Fix opposite_eq method.

Simplify method in Simplify trait.

Fix distributive law.

Response for the simplify endpoint.

HTTP client.

camelCase and SCREAMING_SNAKE_CASE for struct and enum

http/common.js

@@ -0,0 +1,8 @@
+/**
+ * Encode the given string as a URI component, and set the request variable "expression" to the result.
+ * @param {string} expression
+ * @returns {void}
+ */
+export function expression(expression) {
+    request.variables.set("expression", encodeURIComponent(expression))
+}