WIP

.ruby-version

@@ -1 +1 @@
-2.6.3
+2.7.0

Gemfile.lock

@@ -1,48 +1,51 @@
 PATH
   remote: .
   specs:
-    feeble (0.1.0)
+    feeble (0.2.0)
+      immutable-ruby
       zeitwerk
 
 GEM
   remote: https://rubygems.org/
   specs:
-    byebug (11.0.1)
+    byebug (11.1.1)
     coderay (1.1.2)
+    concurrent-ruby (1.0.5)
     diff-lcs (1.3)
+    immutable-ruby (0.0.4)
+      concurrent-ruby (~> 1.0.0)
     method_source (0.9.2)
     pry (0.12.2)
       coderay (~> 1.1.0)
       method_source (~> 0.9.0)
-    pry-byebug (3.7.0)
+    pry-byebug (3.8.0)
       byebug (~> 11.0)
       pry (~> 0.10)
-    rake (10.5.0)
-    rspec (3.8.0)
-      rspec-core (~> 3.8.0)
-      rspec-expectations (~> 3.8.0)
-      rspec-mocks (~> 3.8.0)
-    rspec-core (3.8.0)
-      rspec-support (~> 3.8.0)
-    rspec-expectations (3.8.3)
+    rake (13.0.1)
+    rspec (3.9.0)
+      rspec-core (~> 3.9.0)
+      rspec-expectations (~> 3.9.0)
+      rspec-mocks (~> 3.9.0)
+    rspec-core (3.9.1)
+      rspec-support (~> 3.9.1)
+    rspec-expectations (3.9.0)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.8.0)
-    rspec-mocks (3.8.0)
+      rspec-support (~> 3.9.0)
+    rspec-mocks (3.9.1)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.8.0)
-    rspec-support (3.8.0)
-    zeitwerk (2.1.6)
+      rspec-support (~> 3.9.0)
+    rspec-support (3.9.2)
+    zeitwerk (2.2.2)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
   bundler (~> 2.0)
   feeble!
-  pry
-  pry-byebug
-  rake (~> 10.0)
-  rspec (~> 3.0)
+  pry-byebug (~> 3)
+  rake (~> 13.0)
+  rspec
 
 BUNDLED WITH
-   2.0.1
+   2.1.2

README.md

@@ -1,8 +1,8 @@
 # Feeble
 
-Welcome to your new gem! In this directory, you'll find the files you need to be able to package up your Ruby library into a gem. Put your Ruby code in the file `lib/feeble`. To experiment with that code, run `bin/console` for an interactive prompt.
-
-TODO: Delete this and the text above, and describe your gem
+A small programming language for education purposes.
+It is functional, favoring immuatbility and supports TCO.
+Meant to be hosted, uses Ruby as a "runtime".
 
 ## Installation
 

bin/console

@@ -10,8 +10,5 @@ require "feeble"
 require "pry"
 
 include Feeble
-include Feeble::Reader
-include Feeble::Evaler
-include Feeble::Runtime
 
 Pry.start

feeble.gemspec

@@ -27,10 +27,10 @@ Gem::Specification.new do |spec|
   spec.require_paths = ["lib"]
 
   spec.add_development_dependency "bundler", "~> 2.0"
-  spec.add_development_dependency "rake", "~> 10.0"
-  spec.add_development_dependency "rspec", "~> 3.0"
-  spec.add_development_dependency "pry"
-  spec.add_development_dependency "pry-byebug"
+  spec.add_development_dependency "rake", "~> 13.0"
+  spec.add_development_dependency "rspec"
+  spec.add_development_dependency "pry-byebug", "~>3"
 
   spec.add_dependency "zeitwerk"
+  spec.add_dependency "immutable-ruby"
 end

lib/feeble/pushback_reader.rb

@@ -0,0 +1,48 @@
+class Feeble::PushbackReader
+  def self.with(io, chunk_size: 16384)
+    raise "Pass the block that will receive the pushback reader" if !block_given?
+
+    reader = new(io, chunk_size: chunk_size)
+    yield(reader)
+    reader.close
+  end
+
+  def initialize(io, chunk_size: 16384)
+    @io = io.is_a?(String) ? StringIO.new(io) : io
+    @chunk_size = chunk_size
+    @started = nil
+    @buffer = []
+  end
+
+  def next
+    return nil if eof?
+
+    @started ||= true
+    bufferize if @buffer.length == 0
+    @buffer.shift
+  end
+
+  def peek(length = 1)
+    bufferize if !@started
+    str = @buffer[0...length]
+    str.length > 0 ? str.join : nil
+  end
+
+  def push(string)
+    @buffer = string.to_s.chars + @buffer
+  end
+
+  def eof?
+    @buffer.length == 0 && @io.eof?
+  end
+
+  def close
+    @io.close
+  end
+
+  private
+
+  def bufferize
+    @buffer = @io.read(@chunk_size).chars
+  end
+end