Class: Fusion::CLI::Repl

Inherits:
Object
  • Object
show all
Defined in:
lib/fusion/cli/repl.rb

Constant Summary collapse

RESET = 
"\e[0m"
LIGHT_BLUE = 
"\e[94m"
GREEN = 
"\e[32m"
RED = 
"\e[31m"
PROMPT = 
"#{LIGHT_BLUE}fsn> #{RESET}"
CONTINUATION_PROMPT = 
"#{LIGHT_BLUE}...> #{RESET}"
VALUE_MARKER = 
"#{GREEN}✔ #{RESET}"
ERROR_MARKER = 
"#{RED}✗ #{RESET}"
SITE =

REPL entries report errors with the same site as inline (-e) code.

{ origin: "code", file: "<inline>" }.freeze

Instance Method Summary collapse

Constructor Details

#initialize(root_env:) ⇒ Repl

Returns a new instance of Repl.



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# File 'lib/fusion/cli/repl.rb', line 25

def initialize(root_env:)
  @root_env = root_env
end

Instance Method Details

#complete?(buffer) ⇒ Boolean

String -> yes/no

Returns:

  • (Boolean) 


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# File 'lib/fusion/cli/repl.rb', line 62

def complete?(buffer)
  return true if buffer.strip.empty?

  ast = Fusion::Parser.parse_repl(buffer, site: SITE)
  ast.is_a?(AST::Expression) || ast.is_a?(AST::Statement::Assignment)
end

#handle(buffer, environment) ⇒ Object

String (+ Env) -> String



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# File 'lib/fusion/cli/repl.rb', line 70

def handle(buffer, environment)
  ast = Fusion::Parser.parse_repl(buffer, site: SITE)
  runtime_value = CLI.evaluate(ast, environment)
  wire_pair = Serializer.serialize(runtime_value, lenient: true)
  Encoder.encode(wire_pair, mode: :bang)
end

#run ⇒ Object 



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# File 'lib/fusion/cli/repl.rb', line 29

def run
  CLI.prepare!

  require "reline"
  Reline.output = $stderr
  Reline.prompt_proc = proc do |lines|
    lines.each_index.map { |i| i.zero? ? PROMPT : CONTINUATION_PROMPT }
  end

  # The session env is a child of the run's root, so it carries the jail;
  # bindings accumulate here while loaded files stay isolated at the root.
  environment = @root_env.child.set_context(:dir, Dir.pwd)

  loop do
    buffer = begin
      Reline.readmultiline(PROMPT, true) { complete?(_1) }
    rescue Interrupt
      $stderr.puts("^C") # discard the half-typed entry and re-prompt
      next
    end

    break if buffer.nil? # Ctrl-D on an empty line ends the session
    next if buffer.strip.empty?

    output = handle(buffer, environment)

    marker = output.start_with?("!") ? ERROR_MARKER : VALUE_MARKER
    $stderr.print(marker) # decoration on stderr
    $stdout.puts(output)  # the clean value on stdout
  end
end