1 files changed, 63 insertions, 0 deletions
diff --git a/src/java_cup/simple_calc/scanner.java b/src/java_cup/simple_calc/scanner.java
new file mode 100644
index 0000000..f8f850a
--- /dev/null
+++ b/src/java_cup/simple_calc/scanner.java
@@ -0,0 +1,63 @@
+// Simple Example Scanner Class
+
+package java_cup.simple_calc;
+
+import java_cup.runtime.Symbol;
+
+public class scanner implements java_cup.runtime.Scanner {
+  final java.io.InputStream instream;
+
+  public scanner(java.io.InputStream is) throws java.io.IOException {
+    instream = is;
+  }
+  public scanner() throws java.io.IOException { this(System.in); }
+
+  /* single lookahead character */
+  protected int next_char = -2;
+
+  /* advance input by one character */
+  protected void advance()
+    throws java.io.IOException
+    { next_char = instream.read(); }
+
+  /* initialize the scanner */
+  private void init()
+    throws java.io.IOException
+    { advance(); }
+
+  /* recognize and return the next complete token */
+  public Symbol next_token()
+    throws java.io.IOException
+    {
+      if (next_char==-2) init(); // set stuff up first time we are called.
+      for (;;)
+        switch (next_char)
+	  {
+	    case '0': case '1': case '2': case '3': case '4': 
+	    case '5': case '6': case '7': case '8': case '9': 
+	      /* parse a decimal integer */
+	      int i_val = 0;
+	      do {
+	        i_val = i_val * 10 + (next_char - '0');
+	        advance();
+	      } while (next_char >= '0' && next_char <= '9');
+	    return new Symbol(sym.NUMBER, new Integer(i_val));
+
+	    case ';': advance(); return new Symbol(sym.SEMI);
+	    case '+': advance(); return new Symbol(sym.PLUS);
+	    case '-': advance(); return new Symbol(sym.MINUS);
+	    case '*': advance(); return new Symbol(sym.TIMES);
+	    case '/': advance(); return new Symbol(sym.DIVIDE);
+	    case '%': advance(); return new Symbol(sym.MOD);
+	    case '(': advance(); return new Symbol(sym.LPAREN);
+	    case ')': advance(); return new Symbol(sym.RPAREN);
+
+	    case -1: return new Symbol(sym.EOF);
+
+	    default: 
+	      /* in this simple scanner we just ignore everything else */
+	      advance();
+	    break;
+	  }
+    }
+};