Module: Unmagic::Browser::Console::Prompt

Defined in:
lib/unmagic/browser/console/prompt.rb

Overview

An opt-in prompt that says what's open.

browser> until there's a page, and then the same green dot and title the renderer already shows for a session:

● Sign in · jobs.town> click "Email"

Off by default — the console prompts with a plain browser> . Ask for it with Unmagic::Browser::Console.start(prompt: :page).

IRB asks its context for the prompt every time it redraws the line — once per keystroke, not once per statement — so nothing here may talk to the browser. The page is read once after each statement instead, and what it said is held until the next one.

Constant Summary collapse

IDLE =

What to say when nothing's open.

"browser"
MAX_LABEL =

Long enough to tell two pages apart, short enough to leave room to type. Titles run long — "Sign in · jobs.town" is a short one.

32
SHARE =

How much of a narrow terminal the label may take before that limit comes down to meet it.

3
MIN_LABEL =

Below this there's no room for a title worth reading anyway.

12
CONTROL =

Control characters would tear the line apart — a title with a newline in it is rare, but it only has to happen once.

"\x00-\x1F"

Class Method Summary collapse

Class Method Details

.continuation(mark) ⇒ String

Lined up under render, so a multi-line statement reads as one block however long the title is.

Parameters:

  • mark (String) —

    one visible character — IRB's %l, or a *

Returns:

  • (String) 


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# File 'lib/unmagic/browser/console/prompt.rb', line 89

def continuation(mark)
  "#{" " * (@width - 2)}#{mark} "
end

.install(context) ⇒ void

This method returns an undefined value.

Give a context a prompt that follows the browser around.

IRB reads prompt_i and friends off its context every time it draws, so overriding them there is all it takes; the formats in IRB.conf stay as they are for anyone who switches prompt modes.

Parameters:

  • context (IRB::Context) 


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# File 'lib/unmagic/browser/console/prompt.rb', line 52

def install(context)
  context.define_singleton_method(:prompt_i) { Prompt.render }
  context.define_singleton_method(:prompt_s) { Prompt.continuation("%l") }
  context.define_singleton_method(:prompt_c) { Prompt.continuation("*") }

  # Any statement can have moved the page — a click that follows a
  # link says nothing about it, and neither does `js "location = ..."`
  # — so the page gets asked after every one of them rather than after
  # the verbs we could think of.
  context.define_singleton_method(:evaluate) do |*args, **options, &block|
    super(*args, **options, &block)
  ensure
    Prompt.refresh
  end

  refresh
end

.refresh ⇒ void

This method returns an undefined value.

Ask the page where it is. Everything that could raise or block happens here, so that drawing the prompt is only string work.



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# File 'lib/unmagic/browser/console/prompt.rb', line 74

def refresh
  @live, @label = read
  @width = (@live ? 2 : 0) + columns_of(@label) + 2
end

.render ⇒ String

Returns the prompt.

Returns:

  • (String) —

    the prompt



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# File 'lib/unmagic/browser/console/prompt.rb', line 80

def render
  "#{marker}#{escape(@label)}> "
end