doc refactor: modules

doc/api/modules.markdown

@@ -1,4 +1,6 @@
-## Modules
+# Modules
+
+<!--name=module-->
 
 Node has a simple module loading system.  In Node, files and modules are in
 one-to-one correspondence.  As an example, `foo.js` loads the module
@@ -30,7 +32,11 @@ Variables
 local to the module will be private. In this example the variable `PI` is
 private to `circle.js`.
 
-### Cycles
+The module system is implemented in the `require("module")` module.
+
+## Cycles
+
+<!--type=misc-->
 
 When there are circular `require()` calls, a module might not be
 done being executed when it is returned.
@@ -84,7 +90,9 @@ The output of this program would thus be:
 If you have cyclic module dependencies in your program, make sure to
 plan accordingly.
 
-### Core Modules
+## Core Modules
+
+<!--type=misc-->
 
 Node has several modules compiled into the binary.  These modules are
 described in greater detail elsewhere in this documentation.
@@ -95,7 +103,9 @@ Core modules are always preferentially loaded if their identifier is
 passed to `require()`.  For instance, `require('http')` will always
 return the built in HTTP module, even if there is a file by that name.
 
-### File Modules
+## File Modules
+
+<!--type=misc-->
 
 If the exact filename is not found, then node will attempt to load the
 required filename with the added extension of `.js`, `.json`, and then `.node`.
@@ -115,7 +125,9 @@ That is, `circle.js` must be in the same directory as `foo.js` for
 Without a leading '/' or './' to indicate a file, the module is either a
 "core module" or is loaded from a `node_modules` folder.
 
-### Loading from `node_modules` Folders
+## Loading from `node_modules` Folders
+
+<!--type=misc-->
 
 If the module identifier passed to `require()` is not a native module,
 and does not begin with `'/'`, `'../'`, or `'./'`, then node starts at the
@@ -137,7 +149,9 @@ this order:
 This allows programs to localize their dependencies, so that they do not
 clash.
 
-### Folders as Modules
+## Folders as Modules
+
+<!--type=misc-->
 
 It is convenient to organize programs and libraries into self-contained
 directories, and then provide a single entry point to that library.
@@ -165,7 +179,9 @@ example, then `require('./some-library')` would attempt to load:
 * `./some-library/index.js`
 * `./some-library/index.node`
 
-### Caching
+## Caching
+
+<!--type=misc-->
 
 Modules are cached after the first time they are loaded.  This means
 (among other things) that every call to `require('foo')` will get
@@ -179,7 +195,9 @@ dependencies to be loaded even when they would cause cycles.
 If you want to have a module execute code multiple times, then export a
 function, and call that function.
 
-#### Module Caching Caveats
+### Module Caching Caveats
+
+<!--type=misc-->
 
 Modules are cached based on their resolved filename.  Since modules may
 resolve to a different filename based on the location of the calling
@@ -187,8 +205,22 @@ module (loading from `node_modules` folders), it is not a *guarantee*
 that `require('foo')` will always return the exact same object, if it
 would resolve to different files.
 
+## The `module` Object
+
+<!-- type=var -->
+<!-- name=module -->
+
+* {Object}
+
+In each module, the `module` free variable is a reference to the object
+representing the current module.  In particular
+`module.exports` is the same as the `exports` object.
+`module` isn't actually a global but rather local to each module.
+
 ### module.exports
 
+* {Object}
+
 The `exports` object is created by the Module system. Sometimes this is not
 acceptable, many want their module to be an instance of some class. To do this
 assign the desired export object to `module.exports`. For example suppose we
@@ -227,7 +259,10 @@ y.js:
     console.log(x.a);
 
 
-### module.require
+### module.require(id)
+
+* `id` {String}
+* Return: {Object} `exports` from the resolved module
 
 The `module.require` method provides a way to load a module as if
 `require()` was called from the original module.
@@ -238,7 +273,47 @@ typically *only* available within a specific module's code, it must be
 explicitly exported in order to be used.
 
 
-### All Together...
+### module.id
+
+* {String}
+
+The identifier for the module.  Typically this is the fully resolved
+filename.
+
+
+### module.filename
+
+* {String}
+
+The fully resolved filename to the module.
+
+
+### module.loaded
+
+* {Boolean}
+
+Whether or not the module is done loading, or is in the process of
+loading.
+
+
+### module.parent
+
+* {Module Object}
+
+The module that required this one.
+
+
+### module.children
+
+* {Array}
+
+The module objects required by this one.
+
+
+
+## All Together...
+
+<!-- type=misc -->
 
 To get the exact filename that will be loaded when `require()` is called, use
 the `require.resolve()` function.
@@ -287,7 +362,9 @@ in pseudocode of what require.resolve does:
        c. let I = I - 1
     6. return DIRS
 
-### Loading from the global folders
+## Loading from the global folders
+
+<!-- type=misc -->
 
 If the `NODE_PATH` environment variable is set to a colon-delimited list
 of absolute paths, then node will search those paths for modules if they
@@ -307,7 +384,9 @@ These are mostly for historic reasons.  You are highly encouraged to
 place your dependencies locally in `node_modules` folders.  They will be
 loaded faster, and more reliably.
 
-### Accessing the main module
+## Accessing the main module
+
+<!-- type=misc -->
 
 When a file is run directly from Node, `require.main` is set to its
 `module`. That means that you can determine whether a file has been run
@@ -324,6 +403,8 @@ by checking `require.main.filename`.
 
 ## Addenda: Package Manager Tips
 
+<!-- type=misc -->
+
 The semantics of Node's `require()` function were designed to be general
 enough to support a number of sane directory structures. Package manager
 programs such as `dpkg`, `rpm`, and `npm` will hopefully find it possible to