fix(decode): handle bare list marker as empty object

Author: pragyanatvade

src/com/vadelabs/toon/decode/arrays.cljc

@@ -3,17 +3,15 @@
 
   Handles inline, tabular, and list array formats."
   (:require
-    [clojure.string :as str]
-    [com.vadelabs.toon.constants :as const]
-    [com.vadelabs.toon.decode.parser :as parser]
-    [com.vadelabs.toon.decode.scanner :as scanner]
-    [com.vadelabs.toon.utils :as str-utils]))
-
+   [clojure.string :as str]
+   [com.vadelabs.toon.constants :as const]
+   [com.vadelabs.toon.decode.parser :as parser]
+   [com.vadelabs.toon.decode.scanner :as scanner]
+   [com.vadelabs.toon.utils :as str-utils]))
 
 ;; Forward declaration for mutual recursion
 (declare list-item)
 
-
 ;; ============================================================================
 ;; Validation Helpers
 ;; ============================================================================
@@ -48,7 +46,6 @@
                        :actual actual
                        :suggestion (str "Update header to " header-fix " or add " (- expected actual) " more" type-suffix)})))))
 
-
 ;; ============================================================================
 ;; Inline Primitive Array Decoding
 ;; ============================================================================
@@ -77,7 +74,6 @@
        (validate-array-length! length (count values) strict :inline)
        values))))
 
-
 ;; ============================================================================
 ;; Tabular Array Decoding
 ;; ============================================================================
@@ -96,7 +92,6 @@
   (let [tokens (parser/delimited-values row-content delimiter)]
     (mapv #(parser/primitive-token % strict) tokens)))
 
-
 (defn- analyze-line-positions
   "Analyzes positions of colon and delimiter in a line.
 
@@ -111,7 +106,6 @@
     {:colon-pos (str-utils/unquoted-char content \:)
      :delim-pos (str-utils/unquoted-char content delim-char)}))
 
-
 (defn- delimiter-before-colon?
   "Checks if delimiter appears before colon in position analysis.
 
@@ -123,7 +117,6 @@
   [{:keys [colon-pos delim-pos]}]
   (and colon-pos delim-pos (< delim-pos colon-pos)))
 
-
 (defn- peek-next-line-has-delimiter-first?
   "Checks if next line at same depth has delimiter before colon.
 
@@ -139,7 +132,6 @@
     (delimiter-before-colon? (analyze-line-positions (:content next-line) delimiter))
     false))
 
-
 (defn- row-or-key-value?
   "Determines if a line is a data row or key-value line.
 
@@ -186,7 +178,6 @@
        :else
        :key-value))))
 
-
 (defn tabular-array
   "Decodes a tabular array into objects.
 
@@ -235,7 +226,6 @@
                       (conj objects obj)
                       (inc row-count))))))))))
 
-
 ;; ============================================================================
 ;; List Array Decoding
 ;; ============================================================================
@@ -272,8 +262,9 @@
          (do
            (validate-array-length! length item-count strict :list)
            [items remaining-cursor])
-         ;; Check if line starts with list marker
-         (if-not (str/starts-with? (:content line) const/list-item-prefix)
+         ;; Check if line starts with list marker (prefix "- " or bare "-")
+         (if-not (or (str/starts-with? (:content line) const/list-item-prefix)
+                     (= (:content line) const/list-item-marker))
            ;; No list marker: end of list
            (do
              (validate-array-length! length item-count strict :list)

src/com/vadelabs/toon/decode/items.cljc

@@ -1,14 +1,13 @@
 (ns com.vadelabs.toon.decode.items
   "List item type detection and decoding for TOON format."
   (:require
-    [clojure.string :as str]
-    [com.vadelabs.toon.constants :as const]
-    [com.vadelabs.toon.decode.arrays :as arrays]
-    [com.vadelabs.toon.decode.objects :as objects]
-    [com.vadelabs.toon.decode.parser :as parser]
-    [com.vadelabs.toon.decode.scanner :as scanner]
-    [com.vadelabs.toon.utils :as str-utils]))
-
+   [clojure.string :as str]
+   [com.vadelabs.toon.constants :as const]
+   [com.vadelabs.toon.decode.arrays :as arrays]
+   [com.vadelabs.toon.decode.objects :as objects]
+   [com.vadelabs.toon.decode.parser :as parser]
+   [com.vadelabs.toon.decode.scanner :as scanner]
+   [com.vadelabs.toon.utils :as str-utils]))
 
 ;; ============================================================================
 ;; List Item Type Detection
@@ -28,7 +27,6 @@
     :else
     :primitive))
 
