[incubator-kie-drools#5708] [new-parser] function definition causes a… (

apache#5793)

* [incubator-kie-drools#5708] [new-parser] function definition causes an error

* - enhance getTextPreservingWhitespace to avoid string manipulation

drools-drl/drools-drl-parser-tests/src/test/java/org/drools/drl/parser/antlr4/MiscDRLParserTest.java

@@ -3691,4 +3691,52 @@ void groupedConstraintsWithNullSafeDereferencing() {
                 .as("prefix should be appended to each element")
                 .isEqualToIgnoringWhitespace("address!.city!.startsWith(\"I\") && address!.city!.length() == 5");
     }
+
+    @Test
+    public void functionWithStringLiteral() {
+        final String text = "function String star(String s) { return \"*\"; }";
+        PackageDescr packageDescr = parser.parse(text);
+        assertThat(parser.hasErrors()).as(parser.getErrors().toString()).isFalse();
+
+        FunctionDescr function = packageDescr.getFunctions().get( 0 );
+
+        assertThat(function.getName()).isEqualTo("star");
+        assertThat(function.getReturnType()).isEqualTo("String");
+        assertThat(function.getParameterTypes().get(0)).isEqualTo("String");
+        assertThat(function.getParameterNames().get(0)).isEqualTo("s");
+        assertThat(function.getBody()).isEqualToIgnoringWhitespace( "return \"*\";");
+    }
+
+    @Test
+    public void functionWithStringLiteralAddition() {
+        final String text = "function String addStar(String s) { return s + \"*\"; }";
+        PackageDescr packageDescr = parser.parse(text);
+        assertThat(parser.hasErrors()).as(parser.getErrors().toString()).isFalse();
+
+        FunctionDescr function = packageDescr.getFunctions().get( 0 );
+
+        assertThat(function.getName()).isEqualTo("addStar");
+        assertThat(function.getReturnType()).isEqualTo("String");
+        assertThat(function.getParameterTypes().get(0)).isEqualTo("String");
+        assertThat(function.getParameterNames().get(0)).isEqualTo("s");
+        assertThat(function.getBody()).isEqualToIgnoringWhitespace( "return s + \"*\";");
+    }
+
+    @Test
+    public void functionWithMultipleBlockStatements() {
+        final String text = "function String star(String s) {\n" +
+                "    String result = s + \"*\";\n" +
+                "    return result;\n" +
+                "}";
+        PackageDescr packageDescr = parser.parse(text);
+        assertThat(parser.hasErrors()).as(parser.getErrors().toString()).isFalse();
+
+        FunctionDescr function = packageDescr.getFunctions().get( 0 );
+
+        assertThat(function.getName()).isEqualTo("star");
+        assertThat(function.getReturnType()).isEqualTo("String");
+        assertThat(function.getParameterTypes().get(0)).isEqualTo("String");
+        assertThat(function.getParameterNames().get(0)).isEqualTo("s");
+        assertThat(function.getBody()).isEqualToIgnoringWhitespace( "String result = s + \"*\"; return result;");
+    }
 }

drools-drl/drools-drl-parser/src/main/antlr4/org/drools/drl/parser/antlr4/DRLParser.g4

@@ -164,7 +164,7 @@ drlRelationalOperator
     | DRL_NOT? DRL_STR LBRACK IDENTIFIER RBRACK ;
 
 /* function := FUNCTION type? ID parameters(typed) chunk_{_} */
-functiondef : DRL_FUNCTION typeTypeOrVoid? IDENTIFIER formalParameters block ;
+functiondef : DRL_FUNCTION typeTypeOrVoid? IDENTIFIER formalParameters drlBlock ;
 
 
 /* extending JavaParser qualifiedName */
@@ -380,7 +380,7 @@ fromAccumulate : (DRL_ACCUMULATE|DRL_ACC) LPAREN lhsAndDef (COMMA|SEMI)
                  RPAREN (SEMI)?
                  ;
 
-blockStatements : blockStatement* ;
+blockStatements : drlBlockStatement* ;
 
