Update json parser

- Support parsing null values, negatives, and decimals
- Output null values for uninitialized variables
- Output empty strings correctly

diff --git a/json.awk b/json.awk
index 59b5eb5c5f7c53ae9f9b0af5762160bd96d38867..6408253a49ce0273620edca1d2e3a0869855721c 100644 (file)
--- a/json.awk
+++ b/json.awk
@@ -19,7 +19,6 @@
 #      \t
 #      \u four-hex-digits
 
-
 # Helpers
 function json_gettype(value,   key, sort, n, i)
 {
@@ -33,6 +32,8 @@ function json_gettype(value,   key, sort, n, i)
                                return "object"
                return "array"
        } else {
+               if (value == 0 && value == "")
+                       return "null"
                if (value == value + 0)
                        return "number"
                if (value == value "")
@@ -71,6 +72,7 @@ function json_write_value(value, pad)
                case "array":  return json_write_array(value, pad)
                case "number": return json_write_number(value)
                case "string": return json_write_string(value)
+               case "null":   return "null"
                default:       return "error"
        }
 }
@@ -116,7 +118,7 @@ function json_tokenize(str, tokens,   i, items, table, type, found)
 {
        table["term"]  = "^[\\[\\]{}:,]"
        table["str"]   = "^\"[^\"]*\""
-       table["num"]   = "^[0-9]+"
+       table["num"]   = "^[+-]?[0-9]+(.[0-9]+)?"
        table["var"]   = "^(true|false|null)"
        table["space"] = "^[ \\t\\n]+"
        i = 0
@@ -227,16 +229,20 @@ function json_parse_number(tokens, i, value, key,   text)
 function json_parse_string(tokens, i, value, key,   text)
 {
        text = tokens[i++]["text"]
-       text = substr(text, 2, length(text)-2)
+       len  = length(text);
+       text = len == 2 ? "" : substr(text, 2, len-2)
        json_copy(value, key, text)
-       #print "parse_string: " text
+       #print "parse_string: [" text "]"
        return i
 }
 
-function json_parse_var(tokens, i, value, key,   text)
+function json_parse_var(tokens, i, value, key,   text, null)
 {
-       text = tokens[i++]["text"]
-       json_copy(value, key, text == "true")
+       switch (tokens[i++]["text"]) {
+               case "true":  json_copy(value, key, 1==1); break;
+               case "false": json_copy(value, key, 1==2); break;
+               case "null":  json_copy(value, key, null); break;
+       }
        #print "parse_var: " text " -> " text == "true"
        return i
 }
@@ -298,15 +304,18 @@ function json_test_read()
 {
        json_tokenize("[8, \"abc\", 9]", tokens)
        json_parse_value(tokens, 0, array, 0)
-       json_print write_value(array[0])
+       print json_write_value(array[0])
 
        json_tokenize("{\"abc\": 1, \"def\": 2}", tokens)
        json_parse_value(tokens, 0, array, 0)
-       json_print write_value(array[0])
+       print json_write_value(array[0])
 
-       json = "{ \"first\":  { \"arr\":    [ \"zero\",         " \
-              "                              \"one\",          " \
-              "                              \"two\" ],        " \
+       json = "{ \"first\":  { \"arr\":    [ \"\",             " \
+              "                              -1,               " \
+              "                              1.2,              " \
+              "                              true,             " \
+              "                              false,            " \
+              "                              null    ],        " \
               "                \"number\": 42,                 " \
               "                \"obj\":    { \"A\": \"a!\",    " \
               "                              \"B\": \"b!\",    " \