src/parser/tests/basics.test.ts

@@ -36,6 +36,19 @@ describe('Identifier', () => {
       FunctionCallOrIdentifier
         Identifier 𝜋`)
   })
+
+  test('parses identifiers with queries', () => {
+    expect('even? 20').toMatchTree(`
+      FunctionCall
+        Identifier even?
+        PositionalArg
+          Number 20`)
+
+    expect('even?').toMatchTree(`
+      FunctionCallOrIdentifier
+        Identifier even?`)
+  })
+
 })
 
 describe('Unicode Symbol Support', () => {

src/parser/tokenizer.ts

@@ -119,7 +119,7 @@ const consumeWordToken = (
     }
 
     // Track identifier validity: must be lowercase, digit, dash, or emoji/unicode
-    if (!isLowercaseLetter(ch) && !isDigit(ch) && ch !== 45 /* - */ && !isEmojiOrUnicode(ch)) {
+    if (!isLowercaseLetter(ch) && !isDigit(ch) && ch !== 45 /* - */ && ch !== 63 /* ? */ && !isEmojiOrUnicode(ch)) {
       if (!canBeWord) break
       isValidIdentifier = false
     }