 /*
 accumulateFunction := label? ID parameters
@@ -512,3 +512,57 @@ drlVariableInitializer
  drlArrayInitializer
      : LBRACE (drlVariableInitializer (COMMA drlVariableInitializer)* (COMMA)? )? RBRACE
      ;
+
+/* extending JavaParser block */
+drlBlock
+    : LBRACE drlBlockStatement* RBRACE
+    ;
+/* extending JavaParser blockStatement */
+drlBlockStatement
+    : drlLocalVariableDeclaration SEMI
+    | drlStatement
+    | localTypeDeclaration
+    ;
+
+/* extending JavaParser statement */
+drlStatement
+    : blockLabel=drlBlock
+    | ASSERT drlExpression (COLON drlExpression)? SEMI
+    | IF parExpression drlStatement (ELSE drlStatement)?
+    | FOR LPAREN forControl RPAREN drlStatement
+    | WHILE parExpression drlStatement
+    | DO drlStatement WHILE parExpression SEMI
+    | TRY drlBlock (catchClause+ finallyBlock? | finallyBlock)
+    | TRY resourceSpecification drlBlock catchClause* finallyBlock?
+    | SWITCH parExpression LBRACE switchBlockStatementGroup* switchLabel* RBRACE
+    | SYNCHRONIZED parExpression drlBlock
+    | RETURN drlExpression? SEMI
+    | THROW drlExpression SEMI
+    | BREAK drlIdentifier? SEMI
+    | CONTINUE drlIdentifier? SEMI
+    | YIELD drlExpression SEMI // Java17
+    | SEMI
+    | statementExpression=drlExpression SEMI
+    | switchExpression SEMI? // Java17
+    | identifierLabel=drlIdentifier COLON drlStatement
+    ;
+
+/* extending JavaParser localVariableDeclaration */
+drlLocalVariableDeclaration
+    : variableModifier* (typeType drlVariableDeclarators | VAR drlIdentifier ASSIGN expression)
+    ;
+
+/* extending JavaParser variableDeclarators */
+drlVariableDeclarators
+    : drlVariableDeclarator (COMMA drlVariableDeclarator)*
+    ;
+
+/* extending JavaParser variableDeclarator */
+drlVariableDeclarator
+    : drlVariableDeclaratorId (ASSIGN drlVariableInitializer)?
+    ;
+
+/* extending JavaParser variableDeclaratorId */
+drlVariableDeclaratorId
+    : drlIdentifier (LBRACK RBRACK)*
+    ;

drools-drl/drools-drl-parser/src/main/java/org/drools/drl/parser/antlr4/Antlr4ParserStringUtils.java

@@ -18,6 +18,9 @@
  */
 package org.drools.drl.parser.antlr4;
 
+import java.util.List;
+import java.util.stream.Collectors;
+
 import org.antlr.v4.runtime.ParserRuleContext;
 import org.antlr.v4.runtime.TokenStream;
 import org.antlr.v4.runtime.misc.Interval;
@@ -59,6 +62,13 @@ public static String getTextPreservingWhitespace(ParserRuleContext ctx) {
         return ctx.start.getTokenSource().getInputStream().getText(interval);
     }
 
+    /**
+     * Get text from List of ParserRuleContext's CharStream without trimming whitespace
+     */
+    public static String getTextPreservingWhitespace(List<? extends ParserRuleContext> ctx) {
+        return ctx.stream().map(Antlr4ParserStringUtils::getTextPreservingWhitespace).collect(Collectors.joining());
+    }
+
     /**
      * Get text from ParserRuleContext's CharStream without trimming whitespace
      * tokenStream is required to get hidden channel token (e.g. whitespace).
@@ -78,4 +88,5 @@ public static String trimThen(String rhs) {
             throw new DRLParserException("rhs has to start with 'then' : rhs = " + rhs);
         }
     }
+
 }

drools-drl/drools-drl-parser/src/main/java/org/drools/drl/parser/antlr4/DRLVisitorImpl.java

@@ -59,11 +59,11 @@
 import org.drools.drl.ast.descr.UnitDescr;
 import org.drools.drl.ast.descr.WindowDeclarationDescr;
 
-import static org.drools.drl.parser.antlr4.DRLParserHelper.getTextWithoutErrorNode;
 import static org.drools.drl.parser.antlr4.Antlr4ParserStringUtils.getTextPreservingWhitespace;
 import static org.drools.drl.parser.antlr4.Antlr4ParserStringUtils.getTokenTextPreservingWhitespace;
 import static org.drools.drl.parser.antlr4.Antlr4ParserStringUtils.safeStripStringDelimiters;
 import static org.drools.drl.parser.antlr4.Antlr4ParserStringUtils.trimThen;
+import static org.drools.drl.parser.antlr4.DRLParserHelper.getTextWithoutErrorNode;
 import static org.drools.drl.parser.util.ParserStringUtils.appendPrefix;
 import static org.drools.util.StringUtils.unescapeJava;
 
@@ -193,7 +193,7 @@ public FunctionDescr visitFunctiondef(DRLParser.FunctiondefContext ctx) {
                 functionDescr.addParameter(typeTypeContext.getText(), variableDeclaratorIdContext.getText());
             });
         }
-        functionDescr.setBody(getTextPreservingWhitespace(ctx.block()));
+        functionDescr.setBody(getTextPreservingWhitespace(ctx.drlBlock().drlBlockStatement()));
         return functionDescr;
     }