dart Set literals instead of json

lib/formula_models.dart

@@ -65,5 +65,24 @@ class Formula {
       Object.hash(name, ListEquality().hash(input), output, d4rtCode);
 
   List<String> inputVarNames() => input.map( (v) => v.name ).toList(growable: false);
+
+  factory Formula.fromSetLiteral(Map<String, Object> set ) {
+
+      VariableSpec parseVar(Map<String, String> varSpec ){
+        String name = varSpec.get("name");
+        String magnitude = varSpec.get("magnitude");
+        return VariableSpec(name: name, magnitude: magnitude);
+      }
+
+      String name = set.get("name");
+      List<Map<String,String>> inputSet = set.get("input");
+      List<VariableSpec> input = inputSet.map(parseVar).toList(growable:false);
+      Map<String,String> outputSet = set.get("output");
+      VariableSpec output = parseVar(outputSet);
+      String d4rtCode = set.get("d4rtCode");
+
+      return new Formula(name:name, input:input, output:output, d4rtCode:d4rtCode );
+
+  }
 }
 

test/formula_models_test.dart

@@ -1,7 +1,33 @@
 import 'dart:convert';
 
+import 'package:d4rt_formulas/formula_evaluator.dart';
 import 'package:test/test.dart';
 import 'package:d4rt_formulas/formula_models.dart';
 
 void main() {
+
+  test('Parses Newton\'s second law formula from set literal', () {
+    final setLiteral = {
+      "name": "Newton's second law",
+      "input": [
+        { "name": 'm', "magnitude": 'mass'},
+        { "name": 'a', "magnitude": 'acceleration'}
+      ],
+      "output": { "name": 'F', "magnitude": 'force'},
+      "d4rtCode": '''
+              return a * m;
+          '''
+    };
+
+    final formula = Formula.fromSetLiteral(setLiteral);
+    final evaluator = new FormulaEvaluator();
+
+    final result = evaluator.evaluate(formula, {
+      'm': 10.0, // 10 kg
+      'a': 9.8, // 9.8 m/s²
+    });
+
+    expect(result, 98.0); // F = m * a = 10 * 9.8 = 98 N
+  });
+
 }