1 files changed, 129 insertions, 0 deletions
diff --git a/Compiler/FunctionReference.cs b/Compiler/FunctionReference.cs
new file mode 100644
index 0000000..cf120ad
--- /dev/null
+++ b/Compiler/FunctionReference.cs
@@ -0,0 +1,129 @@
+namespace Q1.Compiler;
+
+using System.Reflection.Metadata;
+using System.Text;
+
+public class FunctionReference
+{
+    // TODO: Implement return type
+    public string                 Name;
+    public string                 Type;
+    public List<FunctionOverload> Overloads = new();
+
+    public FunctionReference(string name, string type)
+    {
+        this.Type = type;
+        this.Name = name;
+    }
+
+    public string GetBranchName(FunctionOverload overload)
+    {
+        List<(string paramName, string paramType)> parameters = overload
+            .ParameterNames
+            .Zip(overload.ParameterTypes)
+            .ToList();
+
+        StringBuilder branchName = new();
+        branchName.Append($"_{this.Name}");
+
+        if (parameters.Count > 0)
+        {
+            branchName.Append($"_{string.Join("__", parameters
+                .Select(x => $"{x.paramType}_{x.paramName}"))}");
+        }
+
+        return branchName.ToString();
+    }
+
+    public string GetBranchFriendlyName(FunctionOverload overload)
+    {
+        List<(string paramName, string paramType)> parameters = overload
+            .ParameterNames
+            .Zip(overload.ParameterTypes)
+            .ToList();
+
+        StringBuilder branchName = new();
+        branchName.Append($"{this.Type} {this.Name}");
+        branchName.Append("(");
+
+        branchName.Append(string.Join(", ", parameters
+            .Select(x => $"{x.paramType} {x.paramName}")));
+
+        branchName.Append(")");
+
+        return branchName.ToString();
+    }
+
+    public FunctionOverload CreateOverloadWithBody(List<string> parameterNames, List<string> parameterTypes)
+    {
+        FunctionOverload? existingOverload = this.Overloads
+            .FirstOrDefault(x => x.ParamsMatch(parameterNames, parameterTypes));
+
+        if (existingOverload != null)
+        {
+            if (existingOverload.BodyImplemented)
+                throw new CompilerException($"Cannot define another overload for {this.Name},"
+                                            + $" as one with an identical signature and body already exists.");
+
+            existingOverload.BodyImplemented = true;
+            return existingOverload;
+        }
+        else
+        {
+            FunctionOverload newOverload = new(parameterNames, parameterTypes, true);
+            this.Overloads.Add(newOverload);
+            return newOverload;
+        }
+    }
+
+    public FunctionOverload CreateOverloadWithoutBody(List<string> parameterNames, List<string> parameterTypes)
+    {
+        FunctionOverload? existingOverload = this.Overloads
+            .FirstOrDefault(x => x.ParamsMatch(parameterNames, parameterTypes));
+
+        if (existingOverload != null)
+        {
+            if (!existingOverload.BodyImplemented)
+                throw new CompilerException($"Cannot prototype another overload for {this.Name},"
+                                            + $" as one with an identical signature already exists.");
+            return existingOverload;
+        }
+        else
+        {
+            FunctionOverload newOverload = new(parameterNames, parameterTypes, false);
+            this.Overloads.Add(newOverload);
+            return newOverload;
+        }
+    }
+    public FunctionOverload GetOverload(int paramsCount)
+    {
+        FunctionOverload? overload = this.Overloads
+            .FirstOrDefault(x => x.ParameterTypes.Count == paramsCount);
+
+        if (overload != null)
+            return overload;
+
+        throw new CompilerException($"Overload for {this.Name} with {paramsCount} arguments could not be found.");
+    }
+}
+
+public class FunctionOverload
+{
+    // TODO: Implement return type
+    public List<string> ParameterTypes;
+    public List<string> ParameterNames;
+    public bool         BodyImplemented;
+
+    public FunctionOverload(List<string> parameterNames, List<string> parameterTypes, bool bodyImplemented)
+    {
+        this.ParameterTypes  = parameterTypes;
+        this.ParameterNames  = parameterNames;
+        this.BodyImplemented = bodyImplemented;
+    }
+
+    public bool ParamsMatch(List<string> parameterNames, List<string> parameterTypes)
+    {
+        return this.ParameterNames.SequenceEqual(parameterNames)
+               && this.ParameterTypes.SequenceEqual(parameterTypes);
+    }
+}
+\ No newline at end of file