From b97134a15585fef42c50e3faa7b033991700eaa3 Mon Sep 17 00:00:00 2001
From: Ludovic 'Archivist' Lagouardette <ludovic@nekoit.xyz>
Date: Wed, 8 Sep 2021 11:56:13 +0200
Subject: [PATCH] While loops

---
 Functions/Add.cs  | 14 ++++++++++++++
 Parser.cs         | 43 ++++++++++++++++++++++++++++++++++++++++---
 Program.cs        |  1 +
 SuperBASIC.csproj |  4 ++++
 Test.basic        | 25 +++++++++++--------------
 5 files changed, 70 insertions(+), 17 deletions(-)
 create mode 100644 Functions/Add.cs

diff --git a/Functions/Add.cs b/Functions/Add.cs
new file mode 100644
index 0000000..8a13eca
--- /dev/null
+++ b/Functions/Add.cs
@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace SuperBASIC.Functions
+{
+	class Add : IFunction
+	{
+		float IFunction.Apply(List<BasicNumber> arguments)
+		{
+			return arguments[0] + arguments[1];
+		}
+	}
+}
diff --git a/Parser.cs b/Parser.cs
index b83ad3f..0a560f4 100644
--- a/Parser.cs
+++ b/Parser.cs
@@ -230,9 +230,9 @@ namespace SuperBASIC
 						{
 							//Case 2: update the JZ
 							c.bytecode[label.index + 2] = new BasicNumber(runtime, (float)c.bytecode.Count);
-						} 
-						else 
-						{ 
+						}
+						else
+						{
 							int lineIndex = 0;
 							foreach (int cnt in lineSpans.GetRange(0, idx + 1)) lineIndex += cnt;
 							throw new ParseException($"Orphaned ENDIF\n\tat line {lineIndex}");
@@ -245,6 +245,43 @@ namespace SuperBASIC
 							throw new ParseException($"Orphaned ENDIF despite THEN\n\tat line {lineIndex}");
 						}
 						break;
+					case "WHILE":
+						// Role: manages the expression
+						// 1. Deal with expression
+						label.ctrl = Controls.While;
+						label.index = c.bytecode.Count;
+						labelStack.Push(label);
+						ParseExpression(c, components[1..], idx, lineSpans);
+						// 2. Adds the label to update the destination
+						label.ctrl = Controls.Wend;
+						label.index = c.bytecode.Count;
+						labelStack.Push(label);
+						// 3. Adds the jumper
+						c.bytecode.Add(new BasicNumber(runtime, library.nameResolution["JZ"]));
+						c.bytecode.Add(new BasicNumber(runtime));
+						c.bytecode.Add(new BasicNumber(runtime, 0f));
+						break;
+					case "WEND":
+						//Role: Destination if depending on what is skipped
+						var labelA = labelStack.Pop();
+						if (labelA.ctrl == Controls.Wend)
+						{
+
+							label = labelStack.Pop();
+							if (label.ctrl == Controls.While)
+							{
+								c.bytecode.Add(new BasicNumber(runtime, library.nameResolution["GOTO"]));
+								c.bytecode.Add(new BasicNumber(runtime, (float)label.index));
+								c.bytecode[labelA.index + 2] = new BasicNumber(runtime, (float)c.bytecode.Count);
+							}
+						}
+						else
+						{
+							int lineIndex = 0;
+							foreach (int cnt in lineSpans.GetRange(0, idx + 1)) lineIndex += cnt;
+							throw new ParseException($"Orphaned WEND\n\tat line {lineIndex}");
+						}
+						break;
 					default:
 						ParseExpression(c, components, idx, lineSpans);
 					break;
diff --git a/Program.cs b/Program.cs
index cda8602..09780aa 100644
--- a/Program.cs
+++ b/Program.cs
@@ -16,6 +16,7 @@ namespace SuperBASIC
 #endif
 				lib.AddFunction(new Functions.Print(), 1, "PRINT");
 				lib.AddFunction(new Functions.Multiply(), 2, "MULTIPLY");
+				lib.AddFunction(new Functions.Add(), 2, "ADD");
 				lib.AddFunction(new Functions.Compare(), 2, "COMPARE");
 				lib.AddFunction(new Functions.JumpZero(), 2, "JZ");
 				lib.AddFunction(new Functions.Goto(), 1, "GOTO");
diff --git a/SuperBASIC.csproj b/SuperBASIC.csproj
index fdb69aa..e753f19 100644
--- a/SuperBASIC.csproj
+++ b/SuperBASIC.csproj
@@ -5,6 +5,10 @@
     <TargetFramework>netcoreapp3.1</TargetFramework>
   </PropertyGroup>
 
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|AnyCPU'">
+    <DefineConstants>TRACE;MEMORY</DefineConstants>
+  </PropertyGroup>
+
   <ItemGroup>
     <None Update="Test.basic">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
diff --git a/Test.basic b/Test.basic
index 1b16704..5c768cd 100644
--- a/Test.basic
+++ b/Test.basic
@@ -1,14 +1,11 @@
-EULER
-MULTIPLY $ $
-
-IF COMPARE $ 7.3890557
-THEN
-PRINT 25
-GOTO end
-ELSE
-PRINT 10
-ENDIF
-LABEL loop
-PRINT 50
-GOTO loop
-LABEL end
\ No newline at end of file
+MEMSTORE 1 0
+MEMSTORE 0 10
+WHILE MEMLOAD 0
+MEMLOAD 0
+ADD $ -1
+MEMSTORE 0 $
+MEMLOAD 1
+ADD $ 1
+MEMSTORE 1 $
+PRINT M1
+WEND
\ No newline at end of file