arythemetic_expressions_parser_Kharchenko

overview

this project implements a command-line parser for simple arithmetic expressions and handles expressions as such:

• basic arythmetics: +, -, *, /
• nested brackets: ((...))
• negative numbers: -x or expressions like -(1+2)
• special functions: log(x) for natural logarithm and sqrt(x) for square root
• basic arythemetics inside special functions (log and sqrt): log(10 + 5), sqrt(2 + 7)
• sequences of basic arythemetics: ((2 + 3) * 4)
• log is a natural logorythm (ln)

the parser evaluates input expressions and returns the result

technical description

parsing process

1. preprocessing:

   • remove outer brackets
   • handle minus at the beginning of expressions: -(...)
   • validate balanced brackets; invalid expressions get rejected

2. expression evaluation:

   • if the expression is a single number, it is returned as a result
   • if the expression contains arythmetic operators:
     • operators * and / are evaluated first
     • operators + and - are evaluated afterwards
   • brackets are recursively evaluated from inner to outer

3. special functions:

   • natural logarythm (log(x)):
     • evaluated only if x > 0, else -> error
     • returns ln(x) using f64::ln()
   • square root (sqrt(x)):
     • evaluated only if x >= 0, else -> error
     • returns sqrt(x) using f64::sqrt()

4. error handling:

   • expressions are validated for:
     • balanced brackets
     • valid numeric parsing
     • division by zero
     • domain errors for log and sqrt
     • acceptable characters (no random strings allowed)
   • invalid expressions returns ParseError::InvalidExpression

link to crates.io : https://crates.io/crates/arythemetic_expressions_parser_Kharchenko