Adds calendar functions

src/libraries/Microsoft.PowerFx.Interpreter/Functions/Library.cs

@@ -1231,6 +1231,14 @@ static Library()
                     returnBehavior: ReturnBehavior.AlwaysEvaluateAndReturnResult,
                     targetFunction: Month)
             },
+            {
+                BuiltinFunctionsCore.MonthsLong,
+                NoErrorHandling(CalendarMonthsLong)
+            },
+            {
+                BuiltinFunctionsCore.MonthsShort,
+                NoErrorHandling(CalendarMonthsShort)
+            },
             {
                 BuiltinFunctionsCore.Not,
                 StandardErrorHandling<BooleanValue>(
@@ -1863,6 +1871,14 @@ static Library()
                     returnBehavior: ReturnBehavior.AlwaysEvaluateAndReturnResult,
                     targetFunction: Weekday)
             },
+            {
+                BuiltinFunctionsCore.WeekdaysLong,
+                NoErrorHandling(CalendarWeekdaysLong)
+            },
+            {
+                BuiltinFunctionsCore.WeekdaysShort,
+                NoErrorHandling(CalendarWeekdaysShort)
+            },
             {
                 BuiltinFunctionsCore.WeekNum,
                 StandardErrorHandling<FormulaValue>(

src/libraries/Microsoft.PowerFx.Interpreter/Functions/LibraryDate.cs

@@ -924,6 +924,48 @@ private static double WeekStartDay(double startOfWeek)
             return 0;
         }
 
+        private static FormulaValue CalendarMonthsLong(EvalVisitor runner, EvalVisitorContext context, IRContext irContext, FormulaValue[] args)
+        {
+            var rows = Enumerable
+                .Range(1, 12)
+                .Select(month => new DateTime(2024, month, 2).ToString("MMMM", runner.CultureInfo))
+                .Select(monthName => new StringValue(IRContext.NotInSource(FormulaType.String), monthName));
+
+            return new InMemoryTableValue(irContext, StandardTableNodeRecords(irContext, rows.ToArray(), forceSingleColumn: true));
+        }
+
+        private static FormulaValue CalendarMonthsShort(EvalVisitor runner, EvalVisitorContext context, IRContext irContext, FormulaValue[] args)
+        {
+            var rows = Enumerable
+                .Range(1, 12)
+                .Select(month => new DateTime(2024, month, 2).ToString("MMM", runner.CultureInfo).TrimEnd('.'))
+                .Select(monthName => new StringValue(IRContext.NotInSource(FormulaType.String), monthName));
+
+            return new InMemoryTableValue(irContext, StandardTableNodeRecords(irContext, rows.ToArray(), forceSingleColumn: true));
+        }
+
+        private static FormulaValue CalendarWeekdaysLong(EvalVisitor runner, EvalVisitorContext context, IRContext irContext, FormulaValue[] args)
+        {
+            var anySunday = new DateTime(2024, 6, 2);
+            var rows = Enumerable
+                .Range(0, 7)
+                .Select(weekday => anySunday.AddDays(weekday).ToString("dddd", runner.CultureInfo))
+                .Select(weekdayName => new StringValue(IRContext.NotInSource(FormulaType.String), weekdayName));
+
+            return new InMemoryTableValue(irContext, StandardTableNodeRecords(irContext, rows.ToArray(), forceSingleColumn: true));
+        }
+
+        private static FormulaValue CalendarWeekdaysShort(EvalVisitor runner, EvalVisitorContext context, IRContext irContext, FormulaValue[] args)
+        {
+            var anySunday = new DateTime(2024, 6, 2);
+            var rows = Enumerable
+                .Range(0, 7)
+                .Select(weekday => anySunday.AddDays(weekday).ToString("ddd", runner.CultureInfo).TrimEnd('.'))
+                .Select(weekdayName => new StringValue(IRContext.NotInSource(FormulaType.String), weekdayName));
+
+            return new InMemoryTableValue(irContext, StandardTableNodeRecords(irContext, rows.ToArray(), forceSingleColumn: true));
+        }
+
         private static double GetDoubleFromFormulaValue(FormulaValue fv, double defaultDouble = 0)
         {
             switch (fv)

src/libraries/Microsoft.PowerFx.Interpreter/Functions/StandardErrorHandling.cs

@@ -198,6 +198,17 @@ private static AsyncFunctionPtr NoErrorHandling(
             };
         }
 
+        // A wrapper for a function with no error handling behavior whatsoever.
+        private static AsyncFunctionPtr NoErrorHandling(
+            Func<EvalVisitor, EvalVisitorContext, IRContext, FormulaValue[], FormulaValue> targetFunction)
+        {
+            return (visitor, context, irContext, args) =>
+            {
+                var result = targetFunction(visitor, context, irContext, args);
+                return new ValueTask<FormulaValue>(result);
+            };
+        }
+
         // A wrapper for a function with no error handling behavior whatsoever.
         private static AsyncFunctionPtr NoErrorHandling(
             Func<EvalVisitor, EvalVisitorContext, IRContext, FormulaValue[], ValueTask<FormulaValue>> targetFunction)

src/tests/Microsoft.PowerFx.Core.Tests.Shared/ExpressionTestCases/Language.txt

@@ -1,2 +1,14 @@
 >> Language()
-"en-US"
+"en-US"
+
+>> Calendar.MonthsLong()
+Table({Value:"January"},{Value:"February"},{Value:"March"},{Value:"April"},{Value:"May"},{Value:"June"},{Value:"July"},{Value:"August"},{Value:"September"},{Value:"October"},{Value:"November"},{Value:"December"})
+
+>> Calendar.MonthsShort()
+Table({Value:"Jan"},{Value:"Feb"},{Value:"Mar"},{Value:"Apr"},{Value:"May"},{Value:"Jun"},{Value:"Jul"},{Value:"Aug"},{Value:"Sep"},{Value:"Oct"},{Value:"Nov"},{Value:"Dec"})
+
+>> Calendar.WeekdaysLong()
+Table({Value:"Sunday"},{Value:"Monday"},{Value:"Tuesday"},{Value:"Wednesday"},{Value:"Thursday"},{Value:"Friday"},{Value:"Saturday"})
+
+>> Calendar.WeekdaysShort()
+Table({Value:"Sun"},{Value:"Mon"},{Value:"Tue"},{Value:"Wed"},{Value:"Thu"},{Value:"Fri"},{Value:"Sat"})

src/tests/Microsoft.PowerFx.Interpreter.Tests.Shared/Docs/InterpreterBase.json

@@ -90,6 +90,8 @@
     "Minute",
     "Mod",
     "Month",
+    "MonthsLong",
+    "MonthsShort",
     "Not",
     "Now",
     "OptionSetInfo",
@@ -145,6 +147,8 @@
     "Value",
     "VarP",
     "Weekday",
+    "WeekdaysLong",
+    "WeekdaysShort",
     "WeekNum",
     "With",
     "Year"