Marpa Enhanced Calculator

(Example for my Marpa presentation)

My other Marpa-related answers on forums:

• Disallow keywords as identifiers
• Key-value format
• Lisp-like parentheses
• Parsing a JSON-like format
• Key-value pairs with optionally quoted values
• Strange XML/JSON like format with multiline attributes
• Using "depth" in the derivation tree
• Split on unquoted space
• Converting a Context Free Grammar to BNF
• Masking Data in a MySQL Dump File
• Serialize a Tree Structured Config
• Boolean Expression Parser
• Config with Arrays
• Arbitrary Boolean Expressions
• Parsing bracket formatted file
• Parsing Emacs Lisp sexpr
• Parsing nested angle brackets

And the most advanced example so far, the parser of the Karel language:

• Karel::Parser