User Function
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=== Features === | === Features === | ||
+ | |||
+ | === Embedding === | ||
+ | |||
+ | A class can be embedded inside an IF statement (or any statement) so that it can be created on a conditional for example: | ||
+ | |||
+ | <syntaxhighlight lang="sputnik"> | ||
+ | // Check if the function already exists and | ||
+ | // if it does already exists don't create it | ||
+ | if (!FunctionExists("Cat")) | ||
+ | { | ||
+ | // Create the function using the Embedded keyword | ||
+ | Embedded Function Cat() | ||
+ | { | ||
+ | say "testy!"; | ||
+ | }; // note ; is required here | ||
+ | } | ||
+ | Cat(); | ||
+ | // PRINTS | ||
+ | // testy! | ||
+ | </syntaxhighlight> | ||
=== Remarks === | === Remarks === | ||
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If you’ve most likely noticed that several function such as println() can take an indeterminate number of arguments. Normally when defining a function you specify each argument in the function declaration. Obviously it would be impossible to define an infinite number of arguments in such a way. Sputnik does, however, allow you to accomplish this through the array @args. | If you’ve most likely noticed that several function such as println() can take an indeterminate number of arguments. Normally when defining a function you specify each argument in the function declaration. Obviously it would be impossible to define an infinite number of arguments in such a way. Sputnik does, however, allow you to accomplish this through the array @args. | ||
− | @args is an array consisting of all of the arguments passed to a function. Using this method you can bypass the conventional method of defining parameters in the function definition all-together. Here is an example: | + | @args is an array consisting of all of the arguments passed to a function. Using this method you can bypass the conventional method of defining parameters in the function definition all-together. |
+ | |||
+ | However @args is not created by default and you must activate it if you wish to use it. | ||
+ | |||
+ | Here is an example: | ||
<syntaxhighlight lang="sputnik"> | <syntaxhighlight lang="sputnik"> | ||
println( Add(1, 2, 3) ); // will return 6 | println( Add(1, 2, 3) ); // will return 6 | ||
+ | // Allow the @args variable to be made (we will use it) | ||
+ | // you place this above a function to allow @Args | ||
+ | // the reason is becaus the creation of @Args involves | ||
+ | // creating an array and pushing items onto it etc and | ||
+ | // can use a tiny bit of processing power so we don't do | ||
+ | // it unless we want to do it | ||
+ | [Args("true")] | ||
Function Add() | Function Add() | ||
{ | { | ||
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doMsg("Hello", 777); | doMsg("Hello", 777); | ||
+ | [Args("true")] | ||
Function doMsg() | Function doMsg() | ||
{ | { | ||
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<pre> | <pre> | ||
TYPE WHAT IT DOES | TYPE WHAT IT DOES | ||
− | Args Allows | + | Args Allows enabling the creation of @ARGS variable |
Returns Forces a specific return type to the function | Returns Forces a specific return type to the function | ||
(gives exception if wrong type is given) | (gives exception if wrong type is given) | ||
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Override Overrides a CORE function with this name and forces all | Override Overrides a CORE function with this name and forces all | ||
call to that function to route to you function instead | call to that function to route to you function instead | ||
+ | </pre> | ||
+ | |||
+ | Default for the rules | ||
+ | <pre> | ||
+ | TYPE DEFAULT | ||
+ | Args FALSE | ||
+ | Returns <totally disabled> | ||
+ | ReturnCast <totally disabled> | ||
+ | Override FALSE | ||
</pre> | </pre> | ||
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<syntaxhighlight lang="sputnik"> | <syntaxhighlight lang="sputnik"> | ||
// The @Args variable is a special variable | // The @Args variable is a special variable | ||
− | // that | + | // that can be used in any function it is used to |
// handle infinite params the same as perls @_ | // handle infinite params the same as perls @_ | ||
− | // | + | // param 0 is @Args[0] and so on... |
− | // | + | // If you wish to use infinite parameters thenb |
− | + | // you must enable this rule. | |
− | + | ||
− | // | + | |
println("### First no rule"); | println("### First no rule"); | ||
Test("Cat", "Dog"); | Test("Cat", "Dog"); | ||
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TestWithRule("Cat", "Dog"); | TestWithRule("Cat", "Dog"); | ||
− | // A test function with no rules so @args should be created | + | // A test function with no rules so @args should NOT be created |
Function Test($a, $b) | Function Test($a, $b) | ||
{ | { | ||
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// This function is same as above but this time with the rule | // This function is same as above but this time with the rule | ||
− | [Args(" | + | [Args("true")] |
Function TestWithRule($a, $b) | Function TestWithRule($a, $b) | ||
{ | { | ||
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printr(@args); | printr(@args); | ||
} | } | ||
− | // Notice the test | + | // Notice the test without the rule had no @args variable at all? |
− | + | ||
− | + | ||
</syntaxhighlight> | </syntaxhighlight> | ||
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+ | In this example we dont include the ( ) on the function and by not including it the function will automatically assumes you plan to use the @args variable and will enable it for you | ||
<syntaxhighlight lang="sputnik"> | <syntaxhighlight lang="sputnik"> | ||
Test("CAT", 111); | Test("CAT", 111); | ||
− | |||
Function Test | Function Test | ||
{ | { | ||
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}; | }; | ||
</syntaxhighlight> | </syntaxhighlight> | ||
+ | |||
+ | [[Category:User Defined Functions]] |
Latest revision as of 10:08, 20 September 2015
Function <name> ( <Parameters> ... ) { statements ... }
Contents |
Description
Features
Embedding
A class can be embedded inside an IF statement (or any statement) so that it can be created on a conditional for example:
// Check if the function already exists and // if it does already exists don't create it if (!FunctionExists("Cat")) { // Create the function using the Embedded keyword Embedded Function Cat() { say "testy!"; }; // note ; is required here } Cat(); // PRINTS // testy!
