From f4eda906e729c118cc577139c8a0f5fa1af43f88 Mon Sep 17 00:00:00 2001
From: Kraemerd <Dominic_Daniel.Kraemer@Student.Reutlingen-University.de>
Date: Mon, 9 Jan 2023 02:54:38 +0100
Subject: [PATCH] implemented ASTPrinter to test the visitor pattern
---
expressions.txt | 5 ++---
src/ASTPrinter.java | 38 ++++++++++++++++++++++++++++++++++++++
src/Application.java | 3 ++-
3 files changed, 42 insertions(+), 4 deletions(-)
create mode 100644 src/ASTPrinter.java
diff --git a/expressions.txt b/expressions.txt
index 363a033..55a3a7c 100644
--- a/expressions.txt
+++ b/expressions.txt
@@ -1,5 +1,4 @@
-1 + xy^2 - (31 * x)y
+1 + x*y^2 - (31 * x)-y
1 + x^2 - (3 * x)
-2x + 0.5x^2 - 1
-((5+2)-8)-8+12
+2-x + 0.5*x^2 - 1
(5*2-(5^2)+3*(201.01-15))
\ No newline at end of file
diff --git a/src/ASTPrinter.java b/src/ASTPrinter.java
new file mode 100644
index 0000000..a057d9a
--- /dev/null
+++ b/src/ASTPrinter.java
@@ -0,0 +1,38 @@
+public class ASTPrinter implements Visitor<String>{
+ @Override
+ public String visit(final Parser.BinaryOperation binaryOP) {
+ StringBuffer sb = new StringBuffer();
+ if(binaryOP.capsuled) {
+ sb.append("(");
+ }
+ sb.append(binaryOP.leftExpression.accept(this));
+ sb.append(binaryOP.operator);
+ sb.append(binaryOP.rightExpression.accept(this));
+ if(binaryOP.capsuled) {
+ sb.append(")");
+ }
+ return sb.toString();
+ }
+
+ @Override
+ public String visit(Parser.Variable variable) {
+ return variable.variableName;
+ }
+
+ @Override
+ public String visit(Parser.Number number) {
+ return number.digits;
+ }
+
+ @Override
+ public String visit(Parser.Decimal decimal) {
+ return decimal.beforeDot.digits + "." + decimal.afterDot.digits;
+ }
+
+ public String visit(final Parser.Expression ast) {
+ if(ast==null) {
+ throw new RuntimeException("AST is null");
+ }
+ return ast.accept(this);
+ }
+}
diff --git a/src/Application.java b/src/Application.java
index a4c744f..f185a6a 100644
--- a/src/Application.java
+++ b/src/Application.java
@@ -40,7 +40,8 @@ public class Application {
Parser parser = new Parser();
try {
Parser.Expression exp = parser.parse(tokens);
- System.out.println(exp.toString());
+ ASTPrinter printer = new ASTPrinter();
+ System.out.println("Printing: '" + printer.visit(exp) + "'");
}
catch (ParserException e) {
System.out.println(e.getMessage());
--
GitLab