lexer.js
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var Mexp=require('./math_function.js');
function inc(arr,val){
for(var i=0;i<arr.length;i++)
arr[i]+=val;
return arr;
}
var token=['sin','cos','tan','pi','(',')','P','C',
'asin','acos','atan','7','8','9','int',
'cosh','acosh','ln','^','root','4','5','6','/','!',
'tanh','atanh','Mod','1','2','3','*',
'sinh','asinh','e','log','0','.','+','-',',','Sigma','n','Pi','pow'];
var show=['sin','cos','tan','π','(',')','P','C',
'asin','acos','atan','7','8','9','Int',
'cosh','acosh',' ln','^','root','4','5','6','÷','!',
'tanh','atanh',' Mod ','1','2','3','×',
'sinh','asinh','e',' log','0','.','+','-',',','Σ','n','Π','pow'];
var eva=[Mexp.math.sin,Mexp.math.cos,Mexp.math.tan,'PI','(',')',Mexp.math.P,Mexp.math.C,
Mexp.math.asin,Mexp.math.acos,Mexp.math.atan,'7','8','9',Math.floor,
Mexp.math.cosh,Mexp.math.acosh,Math.log,Math.pow,Math.sqrt,'4','5','6',Mexp.math.div,Mexp.math.fact,
Mexp.math.tanh,Mexp.math.atanh,Mexp.math.mod,'1','2','3',Mexp.math.mul,
Mexp.math.sinh,Mexp.math.asinh,'E',Mexp.math.log,'0','.',Mexp.math.add,Mexp.math.sub,',',Mexp.math.sigma,'n',Mexp.math.Pi,Math.pow];
var preced={0:11,1:0,2:3,3:0,4:0,5:0,6:0,7:11,8:11,9:1,10:10,11:0,12:11,13:0};
var type=[0,0,0,3,4,5,10,10,
0,0,0,1,1,1,0,
0,0,0,10,0,1,1,1,2,7,
0,0,2,1,1,1,2,
0,0,3,0,1,6,9,9,11,12,13,12,8];
/*
0 : function with syntax function_name(Maths_exp)
1 : numbers
2 : binary operators like * / Mod left associate and same precedence
3 : Math constant values like e,pi,Cruncher ans
4 : opening bracket
5 : closing bracket
6 : decimal
7 : function with syntax (Math_exp)function_name
8: function with syntax function_name(Math_exp1,Math_exp2)
9 : binary operator like +,-
10: binary operator like P C or ^
11: ,
12: function with , seperated three parameters
13: variable of Sigma function
*/
var type0={0:true,1:true,3:true,4:true,6:true,8:true,9:true,12:true,13:true},//type2:true,type4:true,type9:true,type11:true,type21:true,type22
type1={0:true,1:true,2:true,3:true,4:true,5:true,6:true,7:true,8:true,9:true,10:true,11:true,12:true,13:true},//type3:true,type5:true,type7:true,type23
type_1={0:true,3:true,4:true,8:true,12:true,13:true},
empty={},
type_3={0:true,1:true,3:true,4:true,6:true,8:true,12:true,13:true},//type_5:true,type_7:true,type_23
type6={1:true},
newAr=[[],
["1","2","3","7","8","9","4","5","6","+","-","*","/","(",")","^","!","P","C","e","0",".",",","n"],
["pi","ln","Pi"],
["sin","cos","tan","Del","int","Mod","log","pow"],
["asin","acos","atan","cosh","root","tanh","sinh"],
["acosh","atanh","asinh","Sigma"]];
function match(str1,str2,i,x){
for(var f=0;f<x;f++){
if (str1[i+f]!==str2[f])
return false;
}
return true;
}
Mexp.addToken=function(tokens){
for(i=0;i<tokens.length;i++){
x=tokens[i].token.length;
var temp=-1;
//newAr is a specially designed data structure in which 1D array at location one of 2d array has all string with length 1 2 with 2 and so on
if (x<newAr.length) //match to check if token is really huge and not existing
//if not checked it will break in next line as undefined index
for(y=0;y<newAr[x].length;y++){
if (tokens[i].token===newAr[x][y]){
temp=token.indexOf(newAr[x][y]);
break;
}
}
if (temp===-1) {
token.push(tokens[i].token);
type.push(tokens[i].type);
if(newAr.length<=tokens[i].token.length)
newAr[tokens[i].token.length]=[];
newAr[tokens[i].token.length].push(tokens[i].token);
eva.push(tokens[i].value);
show.push(tokens[i].show);
}
else {
token[temp]=tokens[i].token;
type[temp]=tokens[i].type;
eva[temp]=tokens[i].value;
show[temp]=tokens[i].show;
}
}
};
Mexp.lex=function(inp,tokens){
'use strict';
var str=[{type:4,value:"(",show:"(",pre:0}];
var ptc=[]; //Parenthesis to close at the beginning is after one token
var inpStr=inp;
var key;
var pcounter=0;
var allowed=type0;
var bracToClose=0;
var asterick=empty;
var prevKey='';
var i,x,y;
if(typeof tokens!=="undefined")
Mexp.addToken(tokens);
