From d636339abe5914882e88a949c5e3d39d2aa3d8c9 Mon Sep 17 00:00:00 2001
From: Matthias Beyer <mail@beyermatthias.de>
Date: Mon, 11 Jan 2016 17:13:09 +0100
Subject: [PATCH 1/3] doc: define runtime library

---
 doc/src/03100-lib-rt.md | 11 +++++++++++
 1 file changed, 11 insertions(+)
 create mode 100644 doc/src/03100-lib-rt.md

diff --git a/doc/src/03100-lib-rt.md b/doc/src/03100-lib-rt.md
new file mode 100644
index 00000000..67e6f10d
--- /dev/null
+++ b/doc/src/03100-lib-rt.md
@@ -0,0 +1,11 @@
+# librt {#sec:librt}
+
+The runtime library provides types and functions which MUST be used by the
+modules to implement the commandline interface, configuration file parsing and
+logging.
+
+The runtime library provides basic functionality for configuration file parsing
+and logging setup.
+The runtime library also provides helper functions for building a commandline
+interface.
+

From c8f0b26577fdb55136e485d0722388fb8e96c09e Mon Sep 17 00:00:00 2001
From: Matthias Beyer <mail@beyermatthias.de>
Date: Mon, 11 Jan 2016 18:02:31 +0100
Subject: [PATCH 2/3] doc: rt: Add chapter on configuration file

---
 doc/src/03100-lib-rt.md | 62 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/doc/src/03100-lib-rt.md b/doc/src/03100-lib-rt.md
index 67e6f10d..3053adeb 100644
--- a/doc/src/03100-lib-rt.md
+++ b/doc/src/03100-lib-rt.md
@@ -9,3 +9,65 @@ and logging setup.
 The runtime library also provides helper functions for building a commandline
 interface.
 
+## Configuration file {#sec:librt:cfg}
+
+The runtime library SHOULD read the configuration file, if it can be found.
+If the configuration file cannot be found, the following variables are set to
+their default values as shown in @tbl:librt:cfg:defaultvalues.
+
+| Variable       | Value                |
+| :------------- | :------------------- |
+| verbosity      | false                |
+| debugging      | false                |
+| store location | `$HOME/.imag/store/` |
+
+Table: Default values for configuration if configuration file unavailable
+{#tbl:librt:cfg:defaultvalues}
+
+### Location of the configuration file {#sec:librt:cfg:location}
+
+For the configuration file is searched at the following locations:
+
+1. Path: `$HOME/.imag/config`
+1. Path: `$HOME/.imag/config.toml`
+1. Path: `$HOME/.imag/imagrc`
+1. Path: `$HOME/.imag/imagrc.toml`
+1. Path: `$XDG_CONFIG_DIR/imag/config`
+1. Path: `$XDG_CONFIG_DIR/imag/config.toml`
+1. Path: `$XDG_CONFIG_DIR/imag/imagrc`
+1. Path: `$XDG_CONFIG_DIR/imag/imagrc.toml`
+1. Path in the environment variable `$IMAG_CONFIG`
+
+If neither of these configuration files are found, the program MUST USE the
+default values for the minimum required variables
+(@tbl:librt:cfg:defaultvalues).
+
+### Contents of the configuration file {#sec:librt:cfg:contents}
+
+The contents of the configuration file MUST BE encoded in Unicode UTF-8.
+The contents of the configuration file are structured as TOML, regardless of the
+file extension.
+
+The configuration file contains several sections:
+
+1. The `base` section, which contains basic variables
+   (@tbl:librt:cfg:contents:base)
+1. The `modules` section, which contains a section for each module.
+1. The `store` section, which contains configuration on the behaviour of the
+   store (@tbl:librt:cfg:contents:store)
+
+| Variable       | Type    |
+| :------------- | :------ |
+| verbosity      | boolean |
+| debugging      | boolean |
+| store location | Path    |
+
+Table: "Base" variables in the configuration file {#tbl:librt:cfg:contents:base}
+
+
+| Variable  | Type    | Meaning                                          |
+| :-------- | :------ | :----------------------------------------------- |
+| git-vcs   | boolean | Whether the store is version controlled with git |
+
+Table: "store" variables in the configuration file {#tbl:librt:cfg:contents:store}
+

From 6141c8499dce58eab247a3c92806150461ecf346 Mon Sep 17 00:00:00 2001
From: Matthias Beyer <mail@beyermatthias.de>
Date: Mon, 11 Jan 2016 17:13:20 +0100
Subject: [PATCH 3/3] doc: Add definition of modules

---
 doc/src/06000-modules.md | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/doc/src/06000-modules.md b/doc/src/06000-modules.md
index 3e7a06ce..0edf2667 100644
--- a/doc/src/06000-modules.md
+++ b/doc/src/06000-modules.md
@@ -1,2 +1,20 @@
 # Modules {#sec:modules}
 
+A module is a functionality of the program.
+
+A module MAY store data in the store (@sec:thestore).
+It MAY include user input in the data it stores in the store.
+A module MUST HAVE a commandline interface, though a module always consists of
+two parts:
+
+- A Library
+- A Binary, which
+    * is executable by the user
+    * implements a commandline frontend to the libray of the module
+
+By definition, the Binary depends on the Library.
+By definition, the Library depends on the libstore (@sec:libstore).
+
+A module MUST use the runtime library to implement the commandline
+interface as defined in @sec:librt.
+