add hw2

node_modules/sucrase/dist/esm/parser/tokenizer/readWord.js

@@ -0,0 +1,64 @@
+import {input, state} from "../traverser/base";
+import {charCodes} from "../util/charcodes";
+import {IS_IDENTIFIER_CHAR} from "../util/identifier";
+import {finishToken} from "./index";
+import {READ_WORD_TREE} from "./readWordTree";
+import {TokenType as tt} from "./types";
+
+/**
+ * Read an identifier, producing either a name token or matching on one of the existing keywords.
+ * For performance, we pre-generate big decision tree that we traverse. Each node represents a
+ * prefix and has 27 values, where the first value is the token or contextual token, if any (-1 if
+ * not), and the other 26 values are the transitions to other nodes, or -1 to stop.
+ */
+export default function readWord() {
+  let treePos = 0;
+  let code = 0;
+  let pos = state.pos;
+  while (pos < input.length) {
+    code = input.charCodeAt(pos);
+    if (code < charCodes.lowercaseA || code > charCodes.lowercaseZ) {
+      break;
+    }
+    const next = READ_WORD_TREE[treePos + (code - charCodes.lowercaseA) + 1];
+    if (next === -1) {
+      break;
+    } else {
+      treePos = next;
+      pos++;
+    }
+  }
+
+  const keywordValue = READ_WORD_TREE[treePos];
+  if (keywordValue > -1 && !IS_IDENTIFIER_CHAR[code]) {
+    state.pos = pos;
+    if (keywordValue & 1) {
+      finishToken(keywordValue >>> 1);
+    } else {
+      finishToken(tt.name, keywordValue >>> 1);
+    }
+    return;
+  }
+
+  while (pos < input.length) {
+    const ch = input.charCodeAt(pos);
+    if (IS_IDENTIFIER_CHAR[ch]) {
+      pos++;
+    } else if (ch === charCodes.backslash) {
+      // \u
+      pos += 2;
+      if (input.charCodeAt(pos) === charCodes.leftCurlyBrace) {
+        while (pos < input.length && input.charCodeAt(pos) !== charCodes.rightCurlyBrace) {
+          pos++;
+        }
+        pos++;
+      }
+    } else if (ch === charCodes.atSign && input.charCodeAt(pos + 1) === charCodes.atSign) {
+      pos += 2;
+    } else {
+      break;
+    }
+  }
+  state.pos = pos;
+  finishToken(tt.name);
+}