getExpression method
Returns the bound expression for the given variable.
Performs recursive lookup through parentScope
.
Throws a StateError, if variable is still unbound at the root scope.
Implementation
Expression getExpression(String varName) {
if (variables.containsKey(varName)) {
return variables[varName]!;
}
if (parentScope != null) {
return parentScope!.getExpression(varName);
} else {
throw StateError('Variable not bound: $varName');
}
}