Merge branch 'version-0.1.3' to master0.1.3

- Add documentation
- Fix docstrings & types of custom vars

Improve algorithm implementation
- Adjust next ef and interval depending on consecutive & total
failures/successes
- Fix bugs for custom reviews where last-interv would be 0

3 files changed, 909 insertions, 0 deletions

diff --git a/doc/gnosis.info b/doc/gnosis.info
new file mode 100644
index 0000000..fe0338a
--- /dev/null
+++ b/doc/gnosis.info
@@ -0,0 +1,350 @@
+This is gnosis.info, produced by makeinfo version 7.1 from gnosis.texi.
+
+INFO-DIR-SECTION Emacs misc features
+START-INFO-DIR-ENTRY
+* Gnosis (γνῶσις): (gnosis). Spaced Repetition System For Note Taking And Self-Testing.
+END-INFO-DIR-ENTRY
+
+
+File: gnosis.info,  Node: Top,  Next: Introduction,  Up: (dir)
+
+Gnosis User Manual
+******************
+
+Gnosis (γνῶσις), pronounced "noh-sis", _meaning knowledge in Greek_, is
+a spaced repetition system implementation for note taking and self
+testing.
+
+This manual is written for Gnosis version 0.1.3, released on 2023-01-18.
+
+   • Official manual: <https://thanosapollo.org/user-manual/gnosis>
+   • Git repositories:
+        • main: <https://git.thanosapollo.org/gnosis>
+        • sourcehut (mirror): <https://git.sr.ht/~thanosapollo/gnosis>
+
+* Menu:
+
+* Introduction::
+* Installation::
+* Adding notes::
+* Note Types::
+* Customization::
+
+-- The Detailed Node Listing --
+
+Installation
+
+* Using straight.el: Using straightel.
+* Installing manually from source::
+
+Note Types
+
+* Cloze::
+* Basic Type::
+* Double::
+* MCQ (Multiple Choice Question)::
+* y-or-n::
+
+Customization
+
+* Gnosis Algorithm Initial Interval::
+* Gnosis Algorithm Easiness Factor::
+* Gnosis Algorithm Forgetting Factor::
+
+
+
+File: gnosis.info,  Node: Introduction,  Next: Installation,  Prev: Top,  Up: Top
+
+1 Introduction
+**************
+
+Gnosis is a spaced repetition note taking and self testing system, where
+notes are taken in a Question/Answer/Explanation-like format & reviewed
+in spaced intervals.
+
+   Gnosis can help you better understand and retain the material by
+encouraging active engagement.  It also provides a clear structure for
+your notes & review sessions, making it easier to study.
+
+
+File: gnosis.info,  Node: Installation,  Next: Adding notes,  Prev: Introduction,  Up: Top
+
+2 Installation
+**************
+
+Gnosis is not currently available in any ELPA, the recommended way to
+install gnosis is via straight.el:
+
+   <https://github.com/radian-software/straight.el>
+
+* Menu:
+
+* Using straight.el: Using straightel.
+* Installing manually from source::
+
+
+File: gnosis.info,  Node: Using straightel,  Next: Installing manually from source,  Up: Installation
+
+2.1 Using straight.el
+=====================
+
+If you have not installed straight.el, follow the instructions here:
+
+   <https://github.com/radian-software/straight.el>
+
+   Once you have installed straight.el, you can install gnosis using the
+following emacs lisp snippet:
+
+     (straight-use-package
+      '(gnosis :type git
+               :host nil
+               :repo "https://git.thanosapollo.org/gnosis"))
+
+
+File: gnosis.info,  Node: Installing manually from source,  Prev: Using straightel,  Up: Installation
+
+2.2 Installing manually from source
+===================================
+
+Gnosis depends on the ‘compat’ & ‘emacsql’ libraries which are available
+from MELPA.  Install them using ‘M-x package-install RET <package> RET’
+or you may also install them manually from their repository.
