ITemplatePrintable

ITemplatePrintable prints template texts without format provider.

/// <summary>Printable template text where format provider is internally assigned.</summary>
public interface ITemplatePrintable : ITemplatePrintableBase
{
    /// <summary>Print <paramref name="arguments"/> in placeholders.</summary>
    string Print(object?[]? arguments = null);
    /// <summary>Append to <paramref name="sb"/>.</summary>
    void AppendTo(StringBuilder sb, object?[]? arguments = null);
    /// <summary>Write to <paramref name="textWriter"/>.</summary>
    void WriteTo(TextWriter textWriter, object?[]? arguments = null);
    /// <summary>Try print <paramref name="arguments"/> into <paramref name="dst"/>.</summary>
    /// <param name="length">Number of characters written to <paramref name="dst"/>. If failed, the 0 is returned.</param>
    /// <returns>True if text was written, false if write failed.</returns>
    bool TryPrintTo(Span<char> dst, out int length, object?[]? arguments = null);
    /// <summary>Try estimate print length</summary>
    bool TryEstimatePrintLength(out int length, object?[]? arguments = null);
}

/// <summary>Root interface printable template.</summary>
public interface ITemplatePrintableBase
{
    /// <summary>Parameters in order of arguments and correspond to arguments and to <see cref="ITemplateParameterPart.ParameterIndex"/>.</summary>
    string?[] ParameterNames { get; set; }
}

.WithFormat(culture) adapts ITemplateFormatPrintable to ITemplatePrintable.

ITemplatePrintable printable = new TemplateText("Time is {0}.", TemplateFormat.Brace)
    .WithFormat(CultureInfo.CurrentCulture);

Printing

.Print(arguments) prints template string by placing arguments into placeholders.

// Create text without template format
ITemplatePrintable printable = new TemplateText("Time is {0}.", TemplateFormat.Brace).WithFormat(CultureInfo.CurrentCulture);
// Create arguments
object?[] arguments = { DateTime.Now };
// Print ok
string print = printable.Print(arguments);
// ""
WriteLine(print);

.Print(argumentMap) prints from a dictionary of arguments.

// Create text without template format
ITemplatePrintable printable = new TemplateText("Time is {0}.", TemplateFormat.Brace).WithFormat(CultureInfo.CurrentCulture);
// Create arguments
IDictionary<string, object?> argumentMap = new Dictionary<string, object?> { { "0", DateTime.Now } };
// Print ok
string print = printable.Print(argumentMap);
// ""
WriteLine(print);

Printable doesn't expose its inner template string. The implemenation may actually use different template strings, such as a localized or pluralized versions, depending on provided culture and argument values.

// Create localization
ILocalization localization = new Localization()
    .AddLine("", "Apple", "Detect", "You've got no apples.", "Unicode.CLDR", "count:cardinal:zero:en")
    .AddLine("", "Apple", "Detect", "You've got an apple.", "Unicode.CLDR", "count:cardinal:one:en")
    .AddLine("", "Apple", "Detect", "You've got {count} apples.", "Unicode.CLDR", "count:cardinal:other:en");
// Get printable
ITemplatePrintable printable = localization.LocalizableText["Apple"];
// "You have no apples."
WriteLine(printable.Print(new object?[] { 0 }));
// "You have an apple."
WriteLine(printable.Print(new object?[] { 1 }));
// "You have 3 apples."
WriteLine(printable.Print(new object?[] { 3 }));

.EstimatePrintLength(arguments) counts the number of characters and .PrintTo(span, culture, arg) writes to span. This is zero heap printing.

// Create template
ITemplatePrintable printable = new TemplateText("You have {0} apple(s).", TemplateFormat.Brace).WithFormat(CultureInfo.InvariantCulture);
// Create arguments
object[] arguments = { 3 };
// Estimate length
int length = printable.EstimatePrintLength(arguments);
// Allocate span
Span<char> span = length < 512 ? stackalloc char[length] : new char[length];
// Print to span
length = printable.PrintTo(span, arguments);
// Print to stdout, zero heap.
Console.Out.Write(span[..length]);

.EstimatePrintLength(argumentMap) estimates length from a dictionary of arguments.

