129 lines
3.4 KiB
Dart
129 lines
3.4 KiB
Dart
import 'dart:math' as Math;
|
|
|
|
import 'package:d4rt/d4rt.dart';
|
|
import 'formula_models.dart';
|
|
|
|
|
|
|
|
|
|
|
|
|
|
/// Exception thrown when formula evaluation fails
|
|
class FormulaEvaluationException implements Exception {
|
|
final String message;
|
|
final Object? cause;
|
|
|
|
const FormulaEvaluationException(this.message, [this.cause]);
|
|
|
|
@override
|
|
String toString() => 'FormulaEvaluationException: $message'
|
|
'${cause != null ? ' (caused by: $cause)' : ''}';
|
|
}
|
|
|
|
class MyMath{
|
|
static Number log(Number x) => Math.log(x);
|
|
static Number pow(Number b, Number e) => Math.pow(b,e) as Number;
|
|
}
|
|
|
|
class FormulaEvaluator {
|
|
final D4rt _interpreter;
|
|
|
|
FormulaEvaluator([D4rt? interpreter]) : _interpreter = interpreter ?? D4rt(){
|
|
prepareInterpreter(_interpreter);
|
|
}
|
|
|
|
Number getNumberValueOf(String s){
|
|
return double.parse(s);
|
|
}
|
|
|
|
void prepareInterpreter(D4rt interpreter){
|
|
final myMathDefinition = BridgedClass(
|
|
nativeType: MyMath,
|
|
name: 'Math',
|
|
staticMethods: {
|
|
'pow': (visitor, positionalArgs, namedArgs) {
|
|
final Number base = getNumberValueOf( positionalArgs[0].toString() );
|
|
final Number exp = getNumberValueOf( positionalArgs[1].toString() );
|
|
return MyMath.pow(base,exp);
|
|
},
|
|
}
|
|
);
|
|
|
|
interpreter.registerBridgedClass(myMathDefinition, 'package:myapp/my_math.dart');
|
|
}
|
|
|
|
|
|
dynamic evaluate(Formula formula, Map<String, dynamic> inputValues) {
|
|
_validateInputValues(formula, inputValues);
|
|
|
|
try {
|
|
// Build the complete d4rt source code with variable declarations
|
|
final completeSource = _buildCompleteSource(formula, inputValues);
|
|
|
|
// Execute the code using d4rt (no args needed since variables are in source)
|
|
final result = _interpreter.execute(source: completeSource);
|
|
|
|
return result;
|
|
} catch (e) {
|
|
throw FormulaEvaluationException(
|
|
'Failed to execute formula "${formula.name}"',
|
|
e,
|
|
);
|
|
}
|
|
}
|
|
|
|
void _validateInputValues(Formula formula, Map<String, dynamic> inputValues) {
|
|
final missingVars = <String>[];
|
|
|
|
for (final inputVar in formula.inputVarNames()) {
|
|
if (!inputValues.containsKey(inputVar)) {
|
|
missingVars.add(inputVar);
|
|
}
|
|
}
|
|
|
|
if (missingVars.isNotEmpty) {
|
|
throw FormulaEvaluationException(
|
|
'Missing required input variables for formula "${formula.name}": '
|
|
'${missingVars.join(', ')}',
|
|
);
|
|
}
|
|
}
|
|
|
|
String getOutputVariableName(Formula formula) {
|
|
return formula.output.name;
|
|
}
|
|
|
|
String getOutputVariableMagnitude(Formula formula) {
|
|
return formula.output.unit;
|
|
}
|
|
|
|
List<String> getInputVariableOrder(Formula formula) {
|
|
return formula.inputVarNames()..sort();
|
|
}
|
|
|
|
String _buildCompleteSource(Formula formula, Map<String, dynamic> inputValues) {
|
|
final buffer = StringBuffer();
|
|
|
|
buffer.writeln("import 'package:myapp/my_math.dart';");
|
|
buffer.writeln("main(){");
|
|
|
|
for (final entry in inputValues.entries) {
|
|
final varName = entry.key;
|
|
final value = entry.value;
|
|
|
|
if (value is String) {
|
|
final escapedValue = value.replaceAll('"', '\\"');
|
|
buffer.writeln('var $varName = "$escapedValue";');
|
|
} else {
|
|
buffer.writeln('var $varName = $value;');
|
|
}
|
|
}
|
|
buffer.writeln("late var ${getOutputVariableName(formula)};");
|
|
|
|
buffer.writeln(formula.d4rtCode);
|
|
buffer.writeln("return ${getOutputVariableName(formula)};");
|
|
buffer.writeln("}");
|
|
|
|
return buffer.toString();
|
|
}
|
|
}
|