“Universal” Widgets

Introduction

Short Text Widget

Type:

:: String

Value:

• single-line text.

Behavior:

• Press <ret> to submit.

HTML:

<input type="">Name: <input/>

Emacs:

(read-string "Name :")

CLI (Prompting):

#!/bin/sh

printf "Name: "
read NAME


LENGTH=$(printf "%s\n" ${NAME} | wc -m)
printf "Name Length: %d\n" ${LENGTH}

# POSIX-conformant

Examples:

• —

Links:

• <>
• <>

Type:

:: [String]

Value:

• multi-line text.

Behavior:

• Full Editing — <ret> is newline (i.e. doesn’t submit): for HTML, by default, click a “Submit” <button>; for Emacs, by default, press C-c C-c; with a custom widget, press <ret> twice; with a custom widget, press <S-ret>.

HTML:

<textarea><textarea/>

Emacs:

(read-buffer? "Text :")

CLI (Completion):

$ 

Examples:

• magit.el — edit the git commit message.

Links:

• <>
• <>

i.e. Password Input.

Type:

:: String

Value:

• text which is secret.

Behavior:

• MUST NOT echo input
• May echo input length (e.g. print a * for each character entered).
• Press <ret> to submit.

HTML:

<input type="password">Password: <input/>

Emacs:

(read-passwors "Password :") TODO

CLI (Prompting):

#!/bin/sh

stty -echo
printf "Password: "
read PASSWORD
stty echo

LENGTH=$(printf "%s\n" ${PASSWORD} | wc -m)
printf "Password Length: %d\n" ${LENGTH}

# POSIX-conformant

Examples:

• —

Links:

• <>
• <>

i.e. a Checklist.

Type:

:: (Enum a) => Set a

Value:

Behavior:

HTML:

<>
  <input type="checkbox">A<input/>
  <input type="checkbox">A<input/>
</>

Emacs (Minibuffer):

(TODO)

Emacs (Widget):

(widget-create)

Examples:

• —

Links:

• <>
• <>

i.e. a Radio-Group.

Type:

:: (Enum a) => a

Value:

• one choice, from a set of choices

Behavior:

• Press a single key.
• Click a single button.

HTML:

<input type="radio">

  < label="Google Chrome">
  <option value="Firefox">
  <option value="Internet Explorer">
  <option value="Opera">
  <option value="Safari">
  <option value="Microsoft Edge">

Emacs:

(read-choice-

CLI (Prompting):

$ read-char TODO

Examples:

• —

Links:

• <>

i.e. a “Finite-List”.

Type:

:: (Enum a) => a

Value:

• one choice, from a set of choices

Behavior:

• Completion (possibly)
• Defaulting (possibly)
• Vertical Navigation (possibly)

HTML:

<!-- the chooser: -->

<label for="myBrowser">Choose a browser from this list:</label>
<input list="browsers" id="myBrowser" name="myBrowser" />


<!-- the choices: -->

<datalist id="browsers">

  <option value="Google Chrome">
  <option value="Firefox">
  <option value="Internet Explorer">
  <option value="Opera">
  <option value="Safari">
  <option value="Microsoft Edge">


</datalist>

Emacs:

(let ((CHOICES '(
  "Google Chrome"
  "Firefox"
  "Internet Explorer"
  "Opera"
  "Safari"
  "Microsoft Edge"
  )))

 (completing-read "Browser: " CHOICES))

CLI (Completion):

$ IFS="\n" compgen ... -W <<<EOF
  "Google Chrome"
  "Firefox"
  "Internet Explorer"
  "Opera"
  "Safari"
  "Microsoft Edge"
EOF

Representation (must match):

data Browser

  = Firefox
  | GoogleChrome
  | InternetExplorer
  | Opera
  | Safari
  | MicrosoftEdge

  deriving ( Enum, Bounded, ... )

Representation (free text):

type Browser = Either UnknownBrowser KnownBrowser

--

data KnownBrowser

  = Firefox
  | GoogleChrome
  | InternetExplorer
  | Opera
  | Safari
  | MicrosoftEdge

  deriving ( Enum, Bounded, ... )

--

newtype UnknownBrowser = UnknownBrowser String

  deriving ( IsString, ... )

Examples:

• —

Links:

• <>
• https://www.gnu.org/software/emacs/manual/html_node/elisp/Minibuffer-Completion.html

i.e. a File-Chooser.

Type:

:: FilePath

Value:

• one filepath, from a set of choices.
• regular-only (possibly) or "directory-only*(possibly).
• must-exist (possibly) or can’t-exist (possibly).

Behavior:

• Vertical Navigation (possibly) between the directory contents
• Horizontal Navigation (possibly) between returning to the parent directory or descending into subdirectories.

HTML:

read-file-name (Emacs): (read-file-name PROMPT &optional DIR DEFAULT-FILENAME MUSTMATCH INITIAL PREDICATE)(a.k.a C-x C-f)

(read-file-name "Open File: " default-directory nil t)

(read-file-name "Open Directory: " )

(read-file-name "New File: " )

(defun sboo-elisp-filename-p (filename)
  (match filename (rx ".el" eos))) ;TODO

  (read-file-name "Open File: " default-directory nil nil nil #'sboo-elisp-filename-p))

CLI (Completion):

$ compgen ... -A file

$ compgen ... -A directory

Examples:

• —

Links:

• <>
• <>