Silently fail is user enters a NAN expression in parameter field.

src/Quantity.cpp

@@ -33,7 +33,7 @@ std::string Quantity::getDisplayValueString() {
 void Quantity::setDisplayValueString(std::string s) {
 	static const double inf = INFINITY;
 	static te_variable vars[] = {
-		{"inf", &inf},
+		{"inf", &inf, TE_VARIABLE, NULL},
 	};
 	te_expr* expr = te_compile(s.c_str(), vars, LENGTHOF(vars), NULL);
 	if (!expr)
@@ -41,6 +41,9 @@ void Quantity::setDisplayValueString(std::string s) {
 
 	double result = te_eval(expr);
 	te_free(expr);
+	if (std::isnan(result))
+		return;
+
 	setDisplayValue(result);
 }
 

src/engine/ParamQuantity.cpp

@@ -80,11 +80,17 @@ float ParamQuantity::getDisplayValue() {
 void ParamQuantity::setDisplayValue(float displayValue) {
 	if (!module)
 		return;
+
+	// Handle displayOffset
 	float v = displayValue - displayOffset;
+
+	// Handle displayMultiplier
 	if (displayMultiplier == 0.f)
 		v = 0.f;
 	else
 		v /= displayMultiplier;
+
+	// Handle displayBase
 	if (displayBase == 0.f) {
 		// Linear
 		// v is unchanged
@@ -97,6 +103,10 @@ void ParamQuantity::setDisplayValue(float displayValue) {
 		// Exponential
 		v = std::log(v) / std::log(displayBase);
 	}
+
+	if (std::isnan(v))
+		return;
+
 	setValue(v);
 }