Difference between revisions of "Function"

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(Created page with "<c>function</c> is a keyword used to define a subprogram in MiniScript. The term "function" can also refer to such a subprogram. Category:Language...")
 
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<c>function</c> is a [[:Category:Keywords|keyword]] used to define a subprogram in MiniScript.  The term "function" can also refer to such a subprogram.
 
<c>function</c> is a [[:Category:Keywords|keyword]] used to define a subprogram in MiniScript.  The term "function" can also refer to such a subprogram.
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== Defining a Function ==
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A typical function definition looks something like this:
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<ms>identifier = function(param1, param2, param3)
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    // function body
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    return 42
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end function</ms>
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Parameters may have default values.  If not otherwise specified, the default value of a parameter is [[null]].  Default values must be literals (not expressions, variables, function calls, etc.).
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<ms>identifier = function(param1=1, param2="foo", param3)
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    // function body
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    return 42
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end function</ms>
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If the function takes no parameters, then the declaration would look like this:
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<ms>identifier = function
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    // function body
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    return 42
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end function</ms>
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Unlike some other languages, functions in MiniScript do not have names.  The <c>function... end function</c> structure returns a [[#Function_References|function reference]]; typically this is assigned to some variable, and then you can call the function via that variable.
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== Calling a Function ==
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Any time an identifier (with or without dot syntax) that contains a function reference is evaluated, the function is automatically invoked.  [[Parentheses]] are needed around any arguments to the function if the call is part of a larger expression (rather than a command statement).  If no arguments are to be passed to the function, then no parentheses are ever needed.
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The following are all valid function calls.
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<ms>someFunc
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someFunc arg1, arg2
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x = someFunc
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y = someFunc(arg1, arg2)</ms>
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== Function References ==
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Sometimes you want to get a function reference ''without'' actually invoking the function.  This can be done in two ways:
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# Use the <c>@</c> operator before the function identifier.  This (often read "address of") operator blocks the usual function invocation.  Example: <c>f = @someFunc</c>
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# Fetch the value out of a map using square-brackets indexing rather than dot syntax.  Example: <c>f = locals["someFunc"]</c>
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A function reference has the type [[FuncRef|funcRef]].
  
 
[[Category:Language]]
 
[[Category:Language]]
 
[[Category:Keywords]]
 
[[Category:Keywords]]
 
{{stub}}
 

Latest revision as of 15:36, 27 April 2023

function is a keyword used to define a subprogram in MiniScript. The term "function" can also refer to such a subprogram.

Defining a Function

A typical function definition looks something like this:

identifier = function(param1, param2, param3)
    // function body
    return 42
end function

Parameters may have default values. If not otherwise specified, the default value of a parameter is null. Default values must be literals (not expressions, variables, function calls, etc.).

identifier = function(param1=1, param2="foo", param3)
    // function body
    return 42
end function

If the function takes no parameters, then the declaration would look like this:

identifier = function
    // function body
    return 42
end function

Unlike some other languages, functions in MiniScript do not have names. The function... end function structure returns a function reference; typically this is assigned to some variable, and then you can call the function via that variable.

Calling a Function

Any time an identifier (with or without dot syntax) that contains a function reference is evaluated, the function is automatically invoked. Parentheses are needed around any arguments to the function if the call is part of a larger expression (rather than a command statement). If no arguments are to be passed to the function, then no parentheses are ever needed.

The following are all valid function calls.

someFunc
someFunc arg1, arg2
x = someFunc
y = someFunc(arg1, arg2)

Function References

Sometimes you want to get a function reference without actually invoking the function. This can be done in two ways:

  1. Use the @ operator before the function identifier. This (often read "address of") operator blocks the usual function invocation. Example: f = @someFunc
  2. Fetch the value out of a map using square-brackets indexing rather than dot syntax. Example: f = locals["someFunc"]

A function reference has the type funcRef.