private Function evaluateFunction(SEXP functionExp, Environment rho) {
if (functionExp instanceof Symbol) {
Symbol symbol = (Symbol) functionExp;
Function fn = rho.findFunction(this, symbol);
if (fn == null) {
throw new EvalException("could not find function '%s'", symbol.getPrintName());
}
return fn;
} else {
SEXP evaluated = evaluate(functionExp, rho).force(this);
if (!(evaluated instanceof Function)) {
throw new EvalException(
"'function' of lang expression is of unsupported type '%s'", evaluated.getTypeName());
}
return (Function) evaluated;
}
}
private static SubstituteContext buildContext(Context context, SEXP evaluatedEnv) {
if (evaluatedEnv instanceof Environment) {
if (context.getGlobalEnvironment() == evaluatedEnv) {
return new GlobalEnvironmentContext();
} else {
return new EnvironmentContext((Environment) evaluatedEnv);
}
} else if (evaluatedEnv instanceof ListVector) {
return new ListContext((ListVector) evaluatedEnv);
} else if (evaluatedEnv instanceof PairList) {
return new PairListContext((PairList) evaluatedEnv);
} else {
throw new EvalException(
"Cannot substitute using environment of type %s: expected list, pairlist, or environment",
evaluatedEnv.getTypeName());
}
}
