Support ."foo" syntax for accessing fields. See #141.

docs/content/3.manual/manual.yml

@@ -160,10 +160,13 @@ sections:
       - title: "`.foo`"
         body: |
           
-          The simplest *useful* filter is .foo. When given a
+          The simplest *useful* filter is `.foo`. When given a
           JSON object (aka dictionary or hash) as input, it produces
           the value at the key "foo", or null if there's none present.
 
+          If the key contains special characters, you need to surround
+          it with double quotes like this: `."foo$"`.
+          
         examples:
           - program: '.foo'
             input: '{"foo": 42, "bar": "less interesting data"}'
@@ -171,6 +174,9 @@ sections:
           - program: '.foo'
             input: '{"notfoo": true, "alsonotfoo": false}'
             output: ['null']
+          - program: '."foo"'
+            input: '{"foo": 42}'
+            output: [42]
 
       - title: "`.[foo]`, `.[2]`, `.[10:15]`"
         body: |

parser.y

@@ -406,6 +406,12 @@ Term FIELD {
 FIELD { 
   $$ = gen_index(gen_noop(), gen_const($1)); 
 } |
+Term '.' String {
+  $$ = gen_index($1, $3);
+} |
+'.' String {
+  $$ = gen_index(gen_noop(), $2);
+} |
 '.' error {
   FAIL(@$, "try .[\"field\"] instead of .field for unusually named fields");
   $$ = gen_noop();

tests/all.test

@@ -115,6 +115,10 @@ null
 {"foo": {"bar": 42}, "bar": "badvalue"}
 42
 
+."foo"."bar"
+{"foo": {"bar": 20}}
+20
+
 
 #
 # Multiple outputs, iteration