Strictly for Ruby. Not really included: Handwritten lexer/parser.

Lexers:

• Rex/Rexical
• Ragel
• piotrmurach/lex
• Handwritten (e.g. with StringScanner)
• re2c with bindings to Ruby

Parsers requiring lexer:

• Racc
• Yacc/Byacc/Bison/Lemon with bindings to Ruby

PEG:

• Treetop
• Parslet
• kpeg
• citrus
• peg/leg with bindings to Ruby
• Canopy
• Waxeye

Parser combinators:

• D★Parse — ends up being super slow because of super-linear performance.
• Parsby

All-in-one solutions:

• RLTK

Articles

• Parser Combinators in Ruby
• Introduction to parser combinators
• Building a Programming Language in Ruby: The Parser
• Calculator Tutorial Part 1: Basic lexer