+
+   • Clone gnosis repository
+
+          $ git clone https://git.thanosapollo.org/gnosis ~/.emacs.d/site-lisp/gnosis
+
+   • Add this to your emacs configuration
+
+          (add-to-list 'load-path "~/.emacs.d/site-lisp/gnosis")
+          (load-file "~/.emacs.d/site-lisp/gnosis/gnosis.el")
+
+
+File: gnosis.info,  Node: Adding notes,  Next: Note Types,  Prev: Installation,  Up: Top
+
+3 Adding notes
+**************
+
+Creating notes for gnosis can be done interactively with: ‘M-x
+gnosis-add-note’
+
+   Advanced/Power users may prefer to use ‘gnosis-add-note--TYPE’
+
+   Example:
+
+     (gnosis-add-note--basic :deck "DECK-NAME"
+                             :question "Your Question"
+                             :answer "Answer"
+                             :hint "hint"
+                             :extra "Explanation"
+                             :image "Image displayed before user-input" ;; Optional
+                             :second-image "Image displayed after user-input" ;; Optional
+                             :tags '("tag1" "tag2"))
+
+   By default, the value of image and second image is nil.  Their value
+must a string, the path of an image, from inside ‘gnosis-images-dir’.
+
+   Each note type has a ‘gnosis-add-note-TYPE’ that is used
+interactively & a "hidden function" ‘gnosis-add-note--TYPE’ that handles
+all the logic.
+
+   Every note type has these values in common:
+
+   • ‘extra’ string value, extra information/explanation displayed after
+     user-input
+   • ‘image’ Image displayed _before_ user input
+   • ‘second-image’ Image displayed _after_ user input
+
+   The following sections will cover the important differences you have
+to know when creating notes.
+
+
+File: gnosis.info,  Node: Note Types,  Next: Customization,  Prev: Adding notes,  Up: Top
+
+4 Note Types
+************
+
+* Menu:
+
+* Cloze::
+* Basic Type::
+* Double::
+* MCQ (Multiple Choice Question)::
+* y-or-n::
+
+
+File: gnosis.info,  Node: Cloze,  Next: Basic Type,  Up: Note Types
+
+4.1 Cloze
+=========
+
+A cloze note type is a format where you create sentences or paragraphs
+with "missing" words.  Almost all note types can be written as a cloze
+type in a way.  Ideal type for memorizing definitions.
+
+   To get the most out of gnosis, you have to become familiar with cloze
+type notes.
+
+   You can create a cloze note type using ‘M-x gnosis-add-note’ and
+selecting ‘Cloze’, the question should be formatted like this:
+
+     {c1:Cyproheptadine} is a(n) {c2:5-HT2} receptor antagonist used to
+     treat {c2:serotonin syndrome}
+
+   You can also format clozes like Anki if you prefer; e.g
+‘{{c1::Cyproheptadine}}’
+
+   • For each 'cX'-tag there will be created a cloze type note, the
+     above example creates 2 cloze type notes.
+
+   • Each 'cX' tag can have multiple clozes, but each cloze must be a
+     *UNIQUE* word (or a unique combination of words) in given note.
+
+
+File: gnosis.info,  Node: Basic Type,  Next: Double,  Prev: Cloze,  Up: Note Types
+
+4.2 Basic Type
+==============
+
+Basic note type is a simple question/answer note, where the user first
+sees a "main" part, which is usually a question, and he is prompted to
+input the answer.
+
+
+File: gnosis.info,  Node: Double,  Next: MCQ (Multiple Choice Question),  Prev: Basic Type,  Up: Note Types
+
+4.3 Double
+==========
+
+Double note type, is essentially a note that generates 2 basic notes.
+The second one reverses question/answer.
+
+   Ideal for vocabulary acquisition, creating vocabulary/translation
+notes for a foreign language.
+
+
+File: gnosis.info,  Node: MCQ (Multiple Choice Question),  Next: y-or-n,  Prev: Double,  Up: Note Types
+
+4.4 MCQ (Multiple Choice Question)
+==================================
+
+MCQ note type, consists of a "stem" part that is displayed, and
+"options" for the user to select the right one.
+
+   Answer must be the index NUMBER of the correct answer from OPTIONS.
+
+   Ideal for self testing & simulating exams
+
+
+File: gnosis.info,  Node: y-or-n,  Prev: MCQ (Multiple Choice Question),  Up: Note Types
+
+4.5 y-or-n
+==========
+
+y-or-n (yes or no) note type, user is presented with a question and
+prompted to enter character "y" or "n".
+
+   When using the hidden function ‘gnosis-add-note--y-or-n’, note that
+the ANSWER must be either 121 (‘y’) or 110 (‘n’), as those correspond to
+the character values used to represent them.
