https://none-none1.github.io/Interpret-Esolangs-Online/arithmetic.js

1// A slight modification of a JavaScript interpreter (https://esolangs.org/wiki/Talk:Arithmetic) by the esolang user PythonshellDebugwindow, which is put in the public domain.
2function arithmetic(program,input)
3{
4    const lines = program.split("\n");
5    let output = "";
6    let state = 0, currentExam = 0;
7    let currentProblem, currentChoice, pointsEarned;
8    let correctAnswer, problemPoints, answerDict;
9    let m; //Holds the result of RegExp matches
10    let currentLineNumber = 0;
11    
12    for(const line of lines)
13    {
14        ++currentLineNumber;
15        //Skip empty lines
16        if(line === "")
17        {
18            continue;
19        }
20        //State 0 (begin exam)
21        else if(state === 0)
22        {
23            if(line === `==Begin Exam ${currentExam + 1}==`)
24            {
25                ++currentExam;
26                state = 1;
27                currentProblem = 1;
28                pointsEarned = 0;
29                continue;
30            }
31        }
32        //State 1 (begin problem, end exam)
33        else if(state === 1)
34        {

35            //Match a problem declaration, e.g. 1. 2+3=? (100 points)
36            if((m = line.match(/^([0-9]+). ([0-9]+)\+([0-9]+)=\? \(([0-9]+) points\)$/)))
37            {
38                //Must be positive integers
39                if((+m[2]) > 0 && (+m[3]) > 0)
40                {
41                    //Check if the problem number is correct
42                    if((+m[1]) === currentProblem)
43                    {
44                        ++currentProblem;
45                        answerDict = {};
46                        currentChoice = 0;
47                        correctAnswer = (+m[2]) + (+m[3]);
48                        problemPoints = m[4];
49                        ++state;
50                        continue;
51                    }
52                }
53            }
54            else if(line === `==End Exam ${currentExam}==`)
55            {
56                state = 0;
57                output += String.fromCharCode(pointsEarned % 256);
58                continue;
59            }
60        }
61        //State 2 (problem choices)
62        else if(state === 2)
63        {

64            //Match the current choice letter (A, B, etc.) followed by a period, space, then number
65            if(m = line.match(new RegExp("^(" + String.fromCharCode(currentChoice + 65) + ")\. ([0-9]+)$")))
66            {
67                //Problems can have up to 26 choices
68                if(currentChoice < 26)
69                {
70                    ++currentChoice;
71                    //Must be a positive integer
72                    if(+m[2] > 0)
73                    {
74                        //Check for duplicate correct answers
75                        if(!(Object.values(answerDict).indexOf(m[2]) > -1 && (+m[2]) === correctAnswer))
76                        {
77                            answerDict[m[1]] = m[2];
78                            continue;
79                        }
80                    }
81                }
82            }
83            else if((m = line.match(/^Answer: ([A-Z])$/)))
84            {
85                //Check whether the chosen answer is a valid choice
86                if(m[1].charCodeAt(0) - 65 < currentChoice)
87                {
88                    //Check whether the chosen answer is correct
89                    if((+answerDict[m[1]]) === correctAnswer)
90                    {
91                        pointsEarned += (problemPoints % 256);
92                    }
93                    --state;
94                    continue;
95                }
96            }
97        }
98        throw new Error("Invalid syntax on line " + currentLineNumber);
99    }
100    if(state !== 0)
101    {
102        //The last line was not the end of an exam
103        throw new Error("Unexpected end of input");
104    }
105    return output;
106}