add args() plugin

Makefile

@@ -4,6 +4,7 @@ REPORTER=spec
 test:
 	@./node_modules/.bin/mocha \
 		--require should \
+		--bail \
 		--reporter $(REPORTER)
 
 test-cov: lib-cov

Readme.md

@@ -139,6 +139,15 @@ yields:
 { "upload path": "/www/example.com/tmp" }
 ```
 
+### eson.args([args])
+
+  Parse from the given `args` or __ARGV__. For example if you have a setting
+  named "dev ui" with a default value of `false`, `--dev-ui` would enable it,
+  or `--dev-ui yes` would provide the value "yes" which is of course also truthy.
+
+  To compliment `--NAME` you may also negate this, if "dev ui" is enabled by default
+  then you may use `--no-dev-ui` to disable it.
+
 ### eson.glob
 
   The glob plugin allows you to specify glob strings, prefixed by "glob":

lib/eson.js

@@ -23,6 +23,7 @@ exports.version = '0.0.1';
 
 exports.ms = require('./plugins/ms');
 exports.env = require('./plugins/env');
+exports.args = require('./plugins/args');
 exports.glob = require('./plugins/glob');
 exports.bools = require('./plugins/bools');
 exports.replace = require('./plugins/replace');

lib/plugins/args.js

@@ -0,0 +1,30 @@
+
+/**
+ * Allow ARGV to take precedence over `val`, supports:
+ * 
+ *   --NAME
+ *   --NAME value
+ *   --no-NAME
+ * 
+ */
+
+module.exports = function(args){
+  args = args || process.argv.slice(1);
+  return function(key, val){
+    var name = key.split(' ').join('-');
+
+    for (var i = 0, len = args.length; i < len; ++i) {
+      // --NAME
+      if (args[i] == '--' + name) {
+        // --NAME val
+        if (args[i + 1] && '-' != args[i + 1]) return args[++i];
+        return true;
+      }
+
+      // --no-NAME
+      if (args[i] == '--no-' + name) return false;
+    }
+
+    return val;
+  };
+};

test/args.js

@@ -0,0 +1,23 @@
+
+var Parser = require('../')
+  , args = Parser.args;
+
+describe('args', function(){
+  it('should support --NAME', function(){
+    var fn = args(['foo', 'bar']);
+    fn('dev ui', false).should.be.false;
+
+    fn = args(['foo', '--dev-ui']);
+    fn('dev ui', false).should.be.true;
+  })
+
+  it('should support --no-NAME', function(){
+    var fn = args(['foo', '--no-dev-ui']);
+    fn('dev ui', true).should.be.false;
+  })
+
+  it('should support --NAME val', function(){
+    var fn = args(['foo', '--dev-ui', 'yes']);
+    fn('dev ui', false).should.equal('yes');
+  })
+})