From 4aab5c5feeb87d52cc4bc2aa9753c6140cb725ae Mon Sep 17 00:00:00 2001
From: hneemann <helmut.neemann@arcor.de>
Date: Mon, 12 Apr 2021 16:25:04 +0200
Subject: [PATCH] more cleanup of test case parser, see #708

---
 .../testing/parser/OperatorPrecedence.java    | 20 ++++++++-
 .../digital/testing/parser/Parser.java        | 44 +++++--------------
 2 files changed, 31 insertions(+), 33 deletions(-)

diff --git a/src/main/java/de/neemann/digital/testing/parser/OperatorPrecedence.java b/src/main/java/de/neemann/digital/testing/parser/OperatorPrecedence.java
index faed779b7..d6ac9039f 100644
--- a/src/main/java/de/neemann/digital/testing/parser/OperatorPrecedence.java
+++ b/src/main/java/de/neemann/digital/testing/parser/OperatorPrecedence.java
@@ -12,5 +12,23 @@ public enum OperatorPrecedence {
     /**
      * the operator precedences
      */
-    MUL, ADD, SHIFT, COMPARE, EQUAL, AND, XOR, OR
+    MUL, ADD, SHIFT, COMPARE, EQUAL, AND, XOR, OR;
+
+    /**
+     * @return the OperatorPrecedence to start with
+     */
+    public static OperatorPrecedence first() {
+        return OR;
+    }
+
+    /**
+     * @return the predecessor or null if there is none
+     */
+    public OperatorPrecedence getPredecessor() {
+        if (ordinal() == 0)
+            return null;
+        else
+            return values()[ordinal() - 1];
+    }
+
 }
diff --git a/src/main/java/de/neemann/digital/testing/parser/Parser.java b/src/main/java/de/neemann/digital/testing/parser/Parser.java
index 1431ffeb1..0511206f8 100644
--- a/src/main/java/de/neemann/digital/testing/parser/Parser.java
+++ b/src/main/java/de/neemann/digital/testing/parser/Parser.java
@@ -343,6 +343,18 @@ public class Parser {
         return value;
     }
 
+    private Expression parseExpression() throws IOException, ParserException {
+        return parseExpression(OperatorPrecedence.first());
+    }
+
+    private Expression parseExpression(OperatorPrecedence op) throws IOException, ParserException {
+        OperatorPrecedence pr = op.getPredecessor();
+        if (pr == null)
+            return parseExpression(op, this::parseIdent);
+        else
+            return parseExpression(op, () -> parseExpression(pr));
+    }
+
     private Expression parseExpression(OperatorPrecedence oppr, Next next) throws IOException, ParserException {
         Expression ac = next.next();
         while (tok.peek().getPrecedence() == oppr) {
@@ -354,38 +366,6 @@ public class Parser {
         return ac;
     }
 
-    private Expression parseExpression() throws IOException, ParserException {
-        return parseExpression(OperatorPrecedence.OR, this::parseXOR);
-    }
-
-    private Expression parseXOR() throws IOException, ParserException {
-        return parseExpression(OperatorPrecedence.XOR, this::parseAND);
-    }
-
-    private Expression parseAND() throws IOException, ParserException {
-        return parseExpression(OperatorPrecedence.AND, this::parseEquals);
-    }
-
-    private Expression parseEquals() throws IOException, ParserException {
-        return parseExpression(OperatorPrecedence.EQUAL, this::parseCompare);
-    }
-
-    private Expression parseCompare() throws IOException, ParserException {
-        return parseExpression(OperatorPrecedence.COMPARE, this::parseShift);
-    }
-
-    private Expression parseShift() throws IOException, ParserException {
-        return parseExpression(OperatorPrecedence.SHIFT, this::parseAdd);
-    }
-
-    private Expression parseAdd() throws IOException, ParserException {
-        return parseExpression(OperatorPrecedence.ADD, this::parseMul);
-    }
-
-    private Expression parseMul() throws IOException, ParserException {
-        return parseExpression(OperatorPrecedence.MUL, this::parseIdent);
-    }
-
     private Expression parseIdent() throws IOException, ParserException {
         Tokenizer.Token t = tok.next();
         switch (t) {