From 0182b5a10684632fc15fb714fabbc47c58977f45 Mon Sep 17 00:00:00 2001
From: akshan <akshan@gmail.com>
Date: Fri, 9 Oct 2020 12:15:02 +0530
Subject: [PATCH] first version

---
 .prettierrc    |  12 +++++
 WriteParser.js | 157 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 package.json   |  11 ++++
 3 files changed, 180 insertions(+)
 create mode 100644 .prettierrc
 create mode 100644 WriteParser.js
 create mode 100644 package.json

diff --git a/.prettierrc b/.prettierrc
new file mode 100644
index 0000000..d0bb80a
--- /dev/null
+++ b/.prettierrc
@@ -0,0 +1,12 @@
+{
+	"trailingComma": "all",
+	"useTabs": true,
+	"semi": true,
+	"singleQuote": false,
+	"quoteProps": "consistent",
+	"jsxSingleQuote": false,
+	"bracketSpacing": true,
+	"jsxBracketSameLine": true,
+	"arrowParens": "avoid",
+	"printWidth": 80
+}
diff --git a/WriteParser.js b/WriteParser.js
new file mode 100644
index 0000000..b4beea1
--- /dev/null
+++ b/WriteParser.js
@@ -0,0 +1,157 @@
+const { inspect } = require("util");
+
+function* prepare(str) {
+    for (let i = 0; i < str.length; i++) {
+        yield {
+            current: str[i],
+            next: (n = 1) => str.slice(i + 1, i + 1 + n),
+            prev: (n = 1) => str.slice(i - n, i),
+            skip: (n = 1) => (i += n),
+        };
+    }
+}
+
+function Parse(str, inner = false) {
+    let context = null;
+    let buffer = "";
+    let AST = [];
+    let link = "";
+
+    const flush = () => {
+        if (buffer) {
+            if (context === null && inner) {
+                AST.push(buffer);
+            } else {
+                if (context === "url") {
+                    AST.push({
+                        type: context,
+                        children: Parse(buffer, true),
+                        url: link,
+                    });
+                } else {
+                    AST.push({
+                        type: context || "text",
+                        children: context === null ? [buffer] : Parse(buffer, true),
+                    });
+                }
+            }
+            buffer = "";
+        }
+        context = null;
+        link = "";
+    };
+
+    for (const char of prepare(str)) {
+        const currentContext = context;
+        if (
+            (!context || context === "bold") &&
+            char.current === "*" &&
+            char.next() === "*"
+        ) {
+            flush();
+            if (!currentContext) {
+                context = "bold";
+            }
+            char.skip();
+        } else if (
+            (!context || context === "italics") &&
+            char.current === "_"
+        ) {
+            flush();
+            if (!currentContext) {
+                context = "italics";
+            }
+        } else if (
+            (!context || context === "strikethrough") &&
+            char.current === "~" &&
+            char.next() === "~"
+        ) {
+            flush();
+            if (!currentContext) {
+                context = "strikethrough";
+            }
+            char.skip();
+        } else if (
+            (!context || context === "underline") &&
+            char.current === "=" &&
+            char.next() === "="
+        ) {
+            flush();
+            if (!currentContext) {
+                context = "underline";
+            }
+            char.skip();
+        }
+        else if ((char.current === "[" || char.current === ']') && (!context || context === "link")) {
+            if (char.current === "[") {
+                flush();
+                context = "link";
+            }
+            if (inner) {
+                buffer += char.current;
+            }
+        }
+        else if ((context === "link" || !context || context === "url") && (char.current === "(" || char.current === ")") && !inner) {
+            if (char.prev() === "]") {
+                if (!currentContext || currentContext === "link") {
+                    context = "url";
+                }
+            }
+            else {
+                flush();
+            }
+        } else {
+            if (context === "url") {
+                link += char.current;
+            }
+            else {
+                buffer += char.current;
+            }
+        }
+    }
+
+    const updater = (char) => {
+        context = null;
+        let result = Parse(buffer);
+        for (const check of result) {
+            if (check.type !== "text") {
+                if (!AST.length) {
+                    buffer = char;
+                    flush();
+                }
+                AST.push(check);
+                buffer = "";
+            }
+            else {
+                buffer = check.children[0];
+                if (!AST.length) {
+                    buffer = char + buffer;
+                }
+                flush();
+            }
+        }
+    }
+
+    if (context === "bold") {
+        console.log("triggered");
+        updater("**");
+    } else if (context === "italics") {
+        updater("_");
+    } else if (context === "strikethrough") {
+        updater("~~");
+    } else if (context == "underline") {
+        updater("==");
+    }
+
+    if (buffer) {
+        context = null;
+        flush();
+    }
+
+    return AST;
+}
+
+const input = "[link](google.com)";
+
+console.log("input:", input);
+console.log("output:", inspect(Parse(input), false, Infinity, true));
diff --git a/package.json b/package.json
new file mode 100644
index 0000000..aa64e9f
--- /dev/null
+++ b/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "write-parser",
+  "version": "1.0.0",
+  "description": "",
+  "main": "WriteParser.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "author": "",
+  "license": "ISC"
+}