Treat special identifiers as variables

Fixes #9

Author: Fidget-Spinner

src/parser.ts

@@ -47,6 +47,11 @@ import {ParserErrors} from "./errors";
 type Expr = ExprNS.Expr;
 type Stmt = StmtNS.Stmt;
 
+const PSEUD_NAMES = [
+    TokenType.TRUE,
+    TokenType.FALSE,
+    TokenType.NONE,
+]
 
 export class Parser {
     private readonly source: string;
@@ -148,7 +153,8 @@ export class Parser {
     private stmt(): Stmt {
         if (this.check(TokenType.DEF, TokenType.FOR, TokenType.IF, TokenType.WHILE)) {
             return this.compound_stmt();
-        } else if (this.check(TokenType.NAME, TokenType.NUMBER, TokenType.PASS, TokenType.BREAK, TokenType.CONTINUE,
+        } else if (this.check(TokenType.NAME, ...PSEUD_NAMES, TokenType.NUMBER,
+            TokenType.PASS, TokenType.BREAK, TokenType.CONTINUE,
             TokenType.RETURN, TokenType.FROM, TokenType.GLOBAL, TokenType.NONLOCAL,
             TokenType.ASSERT, TokenType.LPAR, ...SPECIAL_IDENTIFIER_TOKENS)) {
             return this.simple_stmt();
@@ -496,7 +502,7 @@ export class Parser {
             return new ExprNS.Literal(startToken, this.previous(), Number(this.previous().lexeme));
         }
 
-        if (this.match(TokenType.NAME)) {
+        if (this.match(TokenType.NAME, ...PSEUD_NAMES)) {
             return new ExprNS.Variable(startToken, this.previous(), this.previous());
         }
 

src/tests/regression.test.ts

@@ -27,6 +27,14 @@ def foo(
     pass
 
     pass
+`;
+        toEstreeAST(text);
+    })
+    test('Issue #9', () => {
+        const text = `
+add_one = lambda : None
+add_one = lambda : True
+add_one = lambda : False
 `;
         toEstreeAST(text);
     })

test.py

@@ -1,6 +1 @@
-def foo(
-    a, b
-):
-    pass
-
-    pass
+add_one = lambda : None