TemplateDesigner: SystemVars

2026-08-31 23:47:48 +02:00
parent 11ef73ab1f
commit c6efdab9ef
7 changed files with 139 additions and 5 deletions
@@ -0,0 +1,48 @@
+namespace LehrerApp.Templating;
+
+internal static class SystemVariables
+{
+    internal const string CurrentPage = "curPage";
+    internal const string MaximumPageNumber = "maxPageNum";
+    internal const string Today = "today";
+
+    private static readonly string[] Names = [CurrentPage, MaximumPageNumber, Today];
+
+    internal static bool IsStandalone(string value) =>
+        TryRead(value, 0, out var length) && length == value.Length;
+
+    internal static bool Contains(string value) => Names.Any(name =>
+        value.Contains("$$" + name, StringComparison.Ordinal));
+
+    internal static bool TryRead(string source, int index, out int length)
+    {
+        length = 0;
+        if (index < 0 || index + 2 > source.Length || source[index] != '$' || source[index + 1] != '$')
+            return false;
+        foreach (var name in Names)
+        {
+            var token = "$$" + name;
+            if (!source.AsSpan(index).StartsWith(token, StringComparison.Ordinal)) continue;
+            var end = index + token.Length;
+            if (end < source.Length && (char.IsLetterOrDigit(source[end]) || source[end] is '_' or '-' or '.'))
+                continue;
+            length = token.Length;
+            return true;
+        }
+        return false;
+    }
+
+    internal static IEnumerable<(string Text, string? Name)> Split(string source)
+    {
+        var literalStart = 0;
+        for (var index = 0; index < source.Length;)
+        {
+            if (!TryRead(source, index, out var length)) { index++; continue; }
+            if (index > literalStart) yield return (source[literalStart..index], null);
+            yield return (source.Substring(index, length), source.Substring(index + 2, length - 2));
+            index += length;
+            literalStart = index;
+        }
+        if (literalStart < source.Length) yield return (source[literalStart..], null);
+    }
+}