+
+
+File: gnosis.info,  Node: Customization,  Prev: Note Types,  Up: Top
+
+5 Customization
+***************
+
+* Menu:
+
+* Gnosis Algorithm Initial Interval::
+* Gnosis Algorithm Easiness Factor::
+* Gnosis Algorithm Forgetting Factor::
+
+
+File: gnosis.info,  Node: Gnosis Algorithm Initial Interval,  Next: Gnosis Algorithm Easiness Factor,  Up: Customization
+
+5.1 Gnosis Algorithm Initial Interval
+=====================================
+
+‘gnosis-algorithm-interval’ is a list of 2 numbers, representing the
+first two initial intervals for successful reviews.
+
+   Example:
+
+     (setq gnosis-algorithm-interval '(1 3))
+
+   Using the above example, after first successfully reviewing a note,
+you will see it again tomorrow, if you successfully review said note
+again, the next review will be after 3 days.
+
+
+File: gnosis.info,  Node: Gnosis Algorithm Easiness Factor,  Next: Gnosis Algorithm Forgetting Factor,  Prev: Gnosis Algorithm Initial Interval,  Up: Customization
+
+5.2 Gnosis Algorithm Easiness Factor
+====================================
+
+‘gnosis-algorithm-ef’ is a list that consists of 3 items.
+
+   The first item is the increase factor, used to increase the easiness
+factor upon successful review.
+
+   Second item refers to the decrease factor, used to decrease the
+easiness factor upon an unsuccessful review.
+
+   The third item is the initial total easiness factor, used to
+calculate the next interval.
+
+   The basic's of how this is used is that it's being multiplied with
+the last interval upon a successful review, e.g if you last reviewed a
+note 6 days ago, and the easiness factor of this note is 2.0, your next
+interval would be 6 * 2.0 & the total easiness factor would be 2.0 +
+increase-factor as well.
+
+   Example:
+
+     (setq gnosis-algorithm-ef '(0.3 0.3 1.3))
+
+
+File: gnosis.info,  Node: Gnosis Algorithm Forgetting Factor,  Prev: Gnosis Algorithm Easiness Factor,  Up: Customization
+
+5.3 Gnosis Algorithm Forgetting Factor
+======================================
+
+‘gnosis-algorithm-ff’ is a floating number below 1.
+
+   It's used to calculate the next interval upon an unsuccessful review,
+by being multiplied with last interval.
+
+   Example:
+
+     (setq gnosis-algorithm-ff 0.5)
+
+   For a note with a value of last-interval of 6 days and a ff of 0.5,
+upon an unsuccessful review the next interval will be 6 * 0.5
+
+
+
+Tag Table:
+Node: Top246
+Node: Introduction1249
+Node: Installation1729
+Node: Using straightel2098
+Node: Installing manually from source2614
+Node: Adding notes3303
+Node: Note Types4729
+Node: Cloze4941
+Node: Basic Type5914
+Node: Double6192
+Node: MCQ (Multiple Choice Question)6538
+Node: y-or-n6947
+Node: Customization7373
+Node: Gnosis Algorithm Initial Interval7602
+Node: Gnosis Algorithm Easiness Factor8174
+Node: Gnosis Algorithm Forgetting Factor9159
+
+End Tag Table
+
+
+Local Variables:
+coding: utf-8
+End:
diff --git a/doc/gnosis.org b/doc/gnosis.org
new file mode 100644
index 0000000..8d23a30
--- /dev/null
+++ b/doc/gnosis.org
@@ -0,0 +1,235 @@
+#+TITLE: Gnosis User Manual
+#+AUTHOR: Thanos Apollo
+#+email: [email protected]
+#+language: en
+#+options: ':t toc:nil author:t email:t num:t
+#+startup: content
+#+macro: stable-version 0.1.3
+#+macro: release-date 2023-01-18
+#+macro: development-version 0.1.4-dev
+#+macro: file @@texinfo:@file{@@$1@@texinfo:}@@
+#+macro: space @@texinfo:@: @@
+#+macro: kbd @@texinfo:@kbd{@@$1@@texinfo:}@@
+#+macro: file @@texinfo:@file{@@$1@@texinfo:}@@
+#+macro: space @@texinfo:@: @@
+#+macro: kbd @@texinfo:@kbd{@@$1@@texinfo:}@@
+#+texinfo_filename: gnosis.info
+#+texinfo_dir_category: Emacs misc features
+#+texinfo_dir_title: Gnosis (γνῶσις): (gnosis) 
+#+texinfo_dir_desc: Spaced Repetition System For Note Taking And Self-Testing
+#+texinfo_header: @set MAINTAINERSITE @uref{https://thanosapollo.org,maintainer webpage}
+#+texinfo_header: @set MAINTAINER Thanos Apollo
+#+texinfo_header: @set MAINTAINEREMAIL @email{[email protected]}
+#+texinfo_header: @set MAINTAINERCONTACT @uref{mailto:[email protected],contact the maintainer}
+
+
+Gnosis (γνῶσις), pronounced "noh-sis", /meaning knowledge in Greek/, is
+a spaced repetition system implementation for note taking and self
+testing.
