Updated guide

guide/src/README.md

@@ -5,8 +5,10 @@ interoperability with the arrow format.
 
 The typical use-case for this library is to perform CPU and memory-intensive analytics in a format that supports heterogeneous data structures, null values, and IPC and FFI interfaces across languages.
 
-Arrow2 is divided into three main parts: 
+Arrow2 is divided into 5 main parts: 
 
 * a [low-level API](./low_level.md) to efficiently operate with contiguous memory regions;
 * a [high-level API](./high_level.md) to operate with arrow arrays;
-* a [metadata API](./metadata.md) to declare and operate with logical types and metadata.
+* a [metadata API](./metadata.md) to declare and operate with logical types and metadata;
+* a [compute API](./compute.md) with operators to operate over arrays;
+* an [IO API](./io/README.md) with interfaces to read from, and write to, other formats.

guide/src/io/json_read.md

@@ -14,3 +14,16 @@ This crate also supports reading JSON, at the expense of being unable to read th
 ```rust
 {{#include ../../../examples/json_read.rs}}
 ```
+
+## Metadata and inference
+
+This crate uses the following mapping between Arrow's data type and JSON:
+
+| `JSON` | `DataType` |
+| ------ | ---------- |
+| Bool   | Boolean    |
+| Int    | Int64      |
+| Float  | Float64    |
+| String | Utf8       |
+| List   | List       |
+| Object | Struct     |

guide/src/io/json_write.md

@@ -1,8 +1,14 @@
 # Write JSON
 
-When compiled with feature `io_json`, you can use this crate to write JSON files.
-The following example writes a batch as a JSON file:
+When compiled with feature `io_json`, you can use this crate to write JSON.
+The following example writes an array to JSON:
 
 ```rust
 {{#include ../../../examples/json_write.rs}}
 ```
+
+Likewise, you can also use it to write to NDJSON:
+
+```rust
+{{#include ../../../examples/ndjson_write.rs}}
+```

tests/it/io/json/mod.rs

@@ -11,7 +11,6 @@ fn write_batch(array: Box<dyn Array>) -> Result<Vec<u8>> {
     let mut serializer = json_write::Serializer::new(vec![Ok(array)].into_iter(), vec![]);
 
     let mut buf = vec![];
-    json_write::write(&mut buf, &mut serializer);
-
+    json_write::write(&mut buf, &mut serializer)?;
     Ok(buf)
 }