JavaScript-based formula interpreter-11 [function implementation]

FunctionBase function base class

File: FunctionBase. js

VaR $ functionmapper = []; </P> <p> // global function mapper <br/> function $ registerfunction (funcobj) {<br/> if ($ functionmapper [funcobj. get_functionname (). tolowercase ()]! = NULL) <br/> throw new exception (this, "$ registerfunction:" + funcobj. get_functionname () + "has registered"); </P> <p> $ functionmapper [funcobj. get_functionname (). tolowercase ()] = funcobj; <br/>}; </P> <p> function $ getregisterfunction (funcname) <br/>{< br/> if ($ functionmapper [funcname. tolowercase ()]! = NULL) <br/> return $ functionmapper [funcname. tolowercase ()]; <br/> else <br/> return NULL; <br/>}</P> <p> // --------------- functionbase -------------- <br/> function functionbase () {<br/> This. derivefrom (New operatorbase (); <br/> This. set_classname ("functionbase"); <br/> This. _ type = new functiontype ("undefined"); <br/>}; </P> <p> functionbase. prototype = {<br/> get_functionname: function () {return this. get_sign () ;}, <br/> evaluate: function (ARGs) {<br/> throw new exception (this, "not implemented "); <br/>}// evaluate <br/>}; // functionbase. prototype <br/>

 

Note that the implementation here is: there can be no function definition during Formula Parsing, while the global$ FunctionMapperTable for function name search. Corresponding,

The function must pass$ RegisterFunctionTo register.

Because you do not know the prior knowledge of a function, you need a definition to represent the function. This definition is the FunctionUnknown class.

 

FunctionUnknown class

File: FunctionBase. js

// ------------- FunctionUnknown ---------------- <br/> // Used for function parser <br/> function FunctionUnknown (arg) {<br/> this. deriveFrom (new FunctionBase (); <br/> this. set_ClassName ("FunctionUnknown"); </p> <p> if (arg! = Null) <br/> this. set_Sign (arg. toString (); <br/> else <br/> this. set_Sign ("undefined"); <br/>}; </p> <p> FunctionUnknown. prototype. evaluate = function (args) {<br/> var values = []; </p> <p> for (var I = 0; I <args. length; I ++) <br/> values. push (args [I]. get_Value (); </p> <p> $ Debug. writeLine ("Undefined function:" + this. get_Sign () + "(" + values. join (",") + "), assume return 0. "); <br/> return new OperandNumber (0); <br/>}; </p> <p> // Register operation shocould be completed MED after the prototype defined. <br/> $ RegisterFunction (new FunctionUnknown ());

 

Implementation of various functions

All Excel functions are not implemented here. There are only a few in the "frequently-used" directory. The PMT formula is unknown, so it is not implemented either. Leave it for homework:-P.

