dart Set literals instead of json

lib/formula_models.dart

@@ -1,8 +1,6 @@
-
 import 'package:d4rt/d4rt.dart';
 
 class VariableSpec {
-
   final String name;
   final String magnitude;
   static final MAGNITUDELESS = "magnitudeless";
@@ -35,7 +33,7 @@ class Formula {
     required this.input,
     required this.output,
     required this.d4rtCode,
-  }){
+  }) {
     validate();
   }
 
@@ -45,7 +43,6 @@ class Formula {
     }
   }
 
-
   @override
   String toString() =>
       'Formula(name: $name, input: $input, output: $output, d4rtCode: $d4rtCode)';
@@ -64,25 +61,48 @@ class Formula {
   int get hashCode =>
       Object.hash(name, ListEquality().hash(input), output, d4rtCode);
 
-  List<String> inputVarNames() => input.map( (v) => v.name ).toList(growable: false);
+  List<String> inputVarNames() =>
+      input.map((v) => v.name).toList(growable: false);
 
-  factory Formula.fromSetLiteral(Map<String, Object> set ) {
+  factory Formula.fromSet(Map<Object?, Object?> theSet) {
 
-      VariableSpec parseVar(Map<String, String> varSpec ){
+    Object safeGet(Map<Object?, Object?> map, String key){
-        String name = varSpec.get("name");
+      if( !map.containsKey(key) ){
-        String magnitude = varSpec.get("magnitude");
+        throw ArgumentError( "Key not found: $key -- $map" );
-        return VariableSpec(name: name, magnitude: magnitude);
       }
+      return map[key] ?? "Not possible!!!";
+    }
 
-      String name = set.get("name");
+    String stringValue(Map<Object?, Object?> map, String key){
-      List<Map<String,String>> inputSet = set.get("input");
+      return safeGet(map, key).toString();
-      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 );
+    List<Object?> listValue(Map<Object?, Object?> map, String key){
+      return safeGet(map,key) as List<Object?>;
+    }
 
+    Map<String, Object?> mapValue(Map<Object?, Object?> map, String key){
+      return safeGet(map,key) as Map<String, Object?>;
+    }
+
+    VariableSpec parseVar(Map<Object?, Object?> varSpec) {
+      String name = stringValue(varSpec, "name");
+      String magnitude = stringValue(varSpec, "magnitude");
+      return VariableSpec(name: name, magnitude: magnitude);
+    }
+
+    String name = stringValue( theSet, "name" );
+    final List<Object?> inputSet = listValue( theSet, "input");
+    List<VariableSpec> input = inputSet.map( (v) => parseVar(v as Map)).toList(growable: false);
+    Map<Object?, Object?> outputSet = theSet.get("output");
+    VariableSpec output = parseVar(outputSet);
+    String d4rtCode = theSet.get("d4rtCode");
+
+    return new Formula(
+      name: name,
+      input: input,
+      output: output,
+      d4rtCode: d4rtCode,
+    );
   }
 }
-

test/formula_models_test.dart

@@ -1,5 +1,6 @@
 import 'dart:convert';
 
+import 'package:d4rt/d4rt.dart';
 import 'package:d4rt_formulas/formula_evaluator.dart';
 import 'package:test/test.dart';
 import 'package:d4rt_formulas/formula_models.dart';
@@ -19,8 +20,8 @@ void main() {
           '''
     };
 
-    final formula = Formula.fromSetLiteral(setLiteral);
+    final formula = Formula.fromSet(setLiteral);
-    final evaluator = new FormulaEvaluator();
+    final evaluator = FormulaEvaluator();
 
     final result = evaluator.evaluate(formula, {
       'm': 10.0, // 10 kg
@@ -30,4 +31,39 @@ void main() {
     expect(result, 98.0); // F = m * a = 10 * 9.8 = 98 N
   });
 
+  test( 'd4rt parses formula from literal', (){
+    final literal = """
+    {
+      "name": "Newton's second law",
+      "input": [
+        { "name": 'm', "magnitude": 'mass'},
+        { "name": 'a', "magnitude": 'acceleration'}
+      ],
+      "output": { "name": 'F', "magnitude": 'force'},
+      "d4rtCode": '''
+              return a * m;
+          '''
+    }    
+    """;
+
+    var d4rt = D4rt();
+    final buffer = StringBuffer();
+    buffer.write( "main(){ return $literal; }");
+    final code = buffer.toString();
+
+    final Map<Object?, Object?> setLiteral = d4rt.execute(source: code);
+
+    final formula = Formula.fromSet(setLiteral);
+    final evaluator = 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
+
+  });
+
 }
+