+
+#+texinfo: @noindent
+This manual is written for Gnosis version {{{stable-version}}}, released on {{{release-date}}}.
+
++ Official manual: <https://thanosapollo.org/user-manual/gnosis>
++ Git repositories:
+  + main:               <https://git.thanosapollo.org/gnosis>
+  + sourcehut (mirror): <https://git.sr.ht/~thanosapollo/gnosis>
+
+#+texinfo: @insertcopying
+
+* Introduction
+Gnosis is a spaced repetition note taking and self testing system,
+where notes are taken in a Question/Answer/Explanation-like format &
+reviewed in spaced intervals.
+
+Gnosis can help you better understand and retain the material by
+encouraging active engagement. It also provides a clear structure for
+your notes & review sessions, making it easier to study.
+
+* Installation
+
+Gnosis is not currently available in any ELPA, the recommended way to
+install gnosis is via straight.el:
+
+   <https://github.com/radian-software/straight.el>
+  
+** Using straight.el
+If you have not installed straight.el, follow the instructions here:
+
+   <https://github.com/radian-software/straight.el>
+
+Once you have installed straight.el, you can install gnosis using the
+following emacs lisp snippet:
+
+#+begin_src emacs-lisp
+  (straight-use-package 
+   '(gnosis :type git
+  	  :host nil
+  	  :repo "https://git.thanosapollo.org/gnosis"))
+#+end_src
+
+** Installing manually from source
+Gnosis depends on the ~compat~ & ~emacsql~ libraries which are available
+from MELPA. Install them using ~M-x package-install RET <package> RET~
+or you may also install them manually from their repository.
+
++ Clone gnosis repository
+  
+  #+begin_src shell
+    $ git clone https://git.thanosapollo.org/gnosis ~/.emacs.d/site-lisp/gnosis
+  #+end_src
+
++ Add this to your emacs configuration
+  
+  #+begin_src emacs-lisp
+    (add-to-list 'load-path "~/.emacs.d/site-lisp/gnosis")
+    (load-file "~/.emacs.d/site-lisp/gnosis/gnosis.el")
+  #+end_src
+
+* Adding notes
+Creating notes for gnosis can be done interactively with:
+  =M-x gnosis-add-note=
+
+
+Advanced/Power users may prefer to use =gnosis-add-note--TYPE=
+
+Example: 
+
+#+begin_src emacs-lisp
+  (gnosis-add-note--basic :deck "DECK-NAME"
+  			:question "Your Question"
+  			:answer "Answer"
+  			:hint "hint"
+  			:extra "Explanation"
+  			:image "Image displayed before user-input" ;; Optional
+  			:second-image "Image displayed after user-input" ;; Optional
+  			:tags '("tag1" "tag2"))
+#+end_src
+
+By default, the value of image and second image is nil. Their value
+must a string, the path of an image, from inside ~gnosis-images-dir~.
+
+Each note type has a =gnosis-add-note-TYPE= that is used
+interactively & a "hidden function" =gnosis-add-note--TYPE= that handles
+all the logic.
+
+Every note type has these values in common:
+
+ + ~extra~ string value, extra information/explanation displayed after user-input
+ + ~image~ Image displayed /before/ user input
+ + ~second-image~ Image displayed /after/ user input
+
+The following sections will cover the important differences you have
+to know when creating notes.  
+
+* Note Types
+** Cloze
+
+A cloze note type is a format where you create sentences or paragraphs
+with "missing" words. Almost all note types can be written as a cloze
+type in a way. Ideal type for memorizing definitions.
+
+To get the most out of gnosis, you have to become familiar with cloze type notes.
