An expression parser (small DSL) written in C - eviltoast
GitHub - torrentg/expr: An expression parser supporting multiple types
github.com
An expression parser supporting multiple types. Contribute to torrentg/expr development by creating an account on GitHub.

Key Features

  • Multiple types (number, bool, datetime, string and error)
  • Memory managed by user (no allocs)
  • Iterator based interface
  • Supporting variables
  • Stateless
  • Expressions can be compiled (RPN stack)
  • Fully compile-time checked syntax
  • Documented grammar
  • Standard C11 code
  • No dependencies

Examples

# Numerical calculations
sin((-1 + 2) * PI)

# Dates
datetrunc(now(), "day")

# Strings
"hi " + upper("bob")  + trim("  !  ")

# Conditionals
ifelse(1 < 5 && length($alphabet) > 25, "case1", "case2")

# Find the missing letter
replace($alphabet, substr($alphabet, 25 - random(0, length($alphabet)), 1), "")