Added an expression parser to use for #if. #169

src/main/java/dk/camelot64/kickc/parser/ExpressionParser.java

@@ -0,0 +1,35 @@
+package dk.camelot64.kickc.parser;
+
+import dk.camelot64.kickc.model.CompileError;
+import org.antlr.v4.runtime.*;
+
+
+/**
+ * Parser for C-expressions.
+ * <p>
+ * Used by #if in the preprocessor
+ */
+public class ExpressionParser {
+
+   /**
+    * Parse an expression
+    *
+    * @param tokenSource The tokens to parse
+    * @return The parsed expression
+    */
+   public static KickCParser.ExprContext parseExpression(TokenSource tokenSource) {
+      CParser cParser = new CParser(null);
+      KickCParser kickCParser = new KickCParser(new CommonTokenStream(tokenSource), cParser);
+      kickCParser.addErrorListener(new BaseErrorListener() {
+         @Override
+         public void syntaxError(Recognizer<?, ?> recognizer, Object offendingSymbol, int line, int charPositionInLine, String msg, RecognitionException e) {
+            //StatementSource subSource =
+            //      new StatementSource(source.getFileName(), source.getLineNumber() + line, source.getCode(), source.getStartIndex(), source.getStopIndex());
+            throw new CompileError("Error parsing expression " + msg);
+         }
+      });
+      kickCParser.setBuildParseTree(true);
+      return kickCParser.expr();
+   }
+
+}

src/test/java/dk/camelot64/kickc/parsing/TestExpressionParser.java

@@ -0,0 +1,73 @@
+package dk.camelot64.kickc.parsing;
+
+import dk.camelot64.kickc.parser.*;
+import junit.framework.TestCase;
+import org.antlr.v4.runtime.CharStreams;
+import org.antlr.v4.runtime.CodePointCharStream;
+import org.antlr.v4.runtime.tree.TerminalNode;
+import org.junit.Test;
+
+import java.io.IOException;
+import java.net.URISyntaxException;
+
+public class TestExpressionParser {
+
+   /**
+    * Test the ExpressionParser
+    */
+   @Test
+   public void testExpressionParser() {
+      assertExpression("1", "1");
+      assertExpression("1+1", "+(1,1)");
+      assertExpression("1+1*-2", "+(1,*(1,-(2)))");
+      assertExpression("(1+1)*2", "*([+(1,1)],2)");
+      assertExpression("FIELDS*2<MAX", "<(*(FIELDS,2),MAX)");
+   }
+
+   private void assertExpression(String expr, String expected) {
+      CodePointCharStream fragmentCharStream = CharStreams.fromString(expr);
+      CParser cParser = new CParser(null);
+      KickCLexer kickCLexer = new KickCLexer(fragmentCharStream, cParser);
+      KickCParser.ExprContext exprContext = ExpressionParser.parseExpression(kickCLexer);
+      final KickCParserBaseVisitor<String> exprVisitor = new ExprPrinter();
+      final String exprOut = exprVisitor.visit(exprContext);
+      TestCase.assertEquals("Expression output does not match ", expected, exprOut);
+   }
+
+
+   /** Prints the expression. */
+   private static class ExprPrinter extends KickCParserBaseVisitor<String> {
+
+      @Override
+      public String visitExprBinary(KickCParser.ExprBinaryContext ctx) {
+         final String left = this.visit(ctx.expr(0));
+         String op = ((TerminalNode) ctx.getChild(1)).getSymbol().getText();
+         final String right = this.visit(ctx.expr(1));
+         return op+"("+left+","+right+")";
+      }
+
+      @Override
+      public String visitExprUnary(KickCParser.ExprUnaryContext ctx) {
+         String op = ((TerminalNode) ctx.getChild(0)).getSymbol().getText();
+         final String right = this.visit(ctx.expr());
+         return op+"("+right+")";
+      }
+
+      @Override
+      public String visitExprPar(KickCParser.ExprParContext ctx) {
+         final String sub = this.visit(ctx.commaExpr());
+         return "["+sub+"]";
+      }
+
+      @Override
+      public String visitExprNumber(KickCParser.ExprNumberContext ctx) {
+         return ctx.NUMBER().getText();
+      }
+
+      @Override
+      public String visitExprId(KickCParser.ExprIdContext ctx) {
+         return ctx.NAME().getText();
+      }
+   }
+
+}

src/test/java/dk/camelot64/kickc/test/TestKickAssRun.java

@@ -14,6 +14,9 @@ import java.nio.file.Paths;
 
 public class TestKickAssRun {
 
+   /**
+    * Test running KickAsm assembler to compile an ASM file
+    */
    @Test
    public void testKickAssRun() throws IOException, URISyntaxException {
       ReferenceHelper asmHelper = new ReferenceHelperFolder("src/test/java/dk/camelot64/kickc/test/");