ExpressionTest

import church.util.Entry;
import church.util.HashMap;

import Expression;

import church.math.operators.Transcendental;

log(Expression: a) = app("log", a);
exp(Expression: a) = app("exp", a);
sqrt(Expression: a) = app("sqrt", a);

sin(Expression: a) = app("sin", a);
cos(Expression: a) = app("cos", a);
tan(Expression: a) = app("tan", a);

asin(Expression: a) = app("asin", a);
acos(Expression: a) = app("acos", a);
atan(Expression: a) = app("atan", a);

funNameToFunction(name) = {
    "log"  −> log,
    "exp"  −> exp,
    "sqrt" −> sqrt,
    "sin"  −> sin,
    "cos"  −> cos,
    "tan"  −> tan,
    "asin" −> asin,
    "acos" −> acos,
    "atan" −> atan
}.get(name);

//foo(x) = x * x + (x * x + const(1.0)) / x + const(2.0) * x + const(3.0);
//foo(x) = acos(x * sin(x) + multiplicative_identity);
//foo(x) = tan(x) + const(1.0);
//foo(x) = x * x + const(1.0);
foo(x) = cos(x ^ 2.0 + const(1.0));
//foo(x) = x * x + multiplicative_identity;
//foo(x) = x^3.0 + const(2.0) * x^2.0 + const(3.0) * x + const(4.0);

test(funNameToFunction, fn, x0, expectedFp0) = {
    varName = "x";
    varNameToValue = name −> if name == varName then x0 else error("Undefined variable");
    x = var(varName);
    // evaluate the function
    f = fn(x);
    output << "f(x)  = " << f << "\n";
    f0 = evaluate(funNameToFunction, f, varNameToValue);
    output << "f(1)  = " << f0 << "\n";
    output << "\n";
}

void: main(String[]: args) = {
    test(funNameToFunction, foo, 1.0, -1.8185948536513634)
}