From acb4dec96750b0771c63f7b129e0108815e2d724 Mon Sep 17 00:00:00 2001
From: Mark Edgar <medgar123@gmail.com>
Date: Wed, 26 Oct 2011 09:43:24 +0200
Subject: [PATCH] Disallow trailing commas. Clean up EXPECTED messages.

---
 parse.sh                                | 87 +++++++++++++------------
 test/invalid/trailing_array_comma.json  |  1 +
 test/invalid/trailing_object_comma.json |  1 +
 3 files changed, 49 insertions(+), 40 deletions(-)
 create mode 100644 test/invalid/trailing_array_comma.json
 create mode 100644 test/invalid/trailing_object_comma.json

diff --git a/parse.sh b/parse.sh
index 661f25e..b469dc5 100644
--- a/parse.sh
+++ b/parse.sh
@@ -19,22 +19,24 @@ parse_array () {
   local index=0
   local ary=''
   read -r token
-  while true;
-  do
-    case "$token" in
-      ']') break ;;
-    esac
-    parse_value "$1" "$index"
-    let index=$index+1
-    ary="$ary""$value" 
-    read -r token
-    case "$token" in
-      ']') break ;;
-      ',') ary="$ary", ;;
-      *) throw "EXPECTED ] or , GOT ${token:-EOF}" ;;
-    esac
-    read -r token
-  done
+  case "$token" in
+    ']') ;;
+    *)
+      while :
+      do
+        parse_value "$1" "$index"
+        let index=$index+1
+        ary="$ary""$value" 
+        read -r token
+        case "$token" in
+          ']') break ;;
+          ',') ary="$ary," ;;
+          *) throw "EXPECTED , or ] GOT ${token:-EOF}" ;;
+        esac
+        read -r token
+      done
+      ;;
+  esac
   value=`printf '[%s]' $ary`
 }
 
@@ -42,28 +44,33 @@ parse_object () {
   local key
   local obj=''
   read -r token
-  while :
-  do
-    case "$token" in
-      '}') break ;;
-      '"'*'"') key=$token ;;
-      *) throw "EXPECTED STRING, GOT ${token:-EOF}" ;;
-    esac
-    read -r token
-    case "$token" in
-      ':') ;;
-      *) throw "EXPECTED COLON, GOT ${token:-EOF}" ;;
-    esac
-    read -r token
-    parse_value "$1" "$key"
-    obj="$obj$key:$value"        
-    read -r token
-    case "$token" in
-      '}') break;;
-      ',') obj="$obj,"; read -r token ;;
-      *) throw "EXPECTED , or }, but got ${token:-EOF}" ;;
-    esac
-  done
+  case "$token" in
+    '}') ;;
+    *)
+      while :
+      do
+        case "$token" in
+          '"'*'"') key=$token ;;
+          *) throw "EXPECTED string GOT ${token:-EOF}" ;;
+        esac
+        read -r token
+        case "$token" in
+          ':') ;;
+          *) throw "EXPECTED : GOT ${token:-EOF}" ;;
+        esac
+        read -r token
+        parse_value "$1" "$key"
+        obj="$obj$key:$value"        
+        read -r token
+        case "$token" in
+          '}') break ;;
+          ',') obj="$obj," ;;
+          *) throw "EXPECTED , or } GOT ${token:-EOF}" ;;
+        esac
+        read -r token
+      done
+    ;;
+  esac
   value=`printf '{%s}' "$obj"`
 }
 
@@ -73,7 +80,7 @@ parse_value () {
     '{') parse_object "$jpath" ;;
     '[') parse_array  "$jpath" ;;
     # At this point, the only valid single-character tokens are digits.
-    ''|[^0-9]) throw "EXPECTED value, GOT ${token:-EOF}" ;;
+    ''|[^0-9]) throw "EXPECTED value GOT ${token:-EOF}" ;;
     *) value=$token ;;
   esac
   printf "[%s]\t%s\n" "$jpath" "$value"
@@ -85,6 +92,6 @@ parse () {
   read -r token
   case "$token" in
     '') ;;
-    *) throw "EXPECTED EOF, GOT $token" ;;
+    *) throw "EXPECTED EOF GOT $token" ;;
   esac
 }
diff --git a/test/invalid/trailing_array_comma.json b/test/invalid/trailing_array_comma.json
new file mode 100644
index 0000000..e2ae501
--- /dev/null
+++ b/test/invalid/trailing_array_comma.json
@@ -0,0 +1 @@
+[1,2,3,]
diff --git a/test/invalid/trailing_object_comma.json b/test/invalid/trailing_object_comma.json
new file mode 100644
index 0000000..71d0f1b
--- /dev/null
+++ b/test/invalid/trailing_object_comma.json
@@ -0,0 +1 @@
+{"a":1,"b":2,"c":3,}