/**
* Set a named constant (constants names are not case-sensitive). Constants are like variables but
* are not cleared by clear(). Variables of the same name have precedence over constants.
*/
public MathEval setConstant(String nam, Double val) {
if (constants.get(nam) != null) {
throw new IllegalArgumentException("Constants may not be redefined");
}
validateName(nam);
constants.put(nam, val);
return this;
}
/**
* Set a named variable (variables names are not case-sensitive). If the value is null, the
* variable is removed.
*/
public MathEval setVariable(String nam, Double val) {
validateName(nam);
if (val == null) {
variables.remove(nam);
} else {
variables.put(nam, val);
}
return this;
}
/**
* Set a function handler for the specific named function optionally tagging the function as
* impure, replacing any existing handler for the given name; if the handler is null the function
* handler is removed.
*
* <p>Pure functions have results which depend purely on their arguments; given constant arguments
* they will have a constant result. Impure functions are rare.
*/
public MathEval setFunctionHandler(String nam, FunctionHandler hdl, boolean impure) {
validateName(nam);
if (hdl == null) {
pureFunctions.remove(nam);
impureFunctions.remove(nam);
} else if (impure) {
pureFunctions.remove(nam);
impureFunctions.put(nam, hdl);
} else {
pureFunctions.put(nam, hdl);
impureFunctions.remove(nam);
}
return this;
}