Add 'toBool' conversion function

Added a new function 'toBool' to convert values into boolean type. The changes include adding a new class for this function, adding it to the application scope, and explaining its functionality in the Wiki page. Also added the test cases for the new function. The function is designed to interpret numbers, strings, lists, and other data types in a way that makes sense in a boolean context. This provides a more intuitive way for users to perform boolean operations with different data types.

StepLang.Tests/Examples/conversions.step.out

@@ -8,3 +8,14 @@ null
 170
 10
 255
+False
+False
+True
+False
+True
+True
+False
+False
+True
+True
+False

StepLang.Wiki/Functions/ToBool.md

@@ -0,0 +1,43 @@
+# Description
+
+The `toBool` function converts a value to a boolean value.
+
+# Syntax
+
+```
+toBool(any value)
+```
+
+- `value` is the value to convert to a boolean value.
+
+# Remarks
+
+- The function returns `true` if the value is truthy (true-like), `false` otherwise.  
+  Whether or not a value is truthy can be determined using the following table:
+
+  | Value Type | Truthy                               | Falsy     |
+  |------------|--------------------------------------|-----------|
+  | `bool`     | `true`                               | `false`   |
+  | `number`   | `> 0`                                | `<= 0`    |
+  | `string`   | `"true"` (case insensitive) or `"1"` | otherwise |
+  | `list`     | if not empty                         | otherwise |
+  | `map`      | if not empty                         | otherwise |
+  | `null`     | never                                | always    |
+  | `void`     | never                                | always    |
+  | `function` | always                               | never     |
+
+# Examples
+
+```step
+println(toBool(""))              // False
+println(toBool("this is falsy")) // False
+println(toBool("true"))          // True
+println(toBool("false"))         // False
+println(toBool("True"))          // True
+println(toBool("1"))             // True
+println(toBool("0"))             // False
+println(toBool(0))               // False
+println(toBool(1))               // True
+println(toBool(2))               // True
+println(toBool(-1))              // False
+```

StepLang/Examples/conversions.step

@@ -9,3 +9,15 @@ println(toNumber("FF", 16))
 println(toNumber("aa", 16))
 println(toNumber("1010", 2))
 println(toNumber("377", 8))
+
+println(toBool(""))
+println(toBool("this is falsy"))
+println(toBool("true"))
+println(toBool("false"))
+println(toBool("True"))
+println(toBool("1"))
+println(toBool("0"))
+println(toBool(0))
+println(toBool(1))
+println(toBool(2))
+println(toBool(-1))

StepLang/Framework/Conversion/ToBoolFunction.cs

@@ -0,0 +1,39 @@
+using StepLang.Interpreting;
+using StepLang.Parsing.Expressions;
+
+namespace StepLang.Framework.Conversion;
+
+public class ToBoolFunction : NativeFunction
+{
+    public const string Identifier = "toBool";
+
+    public override async Task<ExpressionResult> EvaluateAsync(Interpreter interpreter, IReadOnlyList<Expression> arguments, CancellationToken cancellationToken = default)
+    {
+        CheckArgumentCount(arguments, 1);
+
+        var value = await arguments.Single().EvaluateAsync(interpreter, cancellationToken);
+
+        var result = value switch
+        {
+            StringResult stringResult when string.IsNullOrWhiteSpace(stringResult.Value) => false,
+            StringResult stringResult => stringResult.Value.ToUpperInvariant() switch
+            {
+                "TRUE" => true,
+                "1" => true,
+                _ => false,
+            },
+            NumberResult numberResult => numberResult.Value > 0,
+            BoolResult boolResult => boolResult.Value,
+            ListResult listResult => listResult.Value.Count > 0,
+            MapResult mapResult => mapResult.Value.Count > 0,
+            FunctionResult => true,
+            NullResult => false,
+            VoidResult => false,
+            _ => throw new NotImplementedException(),
+        };
+
+        return new BoolResult(result);
+    }
+
+    protected override string DebugParamsString => "any value";
+}

StepLang/Interpreting/Scope.cs

@@ -53,6 +53,7 @@ private Scope()
         SetVariable(ToStringFunction.Identifier, new FunctionResult(new ToStringFunction()));
         SetVariable(ToRadixFunction.Identifier, new FunctionResult(new ToRadixFunction()));
         SetVariable(ToNumberFunction.Identifier, new FunctionResult(new ToNumberFunction()));
+        SetVariable(ToBoolFunction.Identifier, new FunctionResult(new ToBoolFunction()));
 
         // other functions
         SetVariable(FileExistsFunction.Identifier, new FunctionResult(new FileExistsFunction()));