// Create template
ITemplatePrintable printable = new TemplateText("You have {0} apple(s).", TemplateFormat.Brace).WithFormat(CultureInfo.InvariantCulture);
// Create arguments
IDictionary<string, object?> argumentMap = new Dictionary<string, object?> { { "0", 3 } };
// Estimate length
int length = printable.EstimatePrintLength(argumentMap);
// Allocate span
Span<char> span = length < 512 ? stackalloc char[length] : new char[length];
// Print to span
length = printable.PrintTo(span, argumentMap);
// Print to stdout, zero heap.
Console.Out.Write(span[..length]);

.TryPrintTo(span, arguments) attempts to print without possibility of throwing InvalidOperationException.

// Create template
ITemplatePrintable printable = new TemplateText("You have {0} apple(s).", TemplateFormat.Brace).WithFormat(CultureInfo.InvariantCulture);
// Create arguments
object[] arguments = { 3 };
// Estimate length
int length = printable.EstimatePrintLength(arguments);
// Allocate span
Span<char> span = length < 512 ? stackalloc char[length] : new char[length];
// Print to span
if (printable.TryPrintTo(span, out length, arguments))
    Console.Out.Write(span[..length]);

.TryPrintTo(span, argumentMap) attempts to print from a dictionary of arguments.

// Create template
ITemplatePrintable printable = new TemplateText("You have {0} apple(s).", TemplateFormat.Brace).WithFormat(CultureInfo.InvariantCulture);
// Create arguments
IDictionary<string, object?> argumentMap = new Dictionary<string, object?> { { "0", 3 } };
// Estimate length
int length = printable.EstimatePrintLength(argumentMap);
// Allocate span
Span<char> span = length < 512 ? stackalloc char[length] : new char[length];
// Print to span
if (printable.TryPrintTo(span, out length, argumentMap))
    Console.Out.Write(span[..length]);

.AppendTo(stringbuilder, arguments) appends to string builder.

// Create template
ITemplatePrintable printable = new TemplateText("You have {0} apple(s).", TemplateFormat.Brace).WithFormat(CultureInfo.InvariantCulture);
// Create arguments
object?[] arguments = { 3 };
// Create string builder
StringBuilder sb = new(1024);
// Append to string builder
printable.AppendTo(sb, arguments);
// Print
WriteLine(sb); // "You have 3 apple(s)."

.AppendTo(stringbuilder, argumentMap) appends from a dictionary of arguments.

// Create template
ITemplatePrintable printable = new TemplateText("You have {0} apple(s).", TemplateFormat.Brace).WithFormat(CultureInfo.InvariantCulture);
// Create arguments
object?[] arguments = { 3 };
// Create string builder
StringBuilder sb = new(1024);
// Append to string builder
printable.AppendTo(sb, arguments);
// Print
WriteLine(sb); // "You have 3 apple(s)."

.WriteTo(textwriter, arguments) writes to text writer.

// Create template
ITemplatePrintable printable = new TemplateText("You have {0} apple(s).", TemplateFormat.Brace).WithFormat(CultureInfo.InvariantCulture);
// Create arguments
object?[] arguments = { 3 };
// Assign text writer
TextWriter textWriter = Console.Out;
// Write to writer
printable.WriteTo(textWriter, arguments); // "You have 3 apple(s)."

.WriteTo(textwriter, argumentMap) writes from a dictionary of arguments.

// Create template
ITemplatePrintable printable = new TemplateText("You have {0} apple(s).", TemplateFormat.Brace).WithFormat(CultureInfo.InvariantCulture);
// Create arguments
IDictionary<string, object?> argumentMap = new Dictionary<string, object?> { { "0", 3 } };
// Assign text writer
TextWriter textWriter = Console.Out;
// Write to writer
printable.WriteTo(textWriter, argumentMap); // "You have 3 apple(s)."

Note

Thanks to C# 10 for Span, stackalloc, ISpanFormattable and MemoryPool which allow zero heap or near zero implementations.

