feat: implement non-boolean format specifiers (#22)

CHANGELOG.md

@@ -12,6 +12,19 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   - All header/footer types supported: Default, First Page, Even Page
   - Same syntax and features as document body - no additional API calls needed
   - Formatting is preserved in headers and footers
+- **Number and Currency Format Specifiers** - Format numeric values directly in placeholders (#22)
+  - `:currency` — locale-aware currency formatting (e.g., `$1,234.56` or `1.234,56 €`)
+  - `:number:FORMAT` — any .NET numeric format string (e.g., `:number:N2`, `:number:F3`, `:number:P`)
+  - Works with int, long, decimal, double, and float values
+  - Supports compound format specifiers in placeholder regex
+- **String Format Specifiers** - Transform string casing in placeholders (#22)
+  - `:uppercase` — convert to UPPERCASE
+  - `:lowercase` — convert to lowercase
+- **Date Format Specifiers** - Format dates directly in placeholders (#22)
+  - `:date:FORMAT` — any .NET date format string (e.g., `:date:yyyy-MM-dd`, `:date:MMMM d, yyyy`)
+  - Supports DateTime, DateTimeOffset, and ISO date string values
+  - Culture-aware month/day names
+- **GUI Culture Selector** - Dropdown to choose formatting culture (Invariant, en-US, de-DE, fr-FR, es-ES)
 
 ## [1.5.0] - 2026-02-13
 

CLAUDE.md

@@ -294,6 +294,10 @@ The library uses a **visitor pattern** for processing Word documents, enabling:
 - Nested: `{{Customer.Address.City}}`
 - Array indexing: `{{Items[0].Name}}`
 - Dictionary: `{{Settings[Theme]}}` or `{{Settings.Theme}}`
+- Currency format: `{{Amount:currency}}`
+- Number format: `{{Value:number:N2}}`, `{{Rate:number:F3}}`, `{{Pct:number:P}}`
+- String format: `{{Name:uppercase}}`, `{{Code:lowercase}}`
+- Date format: `{{OrderDate:date:yyyy-MM-dd}}`, `{{Date:date:MMMM d, yyyy}}`
 
 ### Conditional Syntax
 ```

README.md

@@ -189,6 +189,32 @@ To disable (for backward compatibility):
 var options = new PlaceholderReplacementOptions { EnableNewlineSupport = false };
 ```
 
+### Format Specifiers
+
+Control how values are displayed using format specifiers:
+
+```
+{{Name:uppercase}}            → ALICE JOHNSON
+{{Code:lowercase}}            → abc-123
+{{Amount:currency}}           → $1,234.57 (en-US) or 1.234,57 € (de-DE)
+{{Value:number:N2}}           → 1,234.57
+{{Percentage:number:P}}       → 12.34 %
+{{OrderDate:date:yyyy-MM-dd}} → 2024-01-15
+{{OrderDate:date:MMMM d, yyyy}} → January 15, 2024
+{{IsActive:checkbox}}         → ☑ or ☐
+{{IsActive:yesno}}            → Yes or No
+```
+
+All format specifiers are culture-aware:
+
+```csharp
+var options = new PlaceholderReplacementOptions
+{
+    Culture = new CultureInfo("de-DE")  // Affects currency, numbers, dates, and localized text
+};
+var processor = new DocumentTemplateProcessor(options);
+```
+
 ### Standalone Condition Evaluation
 
 Use Templify's condition engine without processing Word documents:

TriasDev.Templify.Gui/Models/CultureOption.cs

@@ -0,0 +1,14 @@
+// Copyright (c) 2025 TriasDev GmbH & Co. KG
+// Licensed under the MIT License. See LICENSE file in the project root for full license information.
+
+using System.Globalization;
+
+namespace TriasDev.Templify.Gui.Models;
+
+/// <summary>
+/// Represents a culture option for the UI dropdown.
+/// </summary>
+public record CultureOption(string DisplayName, CultureInfo Culture)
+{
+    public override string ToString() => DisplayName;
+}

TriasDev.Templify.Gui/Services/ITemplifyService.cs

@@ -2,6 +2,7 @@
 // Licensed under the MIT License. See LICENSE file in the project root for full license information.
 
 using System;
+using System.Globalization;
 using System.Threading.Tasks;
 using TriasDev.Templify.Core;
 using TriasDev.Templify.Gui.Models;
@@ -19,11 +20,13 @@ public interface ITemplifyService
     /// <param name="templatePath">Path to the template file (.docx).</param>
     /// <param name="jsonPath">Optional path to JSON data file for validation.</param>
     /// <param name="enableHtmlEntityReplacement">Enable HTML entity replacement (e.g., &lt;br&gt; to line break).</param>
+    /// <param name="culture">Culture for formatting. Defaults to InvariantCulture.</param>
     /// <returns>Validation result with errors and warnings.</returns>
     Task<ValidationResult> ValidateTemplateAsync(
         string templatePath,
         string? jsonPath = null,
-        bool enableHtmlEntityReplacement = false);
+        bool enableHtmlEntityReplacement = false,
+        CultureInfo? culture = null);
 
     /// <summary>
     /// Processes a template with JSON data and generates output.
@@ -32,12 +35,14 @@ Task<ValidationResult> ValidateTemplateAsync(
     /// <param name="jsonPath">Path to JSON data file.</param>
     /// <param name="outputPath">Path for the output file.</param>
     /// <param name="enableHtmlEntityReplacement">Enable HTML entity replacement (e.g., &lt;br&gt; to line break).</param>
+    /// <param name="culture">Culture for formatting. Defaults to InvariantCulture.</param>
     /// <param name="progress">Optional progress reporter.</param>
     /// <returns>Processing result with statistics and any errors.</returns>
     Task<UiProcessingResult> ProcessTemplateAsync(
         string templatePath,
         string jsonPath,
         string outputPath,
         bool enableHtmlEntityReplacement = false,
+        CultureInfo? culture = null,
         IProgress<double>? progress = null);
 }

