Archetype: add support for conditional blocks

archetype/engine-v2-json/src/main/java/io/helidon/build/archetype/v2/json/ScriptSerializer.java

@@ -35,6 +35,7 @@
 import io.helidon.build.archetype.engine.v2.Walker;
 import io.helidon.build.archetype.engine.v2.ast.Block;
 import io.helidon.build.archetype.engine.v2.ast.Condition;
+import io.helidon.build.archetype.engine.v2.ast.ConditionBlock;
 import io.helidon.build.archetype.engine.v2.ast.DeclaredBlock;
 import io.helidon.build.archetype.engine.v2.ast.Expression;
 import io.helidon.build.archetype.engine.v2.ast.Expression.Token;
@@ -195,8 +196,12 @@ public VisitResult visitInvocation(Invocation invocation, Script script) {
 
     @Override
     public VisitResult visitCondition(Condition cond, Script script) {
-        exprId = exprIds.computeIfAbsent(cond.expression(), this::exprId);
-        return VisitResult.CONTINUE;
+        return evaluate(cond.expression());
+    }
+
+    @Override
+    public VisitResult visitConditionBlock(ConditionBlock condition, JsonObjectBuilder arg) {
+        return evaluate(condition.expression());
     }
 
     @Override
@@ -369,6 +374,11 @@ private String exprId(Expression expr) {
         return exprId;
     }
 
+    private VisitResult evaluate(Expression expression) {
+        exprId = exprIds.computeIfAbsent(expression, this::exprId);
+        return VisitResult.CONTINUE;
+    }
+
     private static final class TokenVisitor implements Token.Visitor<JsonObjectBuilder> {
 
         @Override

archetype/engine-v2/src/main/java/io/helidon/build/archetype/engine/v2/Controller.java

@@ -21,6 +21,8 @@
 
 import io.helidon.build.archetype.engine.v2.ast.Block;
 import io.helidon.build.archetype.engine.v2.ast.Condition;
+import io.helidon.build.archetype.engine.v2.ast.ConditionBlock;
+import io.helidon.build.archetype.engine.v2.ast.Expression;
 import io.helidon.build.archetype.engine.v2.ast.Model;
 import io.helidon.build.archetype.engine.v2.ast.Node.VisitResult;
 import io.helidon.build.archetype.engine.v2.ast.Output;
@@ -92,10 +94,12 @@ public VisitResult postVisitBlock(Block block, Context ctx) {
 
     @Override
     public VisitResult visitCondition(Condition condition, Context ctx) {
-        if (condition.expression().eval(ctx::getValue)) {
-            return VisitResult.CONTINUE;
-        }
-        return VisitResult.SKIP_SUBTREE;
+        return evaluate(condition.expression(), ctx);
+    }
+
+    @Override
+    public VisitResult visitConditionBlock(ConditionBlock condition, Context ctx) {
+        return evaluate(condition.expression(), ctx);
     }
 
     /**
@@ -212,4 +216,11 @@ public static void walk(InputResolver resolver,
             throw new IllegalStateException("Invalid scope after walking block");
         }
     }
+
+    private VisitResult evaluate(Expression expression, Context ctx) {
+        if (expression.eval(ctx::getValue)) {
+            return VisitResult.CONTINUE;
+        }
+        return VisitResult.SKIP_SUBTREE;
+    }
 }

archetype/engine-v2/src/main/java/io/helidon/build/archetype/engine/v2/ScriptLoader.java

@@ -30,6 +30,7 @@
 
 import io.helidon.build.archetype.engine.v2.ast.Block;
 import io.helidon.build.archetype.engine.v2.ast.Condition;
+import io.helidon.build.archetype.engine.v2.ast.ConditionBlock;
 import io.helidon.build.archetype.engine.v2.ast.DynamicValue;
 import io.helidon.build.archetype.engine.v2.ast.Input;
 import io.helidon.build.archetype.engine.v2.ast.Invocation;
@@ -178,6 +179,7 @@ private static final class ReaderImpl implements SimpleXMLParser.Reader {
         private String qName;
         private Map<String, Value> attrs;
         private LinkedList<Context> stack;
+        private LinkedList<String> expressions;
         private Context ctx;
         private Script.Builder scriptBuilder;
 
@@ -188,6 +190,7 @@ private static final class ReaderImpl implements SimpleXMLParser.Reader {
         Script read(InputStream is, Path path) throws IOException {
             this.path = Objects.requireNonNull(path, "path is null");
             stack = new LinkedList<>();
+            expressions = new LinkedList<>();
             parser = SimpleXMLParser.create(is, this);
             parser.parse();
             if (scriptBuilder == null) {
@@ -198,7 +201,7 @@ Script read(InputStream is, Path path) throws IOException {
 
         @Override
         public void startElement(String qName, Map<String, String> attrs) {
-            this.qName = qName;
+            this.qName = qName.replace("-", "");
             this.attrs = Maps.mapValue(attrs, DynamicValue::create);
             Location location = Location.of(path, parser.lineNumber(), parser.charNumber());
             info = BuilderInfo.of(loader, path, location);
@@ -241,6 +244,11 @@ public void endElement(String name) {
 
         void processElement() {
             switch (qName) {
+                case "if":
+                case "elseif":
+                case "else":
+                    processCondition();
+                    return;
                 case "directory":
                 case "help":
                     stack.push(new Context(ctx.state, new ValueBuilder(ctx.builder, qName)));
@@ -338,6 +346,32 @@ void processValidation() {
             }
         }
 
+        void processCondition() {
+            String expression;
+            ConditionBlock.Builder builder;
+            Block.Kind kind = blockKind();
+            switch (kind) {
+                case IF:
+                    expression = processXmlEscapes(attrs.get("expr").asString());
+                    builder = ConditionBlock.builder(info, kind).expression(expression);
+                    expressions.push(expression);
+                    break;
+                case ELSEIF:
+                    expression = String.format("!(%s) && %s", expressions.pop(), processXmlEscapes(attrs.get("expr").asString()));
+                    builder = ConditionBlock.builder(info, kind).expression(expression);
+                    expressions.push(expression);
+                    break;
+                case ELSE:
+                    expression = expressions.pop();
+                    builder = ConditionