ArithmeticParserDemo

An Arithmetic Parser Demo using Recursive Descent in Lua

Features

• Right-associative addition, subtraction, multiplication and addition.
• Left-associative exponentiation
• 'e' notation e.g 1e10
• Unary
• Parser error reporting (prints the position of the character error)

Grammar

This is in ANTLR4 format:

expr
  :   sum
  ;
  
sum
  :   prod (('+' | '-')? prod)* 
  ;
  
prod   
  :   pow (('*' | '/')? pow)*
  ;
  
pow
  :   value ('^' pow)*
  ;
  
value:  
  :   digits 
  |   ('(' expr ')')?
  ;
  
digits
  : ('-')? [0-9]* (('.')? [0-9]*)? (('e' | 'E')? [0-9]*)?
  ;