Improve RegexInterpreter

kmizu · Dec 19, 2016 · 67cf54b · 67cf54b
1 parent 44446e2
commit 67cf54b
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Showing 5 changed files with 70 additions and 3 deletions.
diff --git a/src/main/java/com/github/kmizu/jcombinator/showcase/regex/AstNode.java b/src/main/java/com/github/kmizu/jcombinator/showcase/regex/AstNode.java
@@ -5,6 +5,7 @@
 public class AstNode {
     public interface RVisitor<R, C> {
         public R visitRGrouped(RGrouped node, C context);
+        public R visitRAny(RAny node, C context);
         public R visitRString(RString node, C context);
         public R visitRChoice(RChoice node, C context);
         public R visitRSequence(RSequence node, C context);
@@ -30,6 +31,15 @@ public <R, C> R accept(RVisitor<R, C> visitor, C context) {
             return visitor.visitRString(this, context);
         }
     }
+    public static class RAny extends RExpression {
+        public RAny() {
+        }
+
+        @Override
+        public <R, C> R accept(RVisitor<R, C> visitor, C context) {
+            return visitor.visitRAny(this, context);
+        }
+    }
     public static class RChoice extends RExpression {
         private final RExpression lhs, rhs;
 

diff --git a/src/main/java/com/github/kmizu/jcombinator/showcase/regex/RegexInterpreter.java b/src/main/java/com/github/kmizu/jcombinator/showcase/regex/RegexInterpreter.java
@@ -17,6 +17,11 @@ public AstNode.RExpression visitRString(AstNode.RString node, Void context) {
             return node;
         }
 
+        @Override
+        public AstNode.RExpression visitRAny(AstNode.RAny node, Void context) {
+            return node;
+        }
+
         @Override
         public AstNode.RExpression visitRChoice(AstNode.RChoice node, Void context) {
             return new AstNode.RChoice(
@@ -74,6 +79,17 @@ public Boolean visitRString(AstNode.RString node, SuccessfullContinuation contex
             }
         }
 
+        @Override
+        public Boolean visitRAny(AstNode.RAny node, SuccessfullContinuation context) {
+            String slice = input.substring(cursor);
+            if(slice.length() > 0) {
+                cursor++;
+                return context.invoke();
+            } else {
+                return false;
+            }
+        }
+
         @Override
         public Boolean visitRChoice(AstNode.RChoice node, SuccessfullContinuation context) {
             final int start = cursor;

diff --git a/src/main/java/com/github/kmizu/jcombinator/showcase/regex/RegexParser.java b/src/main/java/com/github/kmizu/jcombinator/showcase/regex/RegexParser.java
@@ -44,7 +44,7 @@ public Rule<AstNode.RExpression> repeatable() {
 
     public Rule<AstNode.RExpression> primary() {
         return rule(() ->
-            grouped().or(single()).or(escaped())
+            grouped().or(single()).or(escaped()).or(rany())
         );
     }
 
@@ -64,9 +64,14 @@ public Rule<AstNode.RExpression> escaped() {
             string("\\").cat(meta()).map(t -> new AstNode.RString(t.item2()))
         );
     }
+    public Rule<AstNode.RExpression> rany() {
+        return rule(() ->
+            string(".").map(__ -> new AstNode.RAny())
+        );
+    }
     public Rule<String> meta() {
         return rule(() ->
-                set('|', '*', '+', '(', ')', '\\')
+            set('|', '*', '+', '(', ')', '.', '\\')
         );
     }
 }
diff --git a/src/test/java/com/github/kmizu/jcombinator/AllTests.java b/src/test/java/com/github/kmizu/jcombinator/AllTests.java
@@ -4,6 +4,6 @@
 import org.junit.runners.Suite;
 
 @RunWith(Suite.class)
-@Suite.SuiteClasses({PrimitiveTest.class, ChainlTest.class})
+@Suite.SuiteClasses({PrimitiveTest.class, ChainlTest.class, RegexTest.class})
 public class AllTests {
 }
diff --git a/src/test/java/com/github/kmizu/jcombinator/RegexTest.java b/src/test/java/com/github/kmizu/jcombinator/RegexTest.java
@@ -0,0 +1,36 @@
+package com.github.kmizu.jcombinator;
+
+import com.github.kmizu.jcombinator.showcase.regex.RegexInterpreter;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+import static org.junit.Assert.*;
+
+@RunWith(JUnit4.class)
+public class RegexTest {
+    private RegexInterpreter i;
+    @Before
+    public void initializeInterpreter() {
+        i = new RegexInterpreter();
+    }
+    @Test
+    public void testPrimitives() {
+        assertTrue(i.matches("a", "a"));
+        assertFalse(i.matches("b", "a"));
+        assertFalse(i.matches("a", "b"));
+        assertTrue(i.matches(".", "a"));
+        assertTrue(i.matches(".", "b"));
+    }
+
+    @Test
+    public void testSequence() {
+        assertTrue(i.matches("ab", "ab"));
+        assertTrue(i.matches("bc", "bc"));
+        assertTrue(i.matches(".a", "xa"));
+        assertTrue(i.matches(".a", "ya"));
+        assertTrue(i.matches(".a", "za"));
+        assertFalse(i.matches(".a", "xb"));
+    }
+}