var obj={};
for(i=0;i<inpStr.length;i++){
if (inpStr[i]==' ') {
continue;
}
key='';
sec:for(x=(inpStr.length-i>(newAr.length-2)?newAr.length-1:inpStr.length-i);x>0;x--){
for(y=0;y<newAr[x].length;y++){
if (match(inpStr,newAr[x][y],i,x)){
key=newAr[x][y];
break sec;
}
}
}
i+=key.length-1;
if(key===''){
throw(new Mexp.exception("Can't understand after "+inpStr.slice(i)));
}
var index=token.indexOf(key);
var cToken=key;
var cType=type[index];
var cEv=eva[index];
var cPre=preced[cType];
var cShow=show[index];
var pre=str[str.length-1];
for(j=ptc.length;j--;){ //loop over ptc
if(ptc[j]===0){
if([0,2,3,5,9,11,12,13].indexOf(cType)!==-1){
if(allowed[cType]!==true){
throw(new Mexp.exception(key+" is not allowed after "+prevKey));
}
str.push({value:")",type:5,pre:0,show:")"});
allowed=type1;
asterick=type_3;
inc(ptc,-1).pop();
}
}
}
if(allowed[cType]!==true){
throw(new Mexp.exception(key+" is not allowed after "+prevKey));
}
if(asterick[cType]===true){
cType=2;
cEv=Mexp.math.mul;
cShow="×";
cPre=3;
i=i-key.length;
}
obj={value:cEv,type:cType,pre:cPre,show:cShow};
if(cType===0){
allowed=type0;
asterick=empty;
inc(ptc,2).push(2);
str.push(obj);
str.push({value:"(",type:4,pre:0,show:"("});
}
else if(cType===1){
if(pre.type===1){
pre.value+=cEv;
inc(ptc,1);
}
else {
str.push(obj);
}
allowed=type1;
asterick=type_1;
}
else if(cType===2){
allowed=type0;
asterick=empty;
inc(ptc,2);
str.push(obj);
}
else if(cType===3){//constant
str.push(obj);
allowed=type1;
asterick=type_3;
}
else if(cType===4){
pcounter+=ptc.length;
ptc=[];
bracToClose++;
allowed=type0;
asterick=empty;
str.push(obj);
}
else if(cType===5){
if(!bracToClose){
throw(new Mexp.exception("Closing parenthesis are more than opening one, wait What!!!"));
}
while(pcounter--){ //loop over ptc
str.push({value:")",type:5,pre:0,show:")"});
}
pcounter=0;
bracToClose--;
allowed=type1;
asterick=type_3;
str.push(obj);
}
else if(cType===6){
if(pre.hasDec){
throw(new Mexp.exception("Two decimals are not allowed in one number"));
}
if(pre.type!==1){
pre={value:0,type:1,pre:0}; //pre needs to be changed as it will the last value now to be safe in later code
str.push(pre);
inc(ptc,-1);
}
allowed=type6;
inc(ptc,1);
asterick=empty;
pre.value+=cEv;
pre.hasDec=true;
}
else if(cType===7){
allowed=type1;
asterick=type_3;
inc(ptc,1);
str.push(obj);
}
if(cType===8){
allowed=type0;
asterick=empty;
inc(ptc,4).push(4);
str.push(obj);
str.push({value:"(",type:4,pre:0,show:"("});
}
else if(cType===9){
if(pre.type===9){
if(pre.value===Mexp.math.add){
pre.value=cEv;
pre.show=cShow;
inc(ptc,1);
}
else if(pre.value===Mexp.math.sub&&cShow==='-'){
pre.value=Mexp.math.add;
pre.show='+';
inc(ptc,1);
}
}
else if(pre.type!==5&&pre.type!==7&&pre.type!==1&&pre.type!==3&&pre.type!==13){//changesign only when negative is found
if(cToken==='-'){//do nothing for + token
//don't add with the above if statement as that will run the else statement of parent if on Ctoken +
allowed=type0;
asterick=empty;
inc(ptc,2).push(2);
str.push({value:Mexp.math.changeSign,type:0,pre:21,show:"-"});
str.push({value:"(",type:4,pre:0,show:"("});
}
}
else{
str.push(obj);
inc(ptc,2);
}
allowed=type0;
asterick=empty;
}
else if(cType===10){
allowed=type0;
asterick=empty;
inc(ptc,2);
str.push(obj);
}
else if(cType===11){
allowed=type0;
asterick=empty;
str.push(obj);
}
else if(cType===12){
allowed=type0;
asterick=empty;
inc(ptc,6).push(6);
str.push(obj);
str.push({value:"(",type:4,pre:0});
}
else if(cType===13){
allowed=type1;
asterick=type_3;
str.push(obj);
}
inc(ptc,-1);
prevKey=key;
}
for(var j=ptc.length;j--;){ //loop over ptc
if(ptc[j]===0){
str.push({value:")",show:")",type:5,pre:3});
inc(ptc,-1).pop();
}
}
if (allowed[5]!==true) {
throw(new Mexp.exception("complete the expression"));
}
while(bracToClose--)
str.push({value:")",show:")",type:5,pre:3});
str.push({type:5,value:")",show:")",pre:0});
// console.log(str);
return new Mexp(str);
};
module.exports=Mexp;