Make default field type to be any (#13)

* Fixed default field type

* Updated any type

* Updated wording

* Fixed typo

Co-authored-by: Peter Desmet <[email protected]>

* Aded an example

* Added note that any can be omitted

* Update content/docs/specifications/table-schema.md

Co-authored-by: Pieter Huybrechts <[email protected]>

* Update content/docs/specifications/table-schema.md

Co-authored-by: Peter Desmet <[email protected]>

* Update content/docs/specifications/table-schema.md

Co-authored-by: Peter Desmet <[email protected]>

---------

Co-authored-by: Peter Desmet <[email protected]>
Co-authored-by: Pieter Huybrechts <[email protected]>
Co-authored-by: Peter Desmet <[email protected]>

content/docs/specifications/table-schema.md

@@ -188,15 +188,14 @@ A data consumer `MUST`:
 
 ### Types and Formats
 
-`type` and `format` properties are used to give The type of the field (string, number etc) - see below for
-more detail. If type is not provided a consumer `SHOULD` assume a type of "string".
+`type` and `format` properties are used to give the type of the field (string, number, etc.) - see below for more detail. If type is not provided a consumer `MUST` utilize the `any` type for the field instead of inferring it from the field's values.
 
 A field's `type` property is a string indicating the type of this field.
 
 A field's `format` property is a string, indicating a format for the field type.
 
 Both `type` and `format` are optional: in a field descriptor, the absence of a
-`type` property indicates that the field is of the type "string", and the
+`type` property indicates that the field is of the type "any", and the
 absence of a `format` property indicates that the field's type `format` is
 "default".
 
@@ -391,11 +390,48 @@ The field contains a JSON object according to GeoJSON or TopoJSON spec.
 
 #### any
 
-Any `type` or `format` is accepted. When converting from physical to logical representation, the behaviour `SHOULD` be similar to String field type.
+The field contains values of a unspecified or mixed type. A data consumer `MUST NOT` perform any processing on this field's values and `MUST` interpret them as it is in the data source. This data type is directly modelled on the concept of the `any` type of strongly typed object-oriented languages like [TypeScript](https://www.typescriptlang.org/docs/handbook/2/everyday-types.html#any).
 
-[strptime]: https://docs.python.org/2/library/datetime.html#strftime-strptime-behavior
-[iso8601-duration]: https://en.wikipedia.org/wiki/ISO_8601#Durations
-[xsd-duration]: http://www.w3.org/TR/xmlschema-2/#duration
+For example, having a Table Schema below:
+
+```json
+{
+  "fields": [
+    { "name": "id", "type": "any" },
+    { "name": "name", "type": "any" }
+  ]
+}
+```
+
+This CSV data file will have logical values as below:
+
+```csv
+id,name
+1,apple
+2,orange
+```
+
+```javascript
+{id: "1", name: "apple"}
+{id: "2", name: "orange"}
+```
+
+While this JSON data file will have logical values as below:
+
+```json
+[
+  ["id", "name"]
+  [1, "apple"]
+  [2, "orange"]
+]
+```
+
+```javascript
+{id: 1, name: "apple"}
+{id: 2, name: "orange"}
+```
+
+Note, that for the CSV data source the `id` field is interpreted as a string because CSV supports only one data type i.e. string, and for the JSON data source the `id` field is interpreted as an integer because JSON supports a numeric data type and the value was declared as an integer. Also, for the Table Schema above a `type` property for each field can be omitted as it is a default field type.
 
 ### Rich Types
 
@@ -817,3 +853,6 @@ Table Schema draws content and/or inspiration from, among others, the following
 [dspl]: https://developers.google.com/public-data/docs/schema/dspl18
 [html5 forms]: http://www.whatwg.org/specs/web-apps/current-work/#attr-input-typ
 [elasticsearch]: http://www.elasticsearch.org/guide/reference/mapping/
+[strptime]: https://docs.python.org/2/library/datetime.html#strftime-strptime-behavior
+[iso8601-duration]: https://en.wikipedia.org/wiki/ISO_8601#Durations
+[xsd-duration]: http://www.w3.org/TR/xmlschema-2/#duration