TriasDev.Templify.Gui/Services/TemplifyService.cs

@@ -24,14 +24,16 @@ public class TemplifyService : ITemplifyService
     public async Task<ValidationResult> ValidateTemplateAsync(
         string templatePath,
         string? jsonPath = null,
-        bool enableHtmlEntityReplacement = false)
+        bool enableHtmlEntityReplacement = false,
+        CultureInfo? culture = null)
     {
         return await Task.Run(() =>
         {
+            CultureInfo effectiveCulture = culture ?? CultureInfo.InvariantCulture;
             PlaceholderReplacementOptions options = new PlaceholderReplacementOptions
             {
                 MissingVariableBehavior = MissingVariableBehavior.LeaveUnchanged,
-                Culture = CultureInfo.InvariantCulture,
+                Culture = effectiveCulture,
                 TextReplacements = enableHtmlEntityReplacement ? TextReplacements.HtmlEntities : null
             };
 
@@ -63,6 +65,7 @@ public async Task<UiProcessingResult> ProcessTemplateAsync(
         string jsonPath,
         string outputPath,
         bool enableHtmlEntityReplacement = false,
+        CultureInfo? culture = null,
         IProgress<double>? progress = null)
     {
         return await Task.Run(() =>
@@ -83,10 +86,11 @@ public async Task<UiProcessingResult> ProcessTemplateAsync(
                 progress?.Report(0.3);
 
                 // Configure options with optional HTML entity replacement
+                CultureInfo effectiveCulture = culture ?? CultureInfo.InvariantCulture;
                 PlaceholderReplacementOptions options = new PlaceholderReplacementOptions
                 {
                     MissingVariableBehavior = MissingVariableBehavior.LeaveUnchanged,
-                    Culture = CultureInfo.InvariantCulture,
+                    Culture = effectiveCulture,
                     TextReplacements = enableHtmlEntityReplacement ? TextReplacements.HtmlEntities : null
                 };
 

TriasDev.Templify.Gui/ViewModels/MainWindowViewModel.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Collections.ObjectModel;
 using System.Diagnostics;
+using System.Globalization;
 using System.IO;
 using System.Linq;
 using System.Threading.Tasks;
@@ -56,6 +57,24 @@ public partial class MainWindowViewModel : ViewModelBase
     [ObservableProperty]
     private bool _enableHtmlEntityReplacement;
 
+    /// <summary>
+    /// Available cultures for formatting.
+    /// </summary>
+    public ObservableCollection<CultureOption> AvailableCultures { get; } = new(
+    [
+        new CultureOption("Invariant", CultureInfo.InvariantCulture),
+        new CultureOption("English (US)", new CultureInfo("en-US")),
+        new CultureOption("German (DE)", new CultureInfo("de-DE")),
+        new CultureOption("French (FR)", new CultureInfo("fr-FR")),
+        new CultureOption("Spanish (ES)", new CultureInfo("es-ES")),
+    ]);
+
+    /// <summary>
+    /// Gets or sets the selected culture for formatting.
+    /// </summary>
+    [ObservableProperty]
+    private CultureOption _selectedCulture = null!;
+
     /// <summary>
     /// Stores the last processing result to enable warning report generation.
     /// </summary>
@@ -69,6 +88,7 @@ public MainWindowViewModel(
     {
         _templifyService = templifyService;
         _fileDialogService = fileDialogService;
+        _selectedCulture = AvailableCultures[0];
     }
 
     [RelayCommand]
@@ -121,7 +141,8 @@ private async Task ValidateTemplateAsync()
             ValidationResult validation = await _templifyService.ValidateTemplateAsync(
                 TemplatePath,
                 JsonPath,
-                EnableHtmlEntityReplacement);
+                EnableHtmlEntityReplacement,
+                SelectedCulture.Culture);
 
             if (validation.IsValid)
             {
@@ -196,6 +217,7 @@ private async Task ProcessTemplateAsync()
                 JsonPath,
                 OutputPath,
                 EnableHtmlEntityReplacement,
+                SelectedCulture.Culture,
                 progressReporter);
 
             // Store for warning report generation
@@ -282,6 +304,7 @@ private void Clear()
         StatusMessage = "Ready";
         Progress = 0;
         LastProcessingResult = null;
+        SelectedCulture = AvailableCultures[0];
     }
 
     [RelayCommand(CanExecute = nameof(CanGenerateWarningReport))]

TriasDev.Templify.Gui/Views/MainWindow.axaml

@@ -64,10 +64,17 @@
         </Grid>
 
         <!-- Options Section -->
-        <StackPanel Grid.Row="4" Orientation="Horizontal" Margin="0,0,0,20">
+        <StackPanel Grid.Row="4" Orientation="Horizontal" Spacing="20" Margin="0,0,0,20">
             <CheckBox Content="Enable HTML Entity Replacement"
                       IsChecked="{Binding EnableHtmlEntityReplacement}"
                       ToolTip.Tip="Convert HTML entities like &lt;br&gt;, &amp;nbsp;, &amp;lt;, etc. to Word equivalents"/>
+            <StackPanel Orientation="Horizontal" Spacing="5">
+                <TextBlock Text="Culture:" VerticalAlignment="Center"/>
+                <ComboBox ItemsSource="{Binding AvailableCultures}"
+                          SelectedItem="{Binding SelectedCulture}"
+                          Width="160"
+                          ToolTip.Tip="Culture used for number, currency, date formatting and string casing"/>
+            </StackPanel>
         </StackPanel>
 
         <!-- Action Buttons -->