1 files changed, 261 insertions, 0 deletions

diff --git a/Blog/Components/Pages/Concat.razor.js b/Blog/Components/Pages/Concat.razor.js
new file mode 100644
index 0000000..bd476e9
--- /dev/null
+++ b/Blog/Components/Pages/Concat.razor.js
@@ -0,0 +1,261 @@
+import { getById, div, span, h, writeError } from "/common.module.js";
+import lzString from "/lz-string.module.js";
+
+let definitions = {};
+let log = undefined;
+let input = undefined;
+
+export function onLoad() {
+    console.log('Loaded');
+    const form = getById("form");
+    input = getById("input");
+    log = getById("log");
+
+    form.onsubmit = async (event) => {
+        event.preventDefault();
+        await submitForm();
+    };
+
+    const urlParams = new URLSearchParams(window.location.search);
+    const queryInput = urlParams.get("in");
+
+    if (input.value.length === 0) {
+        input.value = lzString.decompressFromEncodedURIComponent(queryInput);
+    }
+}
+
+export function onUpdate() {
+    const urlParams = new URLSearchParams(window.location.search);
+    const queryInput = urlParams.get("in");
+
+    if (input.value.length === 0) {
+        input.value = lzString.decompressFromEncodedURIComponent(queryInput);
+    }
+}
+
+async function submitForm() {
+    console.log(input.value);
+    resetLog();
+    try {
+        definitions = {};
+        const stack = await evalString(input.value);
+        console.log(stack);
+
+        const path = window.location.pathname;
+        const params = new URLSearchParams(window.location.search);
+        const hash = window.location.hash;
+
+        params.set("in", lzString.compressToEncodedURIComponent(input.value));
+        window.history.replaceState(
+            {},
+            "",
+            `${path}?${params.toString()}${hash}`,
+        );
+    } catch (error) {
+        writeError(error);
+        console.log(error);
+    }
+}
+
+function splitWords(input) {
+    return input
+        .trim()
+        .split(/\s+/)
+        .filter((i) => i);
+}
+
+/** @param {string} inputString */
+function evalString(inputString) {
+    let words = splitWords(inputString);
+    return evalWords(words);
+}
+
+function effect2(f) {
+    return (stack) => {
+        if (stack.length <= 1) throw "stack underflow, need 2 numbers";
+        let [x, y, ...rest] = stack;
+        return [f(y, x), ...rest];
+    };
+}
+
+const plus = effect2((a, b) => a + b);
+const subtract = effect2((a, b) => a - b);
+const multiply = effect2((a, b) => a * b);
+const divide = effect2((a, b) => a / b);
+
+async function evalWords(inputWords) {
+    let words = inputWords;
+    let stack = [];
+
+    while (words.length > 0) {
+        await writeLog(stack, words);
+        if (words.length === 0) return stack;
+
+        let [word, ...rest] = words;
+        [stack, words] = evalWord(word, stack, rest);
+
+        await new Promise((r) => setTimeout(r, 100));
+    }
+    await writeLog(stack, words);
+    return stack;
+}
+
+function evalWord(word, stack, rest) {
+    switch (word) {
+        case "+":
+            return [plus(stack), rest];
+        case "-":
+            return [subtract(stack), rest];
+        case "*":
+            return [multiply(stack), rest];
+        case "/":
+            return [divide(stack), rest];
+        case "dup":
+            return [dup(stack), rest];
+        case "drop":
+            return [drop(stack), rest];
+        case "swap":
+            return [swap(stack), rest];
+        case "skip":
+            return skip(stack, rest);
+        case ",,":
+            return unquote(stack, rest);
+        case ":":
+            return [stack, define(rest)];
+        default:
+            return parse(word, stack, rest);
+    }
+}
+
+function unquote(stack, rest) {
+    let [quote, ...restStack] = stack;
+    if (typeof quote === "string" || quote instanceof String) {
+        return [restStack, [...splitWords(quote), ...rest]];
+    } else {
+        throw "not a string, only strings are unquoteable";
+    }
+}
+
+function skip(stack, words) {
+    if (stack.length === 0) throw "stack underflow, dont know how much to skip";
+    let [amount, ...restStack] = stack;
+
+    if (amount > words.length)
+        throw `program underflow, cant skip ${amount} words`;
+    if (amount <= 0) return [stack.slice(1), words]; // no skipping on <= 0
+
+    let restWords = words.slice(amount);
+
+    return [restStack, restWords];
+}
+
+function define(words) {
+    if (words.length < 2) throw "missing definition after ':'";
+    let [ident, ...rest] = words;
+    let index = 0;
+    let definition = [];
+
+    for (; index < rest.length; index++) {
+        const word = rest[index];
+        if (word === ";") {
+            break;
+        } else if (rest.length - 1 === index) {
+            throw "expected ';', found end of program";
+        }
+        definition.push(word);
+    }
+
+    definitions[ident] = definition;
+
+    return rest.slice(index + 1);
+}
+
+function dup(stack) {
+    if (stack.length === 0) throw "stack underflow, nothing to duplicate";
+    let [x, ...rest] = stack;
+    return [x, x, ...rest];
+}
+
+function drop(stack) {
+    if (stack.length === 0) throw "stack underflow, nothing to drop";
+    let [_, ...rest] = stack;
+    return rest;
+}
+
+function swap(stack) {
+    if (stack.length < 2) throw "stack underflow, not enough to swap";
+    let [x, y, ...rest] = stack;
+    return [y, x, ...rest];
+}
+
+function parse(word, stack, rest) {
+    if (word.startsWith('"')) {
+        return parseString(word, stack, rest);
+    }
+
+    if (word in definitions) {
+        return [stack, [...definitions[word], ...rest]];
+    }
+
+    let num = Number(word);
+    if (isNaN(num)) {
+        throw `word '${word}' not recognised`;
+    }
+
+    return [[num, ...stack], rest];
+}
+
+function parseString(word, stack, rest) {
+    if (word.length > 1 && word.endsWith('"')) {
+        return [[word.slice(1, -1), ...stack], rest];
+    }
+
+    let string = word.slice(1);
+    let index = 0;
+
+    for (; index < rest.length; index++) {
+        const word = rest[index];
+        if (word.endsWith('"')) {
+            string = string.concat(" ", word.slice(0, -1));
+            break;
+        } else if (rest.length - 1 === index) {
+            throw "expected word ending with '\"', found end of program";
+        }
+        string = string.concat(" ", word);
+    }
+
+    return [[string, ...stack], rest.slice(index + 1)];
+}
+
+function writeLog(stack, words) {
+    return new Promise((resolve, _reject) => {
+        let log_left = span(`[${stack.join(", ")}]`);
+        let log_right = span(words.join(" "));
+
+        if (words.length === 0) {
+            log_left.textContent += " <==";
+        }
+
+        let log_row = div(log_left, log_right);
+        log_row.className = "flex-spread";
+
+        log.appendChild(log_row);
+        resolve();
+    });
+}
+
+function resetLog() {
+    if (!log.hasChildNodes()) return;
+
+    let summary = h("summary");
+    summary.textContent = log.firstChild.lastChild.textContent;
+
+    let old_log = log.cloneNode(true);
+    old_log.id = "";
+
+    let details = h("details", summary, old_log);
+    details.className = "history";
+
+    log.insertAdjacentElement("afterend", details);
+    log.replaceChildren(); //remove children, clear log
+}