EzExpr

EzExpr is a easy to use and flexible expression parser / evaluator in a one file header only style for cpp11 at least

Quick Start

ez::Expr ev;
auto result0 = ev.parse("x + 2.5 * d").set("x", 0.5).set("d", 1.5).eval().getResult();
auto result1 = ev.set("x", 10.5).eval().getResult();
auto result2 = ev.set("d", 2.5).eval().getResult();

ez::Expr ev;
ev.addFunction("fma", [](double a, double b, double c) { return a*b+c; }); // ternary function
auto result0 = ev.parse("floor(fma(x,y,k))").set("x", 0.5).set("y", 1.5).set("k", 3.2).eval().getResult();

Features

• Modern use
• One header file only
• Parsing and evaluation on separated calls
• User can easily add their custom Unary/Binary/Ternary Function
• Cpp11 compatible at least
• Can identify and return to user the variables
• Many exceptions are emited for many not conformant issue during parsing and during evaluation
• Use their own String class for faster response
• all numbers and computation are in double precision

Builtins

+ - * / ^ % 
! (factorielle : N!)

Constants

• pi
• e

Unary function

• abs, floor, ceil, round, fract, sign
• sin, cos, tan
• asin, acos, atan
• sinh, cosh, tanh
• asinh, acosh, atanh
• ln, log, log1p, logb, log2, log10
• exp
• sqrt

Binary function

• mod, atan2, min, max, step, hypot, smoothabs

Ternary function

• clamp, mis, smoothstep (glsl functions)
• saturate, lerp (hlsl functions)