Added share menu to FormulaScreen

lib/ai/formula_list.dart

@@ -1,6 +1,8 @@
+import 'package:d4rt_formulas/error_handler.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart'; // For Clipboard
 import 'package:d4rt_formulas/formula_models.dart';
+import 'package:get_it/get_it.dart';
 import '../corpus.dart';
 import '../set_utils.dart';
 import 'formula_screen.dart';
@@ -22,6 +24,53 @@ class FormulaList extends StatefulWidget {
 
   @override
   State<FormulaList> createState() => _FormulaListState();
+
+  static String _formulaAndDependenciesToExportStringLiteral(Formula formula) {
+    final corpus = GetIt.instance.get<Corpus>();
+    final dependencies = corpus.withDependencies(formula);
+    final dependenciesAsMap = dependencies.map((f) => f.toMap()).toList();
+    for( final f in dependenciesAsMap ){
+      f.remove("uuid");
+    }
+    return SetUtils.prettyPrint(dependenciesAsMap);
+  }
+
+
+  static void shareFormula(Formula formula) async {
+    try {
+      final exportString = _formulaAndDependenciesToExportStringLiteral(formula);
+
+      // Share the string
+      await share_plus.SharePlus.instance.share(
+        share_plus.ShareParams(
+          text: exportString,
+          subject: 'Sharing formula: ${formula.name}',
+        ),
+      );
+    } catch (e, st) {
+      errorHandler.notify(e, st);
+    }
+  }
+
+  static void copyFormula(BuildContext context, Formula formula) async {
+    try {
+      final exportString = _formulaAndDependenciesToExportStringLiteral(formula);
+
+      // Copy to clipboard
+      await Clipboard.setData(ClipboardData(text: exportString));
+
+      // Show a snackbar to confirm
+      ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(
+          content: Text('Formula and dependencies copied to clipboard!'),
+          duration: Duration(seconds: 2),
+        ),
+      );
+    } catch (e, st) {
+      errorHandler.notify(e, st);
+    }
+  }
+
 }
 
 class _FormulaListState extends State<FormulaList> {
@@ -56,49 +105,6 @@ class _FormulaListState extends State<FormulaList> {
     }).toList();
   }
 
-  String _formulaAndDependenciesToExportStringLiteral(Formula formula) {
-    final dependencies = widget.corpus.withDependencies(formula);
-    final dependenciesAsMap = dependencies.map((f) => f.toMap()).toList();
-    for( final f in dependenciesAsMap ){
-      f.remove("uuid");
-    }
-    return SetUtils.prettyPrint(dependenciesAsMap);
-  }
-
-  void _shareFormula(Formula formula) async {
-    try {
-      final exportString = _formulaAndDependenciesToExportStringLiteral(formula);
-
-      // Share the string
-      await share_plus.SharePlus.instance.share(
-        share_plus.ShareParams(
-          text: exportString,
-          subject: 'Sharing formula: ${formula.name}',
-        ),
-      );
-    } catch (e) {
-      _showErrorDialog('Error sharing formula: $e');
-    }
-  }
-
-  void _copyFormula(Formula formula) async {
-    try {
-      final exportString = _formulaAndDependenciesToExportStringLiteral(formula);
-      
-      // Copy to clipboard
-      await Clipboard.setData(ClipboardData(text: exportString));
-      
-      // Show a snackbar to confirm
-      ScaffoldMessenger.of(context).showSnackBar(
-        SnackBar(
-          content: Text('Formula and dependencies copied to clipboard!'),
-          duration: Duration(seconds: 2),
-        ),
-      );
-    } catch (e) {
-      _showErrorDialog('Error copying formula: $e');
-    }
-  }
 
   void _showErrorDialog(String message) {
     showDialog(
@@ -155,9 +161,9 @@ class _FormulaListState extends State<FormulaList> {
                       tooltip: 'Share or copy to clipboard',
                       onSelected: (value) {
                         if (value == 'share') {
-                          _shareFormula(formula);
+                          FormulaList.shareFormula(formula);
                         } else if (value == 'copy') {
-                          _copyFormula(formula);
+                          FormulaList.copyFormula(context, formula);
                         }
                       },
                       itemBuilder: (context) => [

lib/ai/formula_screen.dart

@@ -9,6 +9,7 @@ import '../corpus.dart';
 import '../error_handler.dart';
 import '../value_formatter.dart';
 import 'd4rt_editing_controller.dart';
+import 'formula_list.dart';
 import 'unit_dropdown.dart';
 import 'formula_editor.dart';
 
@@ -157,6 +158,42 @@ class _FormulaScreenState extends State<FormulaScreen> {
       appBar: AppBar(
         title: Text(formula.name),
         actions: [
+          PopupMenuButton(
+            icon: const Icon(Icons.share),
+            tooltip: 'Share or copy to clipboard',
+            onSelected: (value) {
+              if (value == 'share') {
+                FormulaList.shareFormula(formula.originalFormula);
+              } else if (value == 'copy') {
+                FormulaList.copyFormula(context, formula.originalFormula);
+              }
+            },
+            itemBuilder: (context) => [
+              PopupMenuItem(
+                value: 'share',
+                child: Row(
+                  mainAxisSize: MainAxisSize.min,
+                  children: [
+                    const Icon(Icons.share, size: 20),
+                    const SizedBox(width: 8),
+                    Flexible(child: Text('Share', softWrap: false)),
+                  ],
+                ),
+              ),
+              PopupMenuItem(
+                value: 'copy',
+                child: Row(
+                  mainAxisSize: MainAxisSize.min,
+                  children: [
+                    const Icon(Icons.copy, size: 20),
+                    const SizedBox(width: 8),
+                    Flexible(child: Text('Copy to clipboard', softWrap: false)),
+                  ],
+                ),
+              ),
+            ],
+          ),
+
           IconButton(
             icon: const Icon(Icons.edit),
             onPressed: formula is DerivedFormula

lib/formula_evaluator.dart

@@ -423,7 +423,7 @@ Number functionSolver(
       final Number dy = numericalDerivative(x);
 
       if (dy == 0 || dy.abs() < 1e-12) {
-        throw NoSolutionException("Derivative is zero or too small, cannot continue Newton-Raphson.");
+        throw NoSolutionException("Derivative is zero or too small, cannot continue Newton-Raphson: $dy");
       }
 
       final Number delta = y / dy;
@@ -436,7 +436,7 @@ Number functionSolver(
       // If step exploded, cap the step to a reasonable multiple of `step`
       final Number maxStepAllowed = step * 1e6;
       if ((xNew - x).abs() > maxStepAllowed) {
-        xNew = x + (delta.isNegative ? -maxStepAllowed : maxStepAllowed);
+        xNew = x - (delta.isNegative ? -maxStepAllowed : maxStepAllowed);
       }
 
       x = xNew;