added child_process device

lib/devices/child_process._js

@@ -0,0 +1,33 @@
+"use strict";
+
+var node = require('./node');
+
+module.exports = {
+	/// !doc
+	/// ## EZ Stream wrappers for node child processes
+	/// 
+	/// `var ez = require('ez-streams');`
+	/// 
+	/// * `reader = ez.devices.child_process.reader(proc, options)`  
+	///   wraps a node.js child process as an EZ reader.  
+	///   For a full description of the options, see `ReadableStream` in
+	///   https://github.com/Sage/streamline-streams/blob/master/lib/streams.md 
+	reader: function(proc, options) {
+		var stdout = node.reader(proc.stdout, options);
+		var stderr = node.reader(proc.stderr, options);
+		if (options.dataHandler) stdout = options.dataHandler(stdout);
+		if (options.errorHandler) stderr = options.errorHandler(stderr);
+		if (options.errorPrefix || options.errorThrow) stderr = stderr.map(function(_, data) {
+			if (options.errorThrow) throw new Error((options.errorPrefix || "") + data);
+			return options.errorPrefix + data;
+		});
+		return stdout.join(stderr);
+	},
+	/// * `writer = ez.devices.child_process.writer(proc, options)`  
+	///   wraps a node.js child process as an EZ writer.  
+	///   For a full description of the options, see `WritableStream` in
+	///   https://github.com/Sage/streamline-streams/blob/master/lib/streams.md 
+	writer: function(proc, options) {
+		return node.writer(proc.stdin, options);
+	},
+};

lib/devices/child_process.md

@@ -0,0 +1,12 @@
+## EZ Stream wrappers for node child processes
+
+`var ez = require('ez-streams');`
+
+* `reader = ez.devices.child_process.reader(proc, options)`  
+  wraps a node.js child process as an EZ reader.  
+  For a full description of the options, see `ReadableStream` in
+  https://github.com/Sage/streamline-streams/blob/master/lib/streams.md 
+* `writer = ez.devices.child_process.writer(proc, options)`  
+  wraps a node.js child process as an EZ writer.  
+  For a full description of the options, see `WritableStream` in
+  https://github.com/Sage/streamline-streams/blob/master/lib/streams.md