+
+You can create a cloze note type using =M-x gnosis-add-note= and
+selecting ~Cloze~, the question should be formatted like this:
+
+#+BEGIN_QUOTE
+{c1:Cyproheptadine} is a(n) {c2:5-HT2} receptor antagonist used to treat {c2:serotonin syndrome}
+#+END_QUOTE
+
+You can also format clozes like Anki if you prefer; e.g ~{{c1::Cyproheptadine}}~
+
++ For each `cX`-tag there will be created a cloze type note, the above
+  example creates 2 cloze type notes.
+  
++ Each `cX` tag can have multiple clozes, but each cloze must be a
+  *UNIQUE* word (or a unique combination of words) in given note.
+
+** Basic Type
+
+Basic note type is a simple question/answer note, where the user first
+sees a "main" part, which is usually a question, and he is prompted to
+input the answer. 
+
+** Double
+Double note type, is essentially a note that generates 2 basic notes.
+The second one reverses question/answer.
+
+Ideal for vocabulary acquisition, creating vocabulary/translation
+notes for a foreign language.
+
+** MCQ (Multiple Choice Question)
+MCQ note type, consists of a "stem" part that is displayed, and
+"options" for the user to select the right one.
+
+Answer must be the index NUMBER of the correct answer from OPTIONS.
+
+Ideal for self testing & simulating exams
+
+** y-or-n
+y-or-n (yes or no) note type, user is presented with a question and
+prompted to enter character "y" or "n".
+
+When using the hidden function =gnosis-add-note--y-or-n=, note that the
+ANSWER must be either 121 (~y~) or 110 (~n~), as those correspond to the
+character values used to represent them.
+
+* Customization
+** Gnosis Algorithm Initial Interval
+
+=gnosis-algorithm-interval= is a list of 2 numbers, representing the
+first two initial intervals for successful reviews.
+
+Example:
+
+#+begin_src emacs-lisp
+  (setq gnosis-algorithm-interval '(1 3))
+#+end_src
+
+Using the above example, after first successfully reviewing a note,
+you will see it again tomorrow, if you successfully review said note
+again, the next review will be after 3 days.
+
+** Gnosis Algorithm Easiness Factor
+
+=gnosis-algorithm-ef= is a list that consists of 3 items.
+
+The first item is the increase factor, used to increase the easiness
+factor upon successful review.
+
+Second item refers to the decrease factor, used to
+decrease the easiness factor upon an unsuccessful review.
+
+The third item is the initial total easiness factor, used to calculate
+the next interval.
+
+The basic's of how this is used is that it's being multiplied with the
+last interval upon a successful review, e.g if you last reviewed a
+note 6 days ago, and the easiness factor of this note is 2.0, your
+next interval would be 6 * 2.0 & the total easiness factor would be
+2.0 + increase-factor as well.
+
+Example:
+
+#+begin_src emacs-lisp
+  (setq gnosis-algorithm-ef '(0.3 0.3 1.3))
+#+end_src
+
+** Gnosis Algorithm Forgetting Factor
+
+=gnosis-algorithm-ff= is a floating number below 1.
+
+It's used to calculate the next interval upon an unsuccessful review,
+by being multiplied with last interval.
+
+
+
+Example:
+
+#+begin_src emacs-lisp
+  (setq gnosis-algorithm-ff 0.5)
+#+end_src
+
+For a note with a value of last-interval of 6 days and a ff of 0.5,
+upon an unsuccessful review the next interval will be 6 * 0.5
diff --git a/doc/gnosis.texi b/doc/gnosis.texi
new file mode 100644
index 0000000..58c7f4e
--- /dev/null
+++ b/doc/gnosis.texi
@@ -0,0 +1,324 @@
+\input texinfo    @c -*- texinfo -*-
+@c %**start of header
+@setfilename gnosis.info
+@settitle Gnosis User Manual
+@documentencoding UTF-8
+@documentlanguage en
+@set MAINTAINERSITE @uref{https://thanosapollo.org,maintainer webpage}
+@set MAINTAINER Thanos Apollo
+@set MAINTAINEREMAIL @email{[email protected]}
+@set MAINTAINERCONTACT @uref{mailto:[email protected],contact the maintainer}
+@c %**end of header
+
+@dircategory Emacs misc features
+@direntry
+* Gnosis (γνῶσις): (gnosis). Spaced Repetition System For Note Taking And Self-Testing.
