Macro expr 

expr!() { /* proc-macro */ }

Build a symbolic expression using natural math syntax.

All identifiers are treated as existing Rust variables of type Ex (or &Ex). They are automatically borrowed with &.

Syntax

• Operators: +, -, *, /, ^ (power)
• Functions: sin(x), cos(x), tan(x), asin(x), acos(x), atan(x), sinh(x), cosh(x), tanh(x), exp(x), ln(x), sqrt(x), abs(x)
• Parentheses for grouping
• Integer literals
• Unary minus: -x

Constants

The following identifiers are recognized as mathematical constants:

• pi, Pi, PI → π
• E → Euler’s number e
• I → imaginary unit i
• oo, inf → positive infinity

Rationals

1/2, 3/4, etc. produce exact rational numbers (not Rust integer division).

Multi-argument functions

• log(x, base) → logarithm of x with given base
• diff(f, x) → formal derivative of f with respect to x (unevaluated)
• factorial(n) → n!
• binomial(n, k) or C(n, k) → binomial coefficient C(n,k)

Examples

use symplex::prelude::*;
use symplex::expr;

let ctx = Context::new();
syms!(ctx; x, y);
let e = expr!(x^2 + 2*x + 1);
let f = expr!(sin(x)^2 + cos(x)^2);

Limitations

• Implicit multiplication (2x) is not supported. Write 2*x.
• Only the listed built-in functions are recognised.