-
 ;; ============================================================================
 ;; List Item Decoding
 ;; ============================================================================
@@ -46,24 +44,27 @@
   Returns:
     [decoded-value, new-cursor]"
   [line cursor depth delimiter strict]
-  (let [content (:content line)
-        ;; Remove list marker prefix ("- ")
-        after-marker (subs content (count const/list-item-prefix))
-        item-type (list-item-type after-marker)]
-    (case item-type
-      :array
-      ;; Inline array: "- [3]: a,b,c"
-      (let [header-info (parser/array-header-line after-marker)
-            items (arrays/inline-primitive-array header-info strict)
-            new-cursor (scanner/advance-cursor cursor)]
-        [items new-cursor])
+  (let [content (:content line)]
+    ;; Bare list marker: always an empty object
+    (if (= content const/list-item-marker)
+      [{} (scanner/advance-cursor cursor)]
+      ;; Normal list item with content after "- "
+      (let [after-marker (subs content (count const/list-item-prefix))
+            item-type (list-item-type after-marker)]
+        (case item-type
+          :array
+          ;; Inline array: "- [3]: a,b,c"
+          (let [header-info (parser/array-header-line after-marker)
+                items (arrays/inline-primitive-array header-info strict)
+                new-cursor (scanner/advance-cursor cursor)]
+            [items new-cursor])
 
-      :object
-      ;; Object with first field on hyphen line
-      (objects/object-from-list-item line cursor depth delimiter strict list-item)
+          :object
+          ;; Object with first field on hyphen line
+          (objects/object-from-list-item line cursor depth delimiter strict list-item)
 
-      :primitive
-      ;; Simple primitive value
-      (let [value (parser/primitive-token after-marker strict)
-            new-cursor (scanner/advance-cursor cursor)]
-        [value new-cursor]))))
+          :primitive
+          ;; Simple primitive value
+          (let [value (parser/primitive-token after-marker strict)
+                new-cursor (scanner/advance-cursor cursor)]
+            [value new-cursor]))))))

test/com/vadelabs/toon/decode/items_test.cljc

@@ -1,11 +1,10 @@
 (ns com.vadelabs.toon.decode.items-test
   "Tests for list item type detection and decoding."
   (:require
-    #?(:clj [clojure.test :refer [deftest is testing]]
-       :cljs [cljs.test :refer [deftest is testing]])
-    [com.vadelabs.toon.decode.items :as items]
-    [com.vadelabs.toon.decode.scanner :as scanner]))
-
+   #?(:clj [clojure.test :refer [deftest is testing]]
+      :cljs [cljs.test :refer [deftest is testing]])
+   [com.vadelabs.toon.decode.items :as items]
+   [com.vadelabs.toon.decode.scanner :as scanner]))
 
 ;; ============================================================================
 ;; List Item Type Detection Tests
@@ -26,7 +25,6 @@
       (is (= :primitive (#'items/list-item-type "42")))
       (is (= :primitive (#'items/list-item-type "true"))))))
 
-
 ;; ============================================================================
 ;; List Item Decoding Tests
 ;; ============================================================================
@@ -40,7 +38,6 @@
           [result _] (items/list-item line cursor 0 "," true)]
       (is (= "hello" result)))))
 
-
 (deftest list-item-array-test
   (testing "Decode array list item"
     (let [input "- [3]: 1,2,3"
@@ -50,7 +47,6 @@
           [result _] (items/list-item line cursor 0 "," true)]
       (is (= [1.0 2.0 3.0] result)))))
 
-
 (deftest list-item-object-test
   (testing "Decode object list item"
     (let [input "- id: 1\n  name: Alice"
@@ -60,7 +56,6 @@
           [result _] (items/list-item line cursor 0 "," true)]
       (is (= {"id" 1.0 "name" "Alice"} result)))))
 
-
 (deftest list-item-multiline-object-test
   (testing "Decode multi-line object list item"
     (let [input "- name: Bob\n  age: 25\n  active: true"
@@ -69,3 +64,26 @@
           [line _] (scanner/next-cursor cursor)
           [result _] (items/list-item line cursor 0 "," true)]
       (is (= {"name" "Bob" "age" 25.0 "active" true} result)))))
+
+;; ============================================================================
+;; Bare List Item Tests
+;; ============================================================================
+
+(deftest bare-list-item-test
+  (testing "Bare list marker decodes to empty object"
+    (let [input "-"
+          scan-result (scanner/to-parsed-lines input)
+          cursor (scanner/cursor-from-scan-result scan-result)
+          [line _] (scanner/next-cursor cursor)
+          [result _] (items/list-item line cursor 0 "," true)]
+      (is (= {} result)))))
+
+(deftest bare-list-item-with-trailing-space-test
+  (testing "Bare list marker with trailing space decodes to empty object"
+    ;; Note: scanner trims content, so "- " becomes "-"
+    (let [input "- "
+          scan-result (scanner/to-parsed-lines input)
+          cursor (scanner/cursor-from-scan-result scan-result)
+          [line _] (scanner/next-cursor cursor)
+          [result _] (items/list-item line cursor 0 "," true)]
+      (is (= {} result)))))