+@end direntry
+
+@finalout
+@titlepage
+@title Gnosis User Manual
+@author Thanos Apollo (@email{public@@thanosapollo.org})
+@end titlepage
+
+@ifnottex
+@node Top
+@top Gnosis User Manual
+
+Gnosis (γνῶσις), pronounced ``noh-sis'', @emph{meaning knowledge in Greek}, is
+a spaced repetition system implementation for note taking and self
+testing.
+
+@noindent
+This manual is written for Gnosis version 0.1.3, released on 2023-01-18.
+
+@itemize
+@item
+Official manual: @uref{https://thanosapollo.org/user-manual/gnosis}
+@item
+Git repositories:
+@itemize
+@item
+main:               @uref{https://git.thanosapollo.org/gnosis}
+@item
+sourcehut (mirror): @uref{https://git.sr.ht/~thanosapollo/gnosis}
+@end itemize
+@end itemize
+
+@insertcopying
+
+@end ifnottex
+
+@menu
+* Introduction::
+* Installation::
+* Adding notes::
+* Note Types::
+* Customization::
+
+@detailmenu
+--- The Detailed Node Listing ---
+
+Installation
+
+* Using straight.el: Using straightel. 
+* Installing manually from source::
+
+Note Types
+
+* Cloze::
+* Basic Type::
+* Double::
+* MCQ (Multiple Choice Question)::
+* y-or-n::
+
+Customization
+
+* Gnosis Algorithm Initial Interval::
+* Gnosis Algorithm Easiness Factor::
+* Gnosis Algorithm Forgetting Factor::
+
+@end detailmenu
+@end menu
+
+@node Introduction
+@chapter Introduction
+
+Gnosis is a spaced repetition note taking and self testing system,
+where notes are taken in a Question/Answer/Explanation-like format &
+reviewed in spaced intervals.
+
+Gnosis can help you better understand and retain the material by
+encouraging active engagement. It also provides a clear structure for
+your notes & review sessions, making it easier to study.
+
+@node Installation
+@chapter Installation
+
+Gnosis is not currently available in any ELPA, the recommended way to
+install gnosis is via straight.el:
+
+@uref{https://github.com/radian-software/straight.el}
+
+@menu
+* Using straight.el: Using straightel. 
+* Installing manually from source::
+@end menu
+
+@node Using straightel
+@section Using straight.el
+
+If you have not installed straight.el, follow the instructions here:
+
+@uref{https://github.com/radian-software/straight.el}
+
+Once you have installed straight.el, you can install gnosis using the
+following emacs lisp snippet:
+
+@lisp
+(straight-use-package 
+ '(gnosis :type git
+          :host nil
+          :repo "https://git.thanosapollo.org/gnosis"))
+@end lisp
+
+@node Installing manually from source
+@section Installing manually from source
+
+Gnosis depends on the @code{compat} & @code{emacsql} libraries which are available
+from MELPA@. Install them using @code{M-x package-install RET <package> RET}
+or you may also install them manually from their repository.
+
+@itemize
+@item
+Clone gnosis repository
+
+@example
+$ git clone https://git.thanosapollo.org/gnosis ~/.emacs.d/site-lisp/gnosis
+@end example
+
+@item
+Add this to your emacs configuration
+
+@lisp
+(add-to-list 'load-path "~/.emacs.d/site-lisp/gnosis")
+(load-file "~/.emacs.d/site-lisp/gnosis/gnosis.el")
+@end lisp
+@end itemize
+
+@node Adding notes
+@chapter Adding notes
+
+Creating notes for gnosis can be done interactively with:
+  @samp{M-x gnosis-add-note}
+
+
+Advanced/Power users may prefer to use @samp{gnosis-add-note--TYPE}
+
+Example: 
+
+@lisp
+(gnosis-add-note--basic :deck "DECK-NAME"
+                        :question "Your Question"
+                        :answer "Answer"
+                        :hint "hint"
+                        :extra "Explanation"
+                        :image "Image displayed before user-input" ;; Optional
+                        :second-image "Image displayed after user-input" ;; Optional
+                        :tags '("tag1" "tag2"))
+@end lisp
+
+By default, the value of image and second image is nil. Their value
+must a string, the path of an image, from inside @code{gnosis-images-dir}.
+
+Each note type has a @samp{gnosis-add-note-TYPE} that is used
+interactively & a ``hidden function'' @samp{gnosis-add-note--TYPE} that handles
+all the logic.
