Begin implementing Bytes in the Elm compiler and kernel libraries

+ Expand the Elm value model to support values representing sequences of bytes corresponding to the `Bytes.Bytes` type.
+ Begin implementing the `Bytes.Encode`  Elm kernel module.
+ Begin to implement the `Bytes.Decode`  Elm kernel module.
+ Automate tests using the first encoding and decoding implementations.

implement/Pine.Core/ElmInteractive/ElmValue.cs

@@ -21,6 +21,7 @@ type ElmValue
         | ElmString String
         | ElmTag String (List ElmValue)
         | ElmRecord (List ( String, ElmValue ))
+        | ElmBytes Bytes
         | ElmFloat BigInt.BigInt BigInt.BigInt
         | ElmInternal String
 
@@ -37,6 +38,8 @@ override public string ToString() =>
 
     public const string ElmRecordTypeTagName = "Elm_Record";
 
+    public const string ElmBytesTypeTagName = "Elm_Bytes";
+
     public const string ElmStringTypeTagName = "String";
 
     public const string ElmSetTypeTagName = "Set_elm_builtin";
@@ -50,6 +53,9 @@ override public string ToString() =>
     public static readonly PineValue ElmRecordTypeTagNameAsValue =
         PineValueAsString.ValueFromString(ElmRecordTypeTagName);
 
+    public static readonly PineValue ElmBytesTypeTagNameAsValue =
+        PineValueAsString.ValueFromString(ElmBytesTypeTagName);
+
     public static readonly PineValue ElmStringTypeTagNameAsValue =
         PineValueAsString.ValueFromString(ElmStringTypeTagName);
 
@@ -364,6 +370,35 @@ public override string ToString() =>
             Fields.FirstOrDefault(field => field.FieldName == fieldName).Value;
     }
 
+    /// <summary>
+    /// Elm Bytes type from https://package.elm-lang.org/packages/elm/bytes/latest/
+    /// </summary>
+    public record ElmBytes(ReadOnlyMemory<byte> Value)
+        : ElmValue
+    {
+        /// <summary>
+        /// The number of contained nodes is always zero for the 'Bytes' variant.
+        /// </summary>
+        public override int ContainedNodesCount { get; } = 0;
+
+
+        /// <inheritdoc/>
+        public virtual bool Equals(ElmBytes? otherBytes)
+        {
+            if (otherBytes is null)
+                return false;
+
+            if (Value.Length != otherBytes.Value.Length)
+                return false;
+
+            return Value.Span.SequenceEqual(otherBytes.Value.Span);
+        }
+
+        /// <inheritdoc/>
+        public override int GetHashCode() =>
+            Value.GetHashCode();
+    }
+
     /// <summary>
     /// The Elm compiler included with Pine models the 'Float' type from Elm as a rational number,
     /// expressed as the quotient or fraction ⁠of two integers, a numerator and a denominator.
@@ -503,6 +538,9 @@ public static (string expressionString, bool needsParens) RenderAsElmExpression(
                 ElmTag tag =>
                 ElmTagAsExpression(tag.TagName, tag.Arguments),
 
+                ElmBytes bytes =>
+                ("<" + bytes.Value.Length + " bytes>", needsParens: false),
+
                 ElmFloat elmFloat =>
                 (Convert.ToString(
                     (double)elmFloat.Numerator / (double)elmFloat.Denominator,

implement/Pine.Core/ElmInteractive/ElmValueEncoding.cs

@@ -143,6 +143,26 @@ public static Result<string, ElmValue> PineListValueAsElmValue(PineValue.ListVal
                     }
                 }
 
+                {
+                    // case of Bytes.Bytes
+
+                    if (listValue.Elements[0] == ElmValue.ElmBytesTypeTagNameAsValue)
+                    {
+                        var tagArgumentsValue = listValue.Elements[1];
+
+                        if (tagArgumentsValue is not PineValue.ListValue tagArgumentsList)
+                            return "Failed to convert value under Bytes tag: Expected a list of tag arguments";
+
+                        if (tagArgumentsList.Elements.Count is not 1)
+                            return "Failed to convert value under Bytes tag: Expected a list of tag arguments with single item";
+
+                        if (tagArgumentsList.Elements[0] is not PineValue.BlobValue blobValue)
+                            return "Failed to convert value under Bytes tag: Expected blob value in tag argument";
+
+                        return new ElmValue.ElmBytes(blobValue.Bytes);
+                    }
+                }
+
                 {
                     // Optimize for the case of an Elm Float.
 
@@ -332,6 +352,7 @@ public static Result<string, ElmValue> PineListValueAsElmValue(PineValue.ListVal
                     recordFields[i] = (fieldName.Value, fieldValueOk.Value);
                     continue;
                 }
+
                 return "Failed decoding field value: " + fieldValueResult;
             }
 
@@ -450,6 +471,11 @@ [.. elmList.Elements.Select(item => ElmValueAsPineValue(item, reusableEncoding))
                 ElmRecordAsPineValue(
                     [.. elmRecord.Fields.Select(field => (field.FieldName, ElmValueAsPineValue(field.Value, reusableEncoding)))]),
 
+                ElmValue.ElmBytes elmBytes =>
+                PineValue.List(
+                    [ElmValue.ElmBytesTypeTagNameAsValue,
+                    PineValue.List([PineValue.Blob(elmBytes.Value)])]),
+
                 ElmValue.ElmFloat elmFloat =>
                 PineValue.List(
                     [ElmValue.ElmFloatTypeTagNameAsValue,

implement/Pine.Core/PopularValues.cs

@@ -24,6 +24,7 @@ from c2 in Enumerable.Range(0, 128)
     private static IEnumerable<string> PopularStringsSource =>
     [
         "Elm_Record",
+        "Elm_Bytes",
 
         "Basics",
         "List",

implement/pine/ElmTime/compile-elm-program/src/ElmCompiler.elm

@@ -9,6 +9,7 @@ module ElmCompiler exposing
     , compilationAndEmitStackFromModulesInCompilation
     , compileElmSyntaxExpression
     , compileElmSyntaxFunction
+    , elmBytesTypeTagNameAsValue
     , elmFloatTypeTagName
     , elmRecordTypeTagName
     , elmRecordTypeTagNameAsValue
@@ -142,6 +143,16 @@ elmRecordTypeTagNameAsValue =
     Pine.valueFromString elmRecordTypeTagName
 
 
+elmBytesTypeTagName : String
+elmBytesTypeTagName =
+    "Elm_Bytes"
+
+
+elmBytesTypeTagNameAsValue : Pine.Value
+elmBytesTypeTagNameAsValue =
+    Pine.valueFromString elmBytesTypeTagName
+
+
 elmFloatTypeTagName : String
 elmFloatTypeTagName =
     "Elm_Float"