrappers yields a directly executable file that gets the encountered scripts as parameters in reverse order. For example, if file /bin/A is an executable file in ELF format, file /bin/B contains the shebang #!/bin/A optparam , and file /bin/C contains the shebang #!/bin/B , then executing file /bin/C resolves to /bin/B ...
In some languages, it is possible to create a nested function that accesses a set of parameters from the outer function, that is a closure, and have that function be the outer function's return value. Thus it is possible to return a function that is set to fulfill a certain task with little or no further parameters given to it, which can ...