functioncall

#functionCall

##Syntax A functionCall is:

functionId [ ( [ expn { , expn } ] ) ]

##Description A function call is an expression that calls (invokes or activates) a function. If the function has parameters, a parenthesized list of expressions (expns) must follow the function's name (functionId).

##Example This function takes a string containing a blank and returns the first word in the string (all the characters up to the first blank).

    function firstWord ( str : string ): string
        for i : 1 .. length ( str )
            if str ( i ) = " " then
                result str ( 1 .. i - 1)
            end if
        end for
    end firstWord
    
    put "The first word is: ", firstWord ("Henry Hudson")   
                    % The output is Henry.

##Details The parameter declared in the header of a function, is a formal parameter, for example, str above is a formal parameter. Each expression in the call is an actual parameter, for example, sample above is an actual parameter.

Each actual parameter passed to its non-var formal parameter must be assignable to that parameter (see assignability for details). See also functionDeclaration and procedureDeclaration.

In this explanation of functionCall, we have up to this point ignored the possibility of functions exported from modules. If the function is being called from outside of a module from which it has been exported, the syntax of the functionCall is:

In other words, the module or monitor name and a dot must precede the function's name. If the function is being called from outside of a class from which it has been exported, the syntax of the functionCall is one of:

In these p must be a pointer value that locates an object in the class. Form (b) is a short form for form (a).

    moduleId . functionId [ ( expn {, expn } ) ]        (a) classId ( p ) . functionId [ ( [ expn {, expn } ] ) ]
    (b) p -> functionId [ ( [ expn {, expn } ] ) ]

##See also class.html.