Function build_function 

pub fn build_function(expr: Expr) -> Result<JITFunction, EquationError>

Builds a JIT-compiled function from a mathematical expression.

This function compiles an expression AST into optimized machine code using Cranelift. The compilation process includes:

• Expression simplification through multiple passes
• Constant folding and dead code elimination
• Optimal instruction selection
• Memory access optimization

Arguments

• expr - The expression AST to compile

Returns

A thread-safe function that evaluates the expression given input values

Errors

Returns an EquationError if compilation fails for any reason.