// Create template
ITemplatePrintable printable = new TemplateText("You have {0} apple(s).", TemplateFormat.Brace).WithFormat(CultureInfo.InvariantCulture);
// Rent arguments
object[] arguments = ArrayPool<object>.Shared.Rent(1);
// Assign argument
arguments[0] = "3";
// Estimate length
int length = printable.EstimatePrintLength(arguments);
// Rent chars
char[] buffer = ArrayPool<char>.Shared.Rent(length);
// Print to buffer
length = printable.PrintTo(buffer.AsSpan(), arguments);
// Print to stdout, zero heap.
Console.Out.Write(buffer.AsSpan()[..length]);
// Return rentals
ArrayPool<object>.Shared.Return(arguments);
ArrayPool<char>.Shared.Return(buffer);            

Full Example

Full example

using System.Buffers;
using System.Globalization;
using System.Text;
using Avalanche.Localization;
using Avalanche.Template;
using static System.Console;

public class templateprintable
{
    public static void Run()
    {
        {
            // <01>
            ITemplatePrintable printable = new TemplateText("Time is {0}.", TemplateFormat.Brace)
                .WithFormat(CultureInfo.CurrentCulture);
            // </01>
        }
        {
            // <03>
            // Create text without template format
            ITemplatePrintable printable = new TemplateText("Time is {0}.", TemplateFormat.Brace).WithFormat(CultureInfo.CurrentCulture);
            // Create arguments
            object?[] arguments = { DateTime.Now };
            // Print ok
            string print = printable.Print(arguments);
            // ""
            WriteLine(print);
            // </03>
        }
        {
            // <03B>
            // Create text without template format
            ITemplatePrintable printable = new TemplateText("Time is {0}.", TemplateFormat.Brace).WithFormat(CultureInfo.CurrentCulture);
            // Create arguments
            IDictionary<string, object?> argumentMap = new Dictionary<string, object?> { { "0", DateTime.Now } };
            // Print ok
            string print = printable.Print(argumentMap);
            // ""
            WriteLine(print);
            // </03B>
        }
        {
            // <04>
            // Create localization
            ILocalization localization = new Localization()
                .AddLine("", "Apple", "Detect", "You've got no apples.", "Unicode.CLDR", "count:cardinal:zero:en")
                .AddLine("", "Apple", "Detect", "You've got an apple.", "Unicode.CLDR", "count:cardinal:one:en")
                .AddLine("", "Apple", "Detect", "You've got {count} apples.", "Unicode.CLDR", "count:cardinal:other:en");
            // Get printable
            ITemplatePrintable printable = localization.LocalizableText["Apple"];
            // "You have no apples."
            WriteLine(printable.Print(new object?[] { 0 }));
            // "You have an apple."
            WriteLine(printable.Print(new object?[] { 1 }));
            // "You have 3 apples."
            WriteLine(printable.Print(new object?[] { 3 }));
            // </04>
        }

        {
            // <05>
            // Create template
            ITemplatePrintable printable = new TemplateText("You have {0} apple(s).", TemplateFormat.Brace).WithFormat(CultureInfo.InvariantCulture);
            // Create arguments
            object[] arguments = { 3 };
            // Estimate length
            int length = printable.EstimatePrintLength(arguments);
            // Allocate span
            Span<char> span = length < 512 ? stackalloc char[length] : new char[length];
            // Print to span
            length = printable.PrintTo(span, arguments);
            // Print to stdout, zero heap.
            Console.Out.Write(span[..length]);
            // </05>
            WriteLine();
        }
        {
            // <05B>
            // Create template
            ITemplatePrintable printable = new TemplateText("You have {0} apple(s).", TemplateFormat.Brace).WithFormat(CultureInfo.InvariantCulture);
            // Create arguments
            IDictionary<string, object?> argumentMap = new Dictionary<string, object?> { { "0", 3 } };
            // Estimate length
            int length = printable.EstimatePrintLength(argumentMap);
            // Allocate span
            Span<char> span = length < 512 ? stackalloc char[length] : new char[length];
            // Print to span
            length = printable.PrintTo(span, argumentMap);
            // Print to stdout, zero heap.
            Console.Out.Write(span[..length]);
            // </05B>
            WriteLine();
        }