Remarks
Examples
Important Examples
Parameters as pointers
You can pass variables as a pointer to a function so the function can modify them variables directly rather than work on a copy of them.
The only real benefit of doing this is it speeds up execution time by not having to copy the variable.
This is only useful when used on arrays especially very big arrays.
To make a pointer you use & like in C++ and place it in parameter section of the function.
// Make a string my $MyString = "Hello"; // Print it say $MyString; // Prints "Hello" // Fail to modify it Test($MyString); // Print to prove fail say $MyString; // Prints "Hello" // Correctly modify it Test2($MyString); // Print modified string say $MyString; // Prints "Hello world!" // A function that does not use a pointer // so any modifications to the variable // do not leave the function since it is // only playing with a *copy* Function Test($str) { $str .= " world!"; } // A function that does use a pointer so // any modifications that take place do // indeed change the variable Function Test2(&$str) { $str .= " world!"; }
Unlimited Function Parameters
If you’ve most likely noticed that several function such as println() can take an indeterminate number of arguments. Normally when defining a function you specify each argument in the function declaration. Obviously it would be impossible to define an infinite number of arguments in such a way. Sputnik does, however, allow you to accomplish this through the array @args.
@args is an array consisting of all of the arguments passed to a function. Using this method you can bypass the conventional method of defining parameters in the function definition all-together.
However @args is not created by default and you must activate it if you wish to use it.
Here is an example:
println( Add(1, 2, 3) ); // will return 6 // Allow the @args variable to be made (we will use it) // you place this above a function to allow @Args // the reason is becaus the creation of @Args involves // creating an array and pushing items onto it etc and // can use a tiny bit of processing power so we don't do // it unless we want to do it [Args("true")] Function Add() { my $Total = 0; foreach( @args as my $item ) { $Total += $item; } return $Total; }
If for whatever reason you need to know the total number of arguments passed to a function, You can simply use Count($args) within the function.
When retrieving arguments in this manner it is important to remember that @args only contains an array of arguments passed by the user. It does not account for default values etc.
Note - If outside a function @args will return an empty array.
Since @args exists it is possible to use that as the function parameters... Example
doMsg("Hello", 777); [Args("true")] Function doMsg() { my List( $msg, $code ) = @args; echo "$msg | $code"; // Prints: Hello | 777 } // This tends to work very similar to the @_ in perl
Function Rules
You can add special rules to your function to tell it how to operate using the [] brackets before the word "Function".
Here is a list of the possible rules:
TYPE WHAT IT DOES Args Allows enabling the creation of @ARGS variable Returns Forces a specific return type to the function (gives exception if wrong type is given) ReturnCast Casts all return values to this type if it is not already Override Overrides a CORE function with this name and forces all call to that function to route to you function instead
Default for the rules
TYPE DEFAULT Args FALSE Returns <totally disabled> ReturnCast <totally disabled> Override FALSE
For a list of data type to use with Returns/ReturnCast see HERE.
Example of using Rule: Args
// The @Args variable is a special variable // that can be used in any function it is used to // handle infinite params the same as perls @_ // param 0 is @Args[0] and so on... // If you wish to use infinite parameters thenb // you must enable this rule. println("### First no rule"); Test("Cat", "Dog"); println("### Now with rule"); TestWithRule("Cat", "Dog"); // A test function with no rules so @args should NOT be created Function Test($a, $b) { println("\$a: $a \$b: '$b'"); println("\@args[0]: @args[0] \@args[1]: '@args[1]'"); printr(@args); } // This function is same as above but this time with the rule [Args("true")] Function TestWithRule($a, $b) { println("\$a: $a \$b: '$b'"); println("\@args[0]: @args[0] \@args[1]: '@args[1]'"); printr(@args); } // Notice the test without the rule had no @args variable at all?
Example of using Rule: Returns
print(vardump(Test(true))); print(vardump(Test(false))); [Returns("bool")] Function Test( $returnBool ) { if($returnBool) return 1 == 2; else return "Hello"; } // This forces this function to require a bool to be returned // if a bool is not returned it will throw an exception instantly // it will not try to convert the return to a bool
Example of using Rule: ReturnCast
[ReturnCast("bool")] Function Test( $returnBool ) { if($returnBool) return 1 == 2; else return 1; } // This forces this function to return a bool no matter what // It will even return the default value (0 for ints, false for bool etc) // if it cannot convert or find a return value at all // If there is a return value it will converted to a bool
Example of using Rule: Override
Print("Moo moo farm"); [Override("true")] Function Print() { say "HELLO?!?!??"; } // This forces all calls to Print() (core) function to go to your // function instead this can prove useful if you are extending // the functionality of a core function. // Be careful however since Sputnik might want to call one of the // cores and suddenly find it does not exist and behave in weird and/or // disastrous way.
General Examples
println( Add(1, 2) ); // will return 3 Function Add($a, $b) { return $a + $b; }
println( Add(2) ); // will return 52 println( Add(2, 4) ); // will return 6 Function Add($a, $b = 50) { return $a + $b; }
println( Add() ); // will return 60 println( Add(2) ); // will return 52 println( Add(2, 4) ); // will return 6 Function Add($a = 10, $b = 50) { return $a + $b; }
In this example we dont include the ( ) on the function and by not including it the function will automatically assumes you plan to use the @args variable and will enable it for you
Test("CAT", 111); Function Test { my List ($Name, $Password) = @args; println("Name '$Name' Password '$Password'"); };