add hw2

node_modules/sucrase/dist/esm/parser/traverser/lval.js

@@ -0,0 +1,159 @@
+import {flowParseAssignableListItemTypes} from "../plugins/flow";
+import {tsParseAssignableListItemTypes, tsParseModifiers} from "../plugins/typescript";
+import {
+  eat,
+  IdentifierRole,
+  match,
+  next,
+  popTypeContext,
+  pushTypeContext,
+} from "../tokenizer/index";
+import {ContextualKeyword} from "../tokenizer/keywords";
+import {TokenType, TokenType as tt} from "../tokenizer/types";
+import {isFlowEnabled, isTypeScriptEnabled, state} from "./base";
+import {parseIdentifier, parseMaybeAssign, parseObj} from "./expression";
+import {expect, unexpected} from "./util";
+
+export function parseSpread() {
+  next();
+  parseMaybeAssign(false);
+}
+
+export function parseRest(isBlockScope) {
+  next();
+  parseBindingAtom(isBlockScope);
+}
+
+export function parseBindingIdentifier(isBlockScope) {
+  parseIdentifier();
+  markPriorBindingIdentifier(isBlockScope);
+}
+
+export function parseImportedIdentifier() {
+  parseIdentifier();
+  state.tokens[state.tokens.length - 1].identifierRole = IdentifierRole.ImportDeclaration;
+}
+
+export function markPriorBindingIdentifier(isBlockScope) {
+  let identifierRole;
+  if (state.scopeDepth === 0) {
+    identifierRole = IdentifierRole.TopLevelDeclaration;
+  } else if (isBlockScope) {
+    identifierRole = IdentifierRole.BlockScopedDeclaration;
+  } else {
+    identifierRole = IdentifierRole.FunctionScopedDeclaration;
+  }
+  state.tokens[state.tokens.length - 1].identifierRole = identifierRole;
+}
+
+// Parses lvalue (assignable) atom.
+export function parseBindingAtom(isBlockScope) {
+  switch (state.type) {
+    case tt._this: {
+      // In TypeScript, "this" may be the name of a parameter, so allow it.
+      const oldIsType = pushTypeContext(0);
+      next();
+      popTypeContext(oldIsType);
+      return;
+    }
+
+    case tt._yield:
+    case tt.name: {
+      state.type = tt.name;
+      parseBindingIdentifier(isBlockScope);
+      return;
+    }
+
+    case tt.bracketL: {
+      next();
+      parseBindingList(tt.bracketR, isBlockScope, true /* allowEmpty */);
+      return;
+    }
+
+    case tt.braceL:
+      parseObj(true, isBlockScope);
+      return;
+
+    default:
+      unexpected();
+  }
+}
+
+export function parseBindingList(
+  close,
+  isBlockScope,
+  allowEmpty = false,
+  allowModifiers = false,
+  contextId = 0,
+) {
+  let first = true;
+
+  let hasRemovedComma = false;
+  const firstItemTokenIndex = state.tokens.length;
+
+  while (!eat(close) && !state.error) {
+    if (first) {
+      first = false;
+    } else {
+      expect(tt.comma);
+      state.tokens[state.tokens.length - 1].contextId = contextId;
+      // After a "this" type in TypeScript, we need to set the following comma (if any) to also be
+      // a type token so that it will be removed.
+      if (!hasRemovedComma && state.tokens[firstItemTokenIndex].isType) {
+        state.tokens[state.tokens.length - 1].isType = true;
+        hasRemovedComma = true;
+      }
+    }
+    if (allowEmpty && match(tt.comma)) {
+      // Empty item; nothing further to parse for this item.
+    } else if (eat(close)) {
+      break;
+    } else if (match(tt.ellipsis)) {
+      parseRest(isBlockScope);
+      parseAssignableListItemTypes();
+      // Support rest element trailing commas allowed by TypeScript <2.9.
+      eat(TokenType.comma);
+      expect(close);
+      break;
+    } else {
+      parseAssignableListItem(allowModifiers, isBlockScope);
+    }
+  }
+}
+
+function parseAssignableListItem(allowModifiers, isBlockScope) {
+  if (allowModifiers) {
+    tsParseModifiers([
+      ContextualKeyword._public,
+      ContextualKeyword._protected,
+      ContextualKeyword._private,
+      ContextualKeyword._readonly,
+      ContextualKeyword._override,
+    ]);
+  }
+
+  parseMaybeDefault(isBlockScope);
+  parseAssignableListItemTypes();
+  parseMaybeDefault(isBlockScope, true /* leftAlreadyParsed */);
+}
+
+function parseAssignableListItemTypes() {
+  if (isFlowEnabled) {
+    flowParseAssignableListItemTypes();
+  } else if (isTypeScriptEnabled) {
+    tsParseAssignableListItemTypes();
+  }
+}
+
+// Parses assignment pattern around given atom if possible.
+export function parseMaybeDefault(isBlockScope, leftAlreadyParsed = false) {
+  if (!leftAlreadyParsed) {
+    parseBindingAtom(isBlockScope);
+  }
+  if (!eat(tt.eq)) {
+    return;
+  }
+  const eqIndex = state.tokens.length - 1;
+  parseMaybeAssign();
+  state.tokens[eqIndex].rhsEndIndex = state.tokens.length;
+}