Flee

2025-10-08 09:49:37 +08:00
commit 284e764345
99 changed files with 21742 additions and 0 deletions
--- a/ExpressionElements/Conditional.cs
+++ b/ExpressionElements/Conditional.cs
@@ -0,0 +1,75 @@
+using System.Reflection.Emit;
+using Flee.ExpressionElements.Base;
+using Flee.InternalTypes;
+using Flee.PublicTypes;
+using Flee.Resources;
+
+namespace Flee.ExpressionElements
+{
+    internal class ConditionalElement : ExpressionElement
+    {
+        private readonly ExpressionElement _myCondition;
+        private readonly ExpressionElement _myWhenTrue;
+        private readonly ExpressionElement _myWhenFalse;
+        private readonly Type _myResultType;
+        public ConditionalElement(ExpressionElement condition, ExpressionElement whenTrue, ExpressionElement whenFalse)
+        {
+            _myCondition = condition;
+            _myWhenTrue = whenTrue;
+            _myWhenFalse = whenFalse;
+
+            if ((!object.ReferenceEquals(_myCondition.ResultType, typeof(bool))))
+            {
+                base.ThrowCompileException(CompileErrorResourceKeys.FirstArgNotBoolean, CompileExceptionReason.TypeMismatch);
+            }
+
+            // The result type is the type that is common to the true/false operands
+            if (ImplicitConverter.EmitImplicitConvert(_myWhenFalse.ResultType, _myWhenTrue.ResultType, null) == true)
+            {
+                _myResultType = _myWhenTrue.ResultType;
+            }
+            else if (ImplicitConverter.EmitImplicitConvert(_myWhenTrue.ResultType, _myWhenFalse.ResultType, null) == true)
+            {
+                _myResultType = _myWhenFalse.ResultType;
+            }
+            else
+            {
+                base.ThrowCompileException(CompileErrorResourceKeys.NeitherArgIsConvertibleToTheOther, CompileExceptionReason.TypeMismatch, _myWhenTrue.ResultType.Name, _myWhenFalse.ResultType.Name);
+            }
+        }
+
+        public override void Emit(FleeILGenerator ilg, IServiceProvider services)
+        {
+            this.EmitConditional(ilg, services);
+        }
+
+        private void EmitConditional(FleeILGenerator ilg, IServiceProvider services)
+        {
+            Label falseLabel = ilg.DefineLabel();
+            Label endLabel = ilg.DefineLabel();
+
+            // Emit the condition
+            _myCondition.Emit(ilg, services);
+
+            // On false go to the false operand
+            ilg.EmitBranchFalse(falseLabel);
+
+            // Emit the true operand
+            _myWhenTrue.Emit(ilg, services);
+            ImplicitConverter.EmitImplicitConvert(_myWhenTrue.ResultType, _myResultType, ilg);
+
+            // Jump to end
+            ilg.EmitBranch(endLabel);
+
+            ilg.MarkLabel(falseLabel);
+
+            // Emit the false operand
+            _myWhenFalse.Emit(ilg, services);
+            ImplicitConverter.EmitImplicitConvert(_myWhenFalse.ResultType, _myResultType, ilg);
+            // Fall through to end
+            ilg.MarkLabel(endLabel);
+        }
+
+        public override System.Type ResultType => _myResultType;
+    }
+}