---
title: osmarkscalculator
description: Unholy horrors moved from the depths of my projects directory to your browser. Theoretically, this is a calculator. Good luck using it.
---
<textarea id="program" style="width: 100%; resize: vertical" rows="5"></textarea>
<pre id="output"></pre>
<button id="go">Go</button>
<button id="clear">Clear Context</button>
<select id="examples">
</select>
<script>
    const examples = {
        "blank": "",
        "factorial": `Fac[n] = Fac[n-1]*n
Fac[0] = 1
Fac[17]
`,
        "expand": "(a+b)*(c+d)*(e+f)*(g+h)",
        "expand2": "(a+b)^3*(b+c)-d",
        "fibonacci": `Fib[n] = Fib[n-1] + Fib[n-2] 
Fib[0] = 0 
Fib[1] = 1 
Fib[6]
`,
        "predicate": `IsEven[x] = 0
IsEven[x#Eq[Mod[x, 2], 0]] = 1
IsEven[3] - IsEven[4]`,
        "derivative": `D[3*x^3 + 6*x, x]`,
        "simplify": `x^a/x^(a+1)`,
        "simplify2": "Negate[a+b] + b",
        "arith": `(12+55)^3-75+16/(2*2)+5+3*4`,
        "subst": "Subst[x=4, x+4+4+4+4]"
    }
    const examplesSelector = document.querySelector("#examples")
    const program = document.querySelector("#program")
    for (const name of Object.keys(examples)) {
        const opt = document.createElement("option")
        opt.value = name
        opt.appendChild(document.createTextNode(name))
        examplesSelector.appendChild(opt)
    }
    examplesSelector.addEventListener("change", () => {
        program.value = examples[examplesSelector.value]
    })
    var worker = new Worker("osmarkscalculator.js")
    const forceKill = () => {
        console.warn("Force-terminating worker.")
        worker.terminate()
        worker = new Worker("osmarkscalculator.js")
    }
    const write = data => {
        const out = document.querySelector("#output")
        while (out.firstChild) { out.removeChild(out.firstChild) }
        out.appendChild(document.createTextNode(data))
    }
    document.querySelector("#go").addEventListener("click", () => {
        console.log(program.value)
        write("Running...")
        worker.postMessage(["run", program.value])
        var timeout = setTimeout(() => {
            forceKill()
            write("Execution timeout")
        }, 5000)
        worker.onmessage = ev => {
            const [status, result, time] = ev.data
            if (status === "ok") {
                write(result + `\nin ${time}ms`)
            } else {
                write("Internal error: " + result + `\nin ${time}ms`)
            }
            clearInterval(timeout)
        }
    })
    document.querySelector("#clear").addEventListener("click", () => worker.postMessage(["deinit"]))
</script>