/// Function template <br/>/* <br/> function functionxxx () {<br/> This. derivefrom (New functionbase (); <br/> This. set_classname ("functionxxx"); <br/> This. set_sign ("XXX"); <br/>}; </P> <p> functionxxx. prototype. evaluate = function (ARGs) {</P> <p> // shocould return a value <br/> }; </P> <p> $ registerfunction (New functionxxx ()); <br/> */</P> <p> /////////////////////////// //// // <br/> // sum <br/> ////// /// // <Br/> function functionaverage () {<br/> This. derivefrom (New functionbase (); <br/> This. set_classname ("functionaverage"); <br/> This. set_sign ("average"); <br/>}; </P> <p> functionaverage. prototype = {<br/> evaluate: function (ARGs) {<br/> var res = 0; </P> <p> for (VAR I = 0; I <args. length; I ++) {<br/> If (! (ARGs [I]. isnumber () | ARGs [I]. isboolean () <br/> throw new exception (this, "evaluate", "unsupported argument:" + $ T (ARGs [I]); </P> <p> res + = ARGs [I]. get_value (); <br/>}</P> <p> return New operandnumber (RES/args. length); <br/>}< br/>}; </P> <p> $ registerfunction (New functionaverage ()); </P> <p> ///////////////////////////////// /// // <br/> // average <br/> /////////////////// /////////////////////// /<Br/> function functionsum () {<br/> This. derivefrom (New functionbase (); <br/> This. set_classname ("functionsum"); <br/> This. set_sign ("sum"); <br/>}; </P> <p> functionsum. prototype. evaluate = function (ARGs) {<br/> var res = 0; </P> <p> for (VAR I = 0; I <args. length; I ++) {<br/> If (! (ARGs [I]. isnumber () | ARGs [I]. isboolean () <br/> throw new exception (this, "evaluate", "unsupported argument:" + $ T (ARGs )); </P> <p> res + = ARGs [I]. get_value (); <br/>}</P> <p> return New operandnumber (RES); <br/> }; </P> <p> $ registerfunction (New functionsum ()); </P> <p> ///////////////////////////////// /// // <br/> // If <br/> /////////////////// /// // <br/> function functionif () {<br /> This. derivefrom (New functionbase (); <br/> This. set_classname ("functionif"); <br/> This. _ type = new functiontype ("if", 3); <br/>}; </P> <p> functionif. prototype. evaluate = function (ARGs) {<br/> If (! ARGs [0]. isboolean () <br/> throw new exception (this, "evaluate", "first argument shocould be boolean"); </P> <p> return ARGs [0]. get_value ()? ARGs [1]: ARGs [2]; <br/>}; </P> <p> $ registerfunction (New functionif ()); </P> <p> ///////////////////////////////// /// // <br/> // count <br/> /////////////////// /// // </P> <p> ///////// /// // <br/> // max <br/> /////////////////////////////////// /// // <br/> function functionmax () {<br/> This. derivefrom (New functionbase (); <br/> This. set_classname ("functionmax"); <br/> This. set_sign ("Max"); <br/>}; </P> <p> functionmax. prototype. evaluate = function (ARGs) {<br/> var res = 0; </P> <p> for (VAR I = 1; I <args. length; I ++) <br/> If (ARGs [I]. isnumber () <br/> If (RES <ARGs [I]. get_value () <br/> res = ARGs [I]. get_value (); </P> <p> return New operandnumber (RES); <br/>}; </P> <p> $ registerfunction (New functionmax ()); </P> <p> ///////////////////////////////// /// // <br/> // min <br/> /////////////////// /// // </P> <p> ///////// /// // <br/> // sin <br/> /////////////////////////////////// /// // <br/> function functionsin () {<br/> This. derivefrom (New functionbase (); <br/> This. set_classname ("functionsin"); <br/> This. _ type = new functiontype ("sin", 1); <br/>}; </P> <p> functionsin. prototype. evaluate = function (ARGs) {<br/> return New operandnumber (math. sin (ARGs [0]. get_value (); <br/>}; </P> <p> $ registerfunction (New functionsin ()); </P> <p> ///////////////////////////////// /// // <br/> // sumif <br/> /////////////////// /// // <br/> function functionsumif () {<br/> This. derivefrom (New functionbase (); <br/> This. set_classname ("functionsumif"); <br/> This. set_sign ("sumif"); <br/>}; </P> <p> functionsumif. prototype. evaluate = function (ARGs) {</P> <p> // depend on cell <br/> throw new exception (this, "evaluate", "not implemented "); <br/>}; </P> <p> $ registerfunction (New functionsumif ()); </P> <p> ///////////////////////////////// /// // <br/> // PMT <br/> /////////////////// /// // <br/> function functionpmt () {<br/> This. derivefrom (New functionbase (); <br/> This. set_classname ("functionpmt"); <br/> This. set_sign ("PMT"); <br/>}; </P> <p> functionpmt. prototype. evaluate = function (ARGs) {</P> <p> throw new exception (this, "evaluate", "not implemented"); <br/> }; </P> <p> $ registerfunction (New functionpmt ()); <br/> //////////////////////////////////// //// // <br/> // STDev <br/> ////////////////////// /// // <br/> function functionstdev () {<br/> This. derivefrom (New functionbase (); <br/> This. set_classname ("functionstdev"); <br/> This. set_sign ("STDev"); <br/>}; </P> <p> functionstdev. prototype. evaluate = function (ARGs) {<br/> var squaresum = 0, <br/> sum = 0; </P> <p> for (VAR I = 0; I <ARGs; I ++) {<br/> squaresum + = ARGs [I]. get_value () * ARGs [I]. get_value (); <br/> sum + = ARGs [I]. get_value (); <br/>}</P> <p> var res = math. SQRT (ARGs. length * squaresum-sum * sum)/(ARGs. length * (ARGs. length-1); </P> <p> return New operandnumber (RES); <br/> }; </P> <p> $ registerfunction (New functionstdev ());