LoopStatementParser使用抽象方法

src/main/java/org/jcnc/snow/compiler/parser/statement/LoopStatementParser.java

@@ -11,6 +11,7 @@ import org.jcnc.snow.compiler.parser.context.TokenStream;
 import org.jcnc.snow.compiler.parser.expression.PrattExpressionParser;
 import org.jcnc.snow.compiler.parser.factory.StatementParserFactory;
 import org.jcnc.snow.compiler.parser.util.FlexibleSectionParser;
+import org.jcnc.snow.compiler.parser.util.ParserUtils;
 
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -40,10 +41,9 @@ public class LoopStatementParser implements StatementParser {
         TokenStream ts = ctx.getTokens();
 
         // 匹配 loop:
-        ts.expect("loop");
+        ParserUtils.matchHeader(ts, "loop");
-        ts.expect(":");
+
-        ts.expectType(TokenType.NEWLINE);
+        ParserUtils.skipNewlines(ts);
-        skipNewlines(ts);
 
         // 用于保存各区块内容
         final StatementNode[] initializer = new StatementNode[1];
@@ -61,9 +61,9 @@ public class LoopStatementParser implements StatementParser {
                     ts1.expect("initializer");
                     ts1.expect(":");
                     ts1.expectType(TokenType.NEWLINE);
-                    skipNewlines(ts1);
+                    ParserUtils.skipNewlines(ts);
                     initializer[0] = StatementParserFactory.get(ts1.peek().getLexeme()).parse(ctx1);
-                    skipNewlines(ts1);
+                    ParserUtils.skipNewlines(ts);
                 }
         ));
 
@@ -74,10 +74,10 @@ public class LoopStatementParser implements StatementParser {
                     ts1.expect("condition");
                     ts1.expect(":");
                     ts1.expectType(TokenType.NEWLINE);
-                    skipNewlines(ts1);
+                    ParserUtils.skipNewlines(ts);
                     condition[0] = new PrattExpressionParser().parse(ctx1);
                     ts1.expectType(TokenType.NEWLINE);
-                    skipNewlines(ts1);
+                    ParserUtils.skipNewlines(ts);
                 }
         ));
 
@@ -88,14 +88,14 @@ public class LoopStatementParser implements StatementParser {
                     ts1.expect("update");
                     ts1.expect(":");
                     ts1.expectType(TokenType.NEWLINE);
-                    skipNewlines(ts1);
+                    ParserUtils.skipNewlines(ts);
 
                     String varName = ts1.expectType(TokenType.IDENTIFIER).getLexeme();
                     ts1.expect("=");
                     ExpressionNode updateExpr = new PrattExpressionParser().parse(ctx1);
                     ts1.expectType(TokenType.NEWLINE);
                     update[0] = new AssignmentNode(varName, updateExpr);
-                    skipNewlines(ts1);
+                    ParserUtils.skipNewlines(ts);
                 }
         ));
 
@@ -106,7 +106,7 @@ public class LoopStatementParser implements StatementParser {
                     ts1.expect("body");
                     ts1.expect(":");
                     ts1.expectType(TokenType.NEWLINE);
-                    skipNewlines(ts1);
+                    ParserUtils.skipNewlines(ts);
 
                     while (!(ts1.peek().getLexeme().equals("end") &&
                             ts1.peek(1).getLexeme().equals("body"))) {
@@ -114,13 +114,13 @@ public class LoopStatementParser implements StatementParser {
                                 ? ts1.peek().getLexeme()
                                 : "";
                         body.add(StatementParserFactory.get(keyword).parse(ctx1));
-                        skipNewlines(ts1);
+                        ParserUtils.skipNewlines(ts);
                     }
 
                     ts1.expect("end");
                     ts1.expect("body");
                     ts1.expectType(TokenType.NEWLINE);
-                    skipNewlines(ts1);
+                    ParserUtils.skipNewlines(ts);
                 }
         ));
 
@@ -128,16 +128,10 @@ public class LoopStatementParser implements StatementParser {
         FlexibleSectionParser.parse(ctx, ts, sections);
 
         // 匹配 loop 结束
-        ts.expect("end");
+        ParserUtils.matchFooter(ts, "loop");
-        ts.expect("loop");
+
-        ts.expectType(TokenType.NEWLINE);
 
         return new LoopNode(initializer[0], condition[0], update[0], body);
     }
-
+    
-    private void skipNewlines(TokenStream ts) {
-        while (ts.peek().getType() == TokenType.NEWLINE) {
-            ts.next();
-        }
-    }
 }

src/main/java/org/jcnc/snow/compiler/parser/util/ParserUtils.java

@@ -0,0 +1,46 @@
+package org.jcnc.snow.compiler.parser.util;
+
+import org.jcnc.snow.compiler.lexer.token.TokenType;
+import org.jcnc.snow.compiler.parser.context.TokenStream;
+
+/**
+ * 常用的语法解析工具类。
+ */
+public class ParserUtils {
+
+    /**
+     * 匹配开头部分，如 `loop:`、`function:`
+     *
+     * @param ts      Token 流
+     * @param keyword 关键词
+     */
+    public static void matchHeader(TokenStream ts, String keyword) {
+        ts.expect(keyword);
+        ts.expect(":");
+        ts.expectType(TokenType.NEWLINE);
+        skipNewlines(ts);
+    }
+
+    /**
+     * 匹配结尾部分，如 `end loop`、`end function`
+     *
+     * @param ts      Token 流
+     * @param keyword 关键词
+     */
+    public static void matchFooter(TokenStream ts, String keyword) {
+        ts.expect("end");
+        ts.expect(keyword);
+        ts.expectType(TokenType.NEWLINE);
+    }
+
+    /**
+     * 跳过多余换行
+     *
+     * @param ts Token 流
+     */
+    public static void skipNewlines(TokenStream ts) {
+        while (ts.peek().getType() == TokenType.NEWLINE) {
+            ts.next();
+        }
+    }
+}