添加对while-do语句的支持 (#77)

Co-authored-by: jackfiled <xcrenchangjun@outlook.com>
Reviewed-on: PostGuard/Canon#77
Co-authored-by: ichirinko <1621543655@qq.com>
Co-committed-by: ichirinko <1621543655@qq.com>

Canon.Core/Enums/SemanticEnums.cs

@@ -65,7 +65,8 @@ public enum KeywordType
     And,
     Or,
     True,
-    False
+    False,
+    While
 }
 
 public enum OperatorType

Canon.Core/GrammarParser/PascalGrammar.cs

@@ -348,6 +348,7 @@ public static class PascalGrammar
             //           | CompoundStatement
             //           | if Expression then Statement ElsePart
             //           | for id AssignOp Expression to Expression do Statement
+            //           | while Expression do Statement
             // 注意这里 read 和 write 作为普通的函数调用处理了
             // 因此下面并没有单独声明
             new NonTerminator(NonTerminatorType.Statement), [
@@ -387,6 +388,13 @@ public static class PascalGrammar
                     new NonTerminator(NonTerminatorType.Expression),
                     new Terminator(KeywordType.Do),
                     new NonTerminator(NonTerminatorType.Statement)
+                ],
+                [
+                    // while Expression do Statement
+                    new Terminator(KeywordType.While),
+                    new NonTerminator(NonTerminatorType.Expression),
+                    new Terminator(KeywordType.Do),
+                    new NonTerminator(NonTerminatorType.Statement)
                 ]
             ]
         },

Canon.Core/LexicalParser/LexRules.cs

@@ -33,7 +33,8 @@ public static class LexRules
             { "and", KeywordType.And },
             { "or", KeywordType.Or },
             { "true", KeywordType.True },
-            { "false", KeywordType.False }
+            { "false", KeywordType.False },
+            { "while", KeywordType.While }
         };
 
     public static bool GetKeywordTypeByKeywprd(string keyword, out KeywordType type)

Canon.Core/SemanticParser/CodeGeneratorVisitor.cs

@@ -294,6 +294,18 @@ public class CodeGeneratorVisitor : TypeCheckVisitor
         };
     }
 
+    public override void PreVisit(Expression expression)
+    {
+        base.PreVisit(expression);
+
+        if (expression.IsWhileCondition)
+        {
+            GenerateWhileLabel();
+            Builder.AddLine($"""
+                             {_whileBeginLabels.Peek()}:;
+                             """);
+        }
+    }
     public override void PostVisit(Expression expression)
     {
         base.PostVisit(expression);
@@ -333,6 +345,11 @@ public class CodeGeneratorVisitor : TypeCheckVisitor
         {
             _forEndConditions.Push(expression.VariableName);
         }
+
+        if (expression.IsWhileCondition)
+        {
+            _whileConditionNames.Push(expression.VariableName);
+        }
     }
 
 
@@ -386,6 +403,21 @@ public class CodeGeneratorVisitor : TypeCheckVisitor
     /// </summary>
     private readonly Stack<string> _forEndLabels = new();
 
+    /// <summary>
+    /// WHILE语句条件变量的标签
+    /// </summary>
+    private readonly Stack<string> _whileConditionNames = new();
+
+    /// <summary>
+    /// WHILE语句开始的标签
+    /// </summary>
+    private readonly Stack<string> _whileBeginLabels = new();
+
+    /// <summary>
+    /// WHILE语句结束的标签
+    /// </summary>
+    private readonly Stack<string> _whileEndLabels = new();
+
     public override void PreVisit(Statement statement)
     {
         base.PreVisit(statement);
@@ -396,8 +428,15 @@ public class CodeGeneratorVisitor : TypeCheckVisitor
         {
             e.Begin.IsForConditionBegin = true;
             e.End.IsForConditionEnd = true;
+            e.Do.IsForNode = true;
             _forVariables.Push(e.Iterator.IdentifierName);
         };
+
+        statement.OnWhileGenerator += (_, e) =>
+        {
+            e.Do.IsWhileNode = true;
+            e.Condition.IsWhileCondition = true;
+        };
     }
 
     public override void PostVisit(Statement statement)
@@ -434,6 +473,17 @@ public class CodeGeneratorVisitor : TypeCheckVisitor
             _forBeginConditions.Pop();
             _forEndConditions.Pop();
         };
+
+        statement.OnWhileGenerator += (_, _) =>
+        {
+            Builder.AddLine($"""
+                             goto {_whileBeginLabels.Peek()};
+                             {_whileEndLabels.Peek()}:;
+                             """);
+            _whileBeginLabels.Pop();
+            _whileEndLabels.Pop();
+            _whileConditionNames.Pop();
+        };
     }
 
     public override void PreVisit(ElsePart elsePart)
@@ -605,6 +655,8 @@ public class CodeGeneratorVisitor : TypeCheckVisitor
                                      """);
                     break;
                 case KeywordType.Do:
+                    if (terminatedSyntaxNode.IsForNode)
+                    {
                         Builder.AddLine($"""
                                          if ({_forVariables.Peek()} <= {_forEndConditions.Peek()})
                                              goto {_forLabels.Peek()};
@@ -612,6 +664,17 @@ public class CodeGeneratorVisitor : TypeCheckVisitor
                                              goto {_forEndLabels.Peek()};
                                          {_forLabels.Peek()}:;
                                          """);
+                    }
+
+                    if (terminatedSyntaxNode.IsWhileNode)
+                    {
+                        // GenerateWhileLabel();
+                        Builder.AddLine($"""
+                                         if (!{_whileConditionNames.Peek()})
+                                             goto {_whileEndLabels.Peek()};
+                                         """);
+                    }
+
                     break;
             }
         }
@@ -881,4 +944,16 @@ public class CodeGeneratorVisitor : TypeCheckVisitor
 
         _labelCount += 1;
     }
+
+    /// <summary>
+    /// 产生WHILE语句中的标签
+    /// </summary>
+    private void GenerateWhileLabel()
+    {
+        _whileBeginLabels.Push($"while_{_labelCount}");
+        _whileConditionNames.Push($"while_condition_{_labelCount}");
+        _whileEndLabels.Push($"while_end_{_labelCount}");
+
+        _labelCount += 1;
+    }
 }

Canon.Core/SemanticParser/TypeCheckVisitor.cs

@@ -478,6 +478,18 @@ public class TypeCheckVisitor(ICompilerLogger? logger = null) : SyntaxNodeVisito
                     e.Condition.VariableType.ToString());
             }
         };
+
+        // statement -> while Expression do Statement
+        statement.OnWhileGenerator += (_, e) =>
+        {
+            // 条件是否为Boolean
+            if (e.Condition.VariableType != PascalBasicType.Boolean)
+            {
+                IsError = true;
+                logger?.LogError("Expect '{}' but '{}'.", PascalBasicType.Boolean.TypeName,
+                    e.Condition.VariableType.ToString());
+            }
+        };
     }
 
     public override void PostVisit(ProcedureCall procedureCall)

Canon.Core/SyntaxNodes/Expression.cs

@@ -48,6 +48,11 @@ public class Expression : NonTerminatedSyntaxNode
     /// </summary>
     public bool IsIfCondition { get; set; }
 
+    /// <summary>
+    /// 是否为WHILE语句中的条件语句
+    /// </summary>
+    public bool IsWhileCondition { get; set; }
+
     /// <summary>
     /// 直接赋值产生式的事件
     /// </summary>

Canon.Core/SyntaxNodes/Statement.cs

@@ -29,6 +29,17 @@ public class ForGeneratorEventArgs : EventArgs
     public required Expression End { get; init; }
 
     public required Statement Sentence { get; init; }
+
+    public required TerminatedSyntaxNode Do { get; init; }
+}
+
+public class WhileGeneratorEventArgs : EventArgs
+{
+    public required Expression Condition { get; init; }
+
+    public required Statement Sentence { get; init; }
+
+    public required TerminatedSyntaxNode Do { get; init; }
 }
 
 public class Statement : NonTerminatedSyntaxNode
@@ -62,6 +73,11 @@ public class Statement : NonTerminatedSyntaxNode
     /// </summary>
     public event EventHandler<ForGeneratorEventArgs>? OnForGenerator;
 
+    /// <summary>
+    /// 使用While产生式的事件
+    /// </summary>
+    public event EventHandler<WhileGeneratorEventArgs>? OnWhileGenerator;
+
     public static Statement Create(List<SyntaxNodeBase> children)
     {
         return new Statement { Children = children };
@@ -77,6 +93,16 @@ public class Statement : NonTerminatedSyntaxNode
                     Variable = Children[0].Convert<Variable>(), Expression = Children[2].Convert<Expression>()
                 });
         }
+        else if (Children.Count == 4)
+        {
+            OnWhileGenerator?.Invoke(this,
+                new WhileGeneratorEventArgs
+                {
+                    Condition = Children[1].Convert<Expression>(),
+                    Do = Children[2].Convert<TerminatedSyntaxNode>(),
+                    Sentence = Children[3].Convert<Statement>(),
+                });
+        }
         else if (Children.Count == 5)
         {
             OnIfGenerator?.Invoke(this,
@@ -95,6 +121,7 @@ public class Statement : NonTerminatedSyntaxNode
                     Iterator = Children[1].Convert<TerminatedSyntaxNode>().Token.Convert<IdentifierSemanticToken>(),
                     Begin = Children[3].Convert<Expression>(),
                     End = Children[5].Convert<Expression>(),
+                    Do = Children[6].Convert<TerminatedSyntaxNode>(),
                     Sentence = Children[7].Convert<Statement>()
                 });
         }

Canon.Core/SyntaxNodes/TerminatedSyntaxNode.cs

@@ -7,6 +7,16 @@ public class TerminatedSyntaxNode : SyntaxNodeBase
 {
     public override bool IsTerminated => true;
 
+    /// <summary>
+    /// 是否为For循环定义中的DO节点
+    /// </summary>
+    public bool IsForNode { get; set; }
+
+    /// <summary>
+    /// 是否为While循环定义中的DO节点
+    /// </summary>
+    public bool IsWhileNode { get; set; }
+
     public override void PreVisit(SyntaxNodeVisitor visitor)
     {
         visitor.PreVisit(this);

Canon.Tests/GrammarParserTests/PascalGrammarTests.cs

@@ -243,4 +243,19 @@ public class PascalGrammarTests
 
         CompilerHelpers.Analyse(program);
     }
+
+    [Fact]
+    public void WhileLoopTest()
+    {
+        const string program = """
+                               program main;
+                               var i : integer;
+                               begin
+                               while i < 10 do
+                               i := i + 1;
+                               end.
+                               """;
+
+        CompilerHelpers.Analyse(program);
+    }
 }

Canon.Tests/LexicalParserTests/KeywordTypeTests.cs

@@ -28,6 +28,7 @@ public class KeywordTypeTests
     [InlineData("DO", KeywordType.Do)]
     [InlineData("true", KeywordType.True)]
     [InlineData("false", KeywordType.False)]
+    [InlineData("while",KeywordType.While)]
     public void SmokeTest(string input, KeywordType type)
     {
         IEnumerable<SemanticToken> tokensEnumerable = _lexer.Tokenize(new StringSourceReader(input));