        {
            // <06>
            // Create template
            ITemplatePrintable printable = new TemplateText("You have {0} apple(s).", TemplateFormat.Brace).WithFormat(CultureInfo.InvariantCulture);
            // Create arguments
            object[] arguments = { 3 };
            // Estimate length
            int length = printable.EstimatePrintLength(arguments);
            // Allocate span
            Span<char> span = length < 512 ? stackalloc char[length] : new char[length];
            // Print to span
            if (printable.TryPrintTo(span, out length, arguments))
                Console.Out.Write(span[..length]);
            // </06>
            WriteLine();
        }
        {
            // <06B>
            // Create template
            ITemplatePrintable printable = new TemplateText("You have {0} apple(s).", TemplateFormat.Brace).WithFormat(CultureInfo.InvariantCulture);
            // Create arguments
            IDictionary<string, object?> argumentMap = new Dictionary<string, object?> { { "0", 3 } };
            // Estimate length
            int length = printable.EstimatePrintLength(argumentMap);
            // Allocate span
            Span<char> span = length < 512 ? stackalloc char[length] : new char[length];
            // Print to span
            if (printable.TryPrintTo(span, out length, argumentMap))
                Console.Out.Write(span[..length]);
            // </06B>
            WriteLine();
        }

        {
            // <11>
            // Create template
            ITemplatePrintable printable = new TemplateText("You have {0} apple(s).", TemplateFormat.Brace).WithFormat(CultureInfo.InvariantCulture);
            // Create arguments
            object?[] arguments = { 3 };
            // Create string builder
            StringBuilder sb = new(1024);
            // Append to string builder
            printable.AppendTo(sb, arguments);
            // Print
            WriteLine(sb); // "You have 3 apple(s)."
            // </11>
        }
        {
            // <11B>
            // Create template
            ITemplatePrintable printable = new TemplateText("You have {0} apple(s).", TemplateFormat.Brace).WithFormat(CultureInfo.InvariantCulture);
            // Create arguments
            IDictionary<string, object?> argumentMap = new Dictionary<string, object?> { { "0", 3 } };
            // Create string builder
            StringBuilder sb = new(1024);
            // Append to string builder
            printable.AppendTo(sb, argumentMap);
            // Print
            WriteLine(sb); // "You have 3 apple(s)."
            // </11B>
        }

        {
            // <13>
            // Create template
            ITemplatePrintable printable = new TemplateText("You have {0} apple(s).", TemplateFormat.Brace).WithFormat(CultureInfo.InvariantCulture);
            // Create arguments
            object?[] arguments = { 3 };
            // Assign text writer
            TextWriter textWriter = Console.Out;
            // Write to writer
            printable.WriteTo(textWriter, arguments); // "You have 3 apple(s)."
            // </13>
            WriteLine();
        }
        {
            // <13B>
            // Create template
            ITemplatePrintable printable = new TemplateText("You have {0} apple(s).", TemplateFormat.Brace).WithFormat(CultureInfo.InvariantCulture);
            // Create arguments
            IDictionary<string, object?> argumentMap = new Dictionary<string, object?> { { "0", 3 } };
            // Assign text writer
            TextWriter textWriter = Console.Out;
            // Write to writer
            printable.WriteTo(textWriter, argumentMap); // "You have 3 apple(s)."
            // </13B>
            WriteLine();
        }

        {
            // <20>
            // Create template
            ITemplatePrintable printable = new TemplateText("You have {0} apple(s).", TemplateFormat.Brace).WithFormat(CultureInfo.InvariantCulture);
            // Rent arguments
            object[] arguments = ArrayPool<object>.Shared.Rent(1);
            // Assign argument
            arguments[0] = "3";
            // Estimate length
            int length = printable.EstimatePrintLength(arguments);
            // Rent chars
            char[] buffer = ArrayPool<char>.Shared.Rent(length);
            // Print to buffer
            length = printable.PrintTo(buffer.AsSpan(), arguments);
            // Print to stdout, zero heap.
            Console.Out.Write(buffer.AsSpan()[..length]);
            // Return rentals
            ArrayPool<object>.Shared.Return(arguments);
            ArrayPool<char>.Shared.Return(buffer);            
            // </20>
            WriteLine();
        }
    }
}