+
+Every note type has these values in common:
+
+@itemize
+@item
+@code{extra} string value, extra information/explanation displayed after user-input
+@item
+@code{image} Image displayed @emph{before} user input
+@item
+@code{second-image} Image displayed @emph{after} user input
+@end itemize
+
+The following sections will cover the important differences you have
+to know when creating notes.
+
+@node Note Types
+@chapter Note Types
+
+@node Cloze
+@section Cloze
+
+A cloze note type is a format where you create sentences or paragraphs
+with ``missing'' words. Almost all note types can be written as a cloze
+type in a way. Ideal type for memorizing definitions.
+
+To get the most out of gnosis, you have to become familiar with cloze type notes.
+
+You can create a cloze note type using @samp{M-x gnosis-add-note} and
+selecting @code{Cloze}, the question should be formatted like this:
+
+@quotation
+@{c1:Cyproheptadine@} is a(n) @{c2:5-HT2@} receptor antagonist used to treat @{c2:serotonin syndrome@}
+
+@end quotation
+
+You can also format clozes like Anki if you prefer; e.g @code{@{@{c1::Cyproheptadine@}@}}
+
+@itemize
+@item
+For each `cX`-tag there will be created a cloze type note, the above
+example creates 2 cloze type notes.
+
+@item
+Each `cX` tag can have multiple clozes, but each cloze must be a
+@strong{UNIQUE} word (or a unique combination of words) in given note.
+@end itemize
+
+@node Basic Type
+@section Basic Type
+
+Basic note type is a simple question/answer note, where the user first
+sees a ``main'' part, which is usually a question, and he is prompted to
+input the answer.
+
+@node Double
+@section Double
+
+Double note type, is essentially a note that generates 2 basic notes.
+The second one reverses question/answer.
+
+Ideal for vocabulary acquisition, creating vocabulary/translation
+notes for a foreign language.
+
+@node MCQ (Multiple Choice Question)
+@section MCQ (Multiple Choice Question)
+
+MCQ note type, consists of a ``stem'' part that is displayed, and
+``options'' for the user to select the right one.
+
+Answer must be the index NUMBER of the correct answer from OPTIONS@.
+
+Ideal for self testing & simulating exams
+
+@node y-or-n
+@section y-or-n
+
+y-or-n (yes or no) note type, user is presented with a question and
+prompted to enter character ``y'' or ``n''.
+
+When using the hidden function @samp{gnosis-add-note--y-or-n}, note that the
+ANSWER must be either 121 (@code{y}) or 110 (@code{n}), as those correspond to the
+character values used to represent them.
+
+@node Customization
+@chapter Customization
+
+@node Gnosis Algorithm Initial Interval
+@section Gnosis Algorithm Initial Interval
+
+@samp{gnosis-algorithm-interval} is a list of 2 numbers, representing the
+first two initial intervals for successful reviews.
+
+Example:
+
+@lisp
+(setq gnosis-algorithm-interval '(1 3))
+@end lisp
+
+Using the above example, after first successfully reviewing a note,
+you will see it again tomorrow, if you successfully review said note
+again, the next review will be after 3 days.
+
+@node Gnosis Algorithm Easiness Factor
+@section Gnosis Algorithm Easiness Factor
+
+@samp{gnosis-algorithm-ef} is a list that consists of 3 items.
+
+The first item is the increase factor, used to increase the easiness
+factor upon successful review.
+
+Second item refers to the decrease factor, used to
+decrease the easiness factor upon an unsuccessful review.
+
+The third item is the initial total easiness factor, used to calculate
+the next interval.
+
+The basic's of how this is used is that it's being multiplied with the
+last interval upon a successful review, e.g if you last reviewed a
+note 6 days ago, and the easiness factor of this note is 2.0, your
+next interval would be 6 * 2.0 & the total easiness factor would be
+2.0 + increase-factor as well.
+
+Example:
+
+@lisp
+(setq gnosis-algorithm-ef '(0.3 0.3 1.3))
+@end lisp
+
+@node Gnosis Algorithm Forgetting Factor
+@section Gnosis Algorithm Forgetting Factor
+
+@samp{gnosis-algorithm-ff} is a floating number below 1.
+
+It's used to calculate the next interval upon an unsuccessful review,
+by being multiplied with last interval.
+
+
+
+Example:
+
+@lisp
+(setq gnosis-algorithm-ff 0.5)
+@end lisp
+
+For a note with a value of last-interval of 6 days and a ff of 0.5,
+upon an unsuccessful review the next interval will be 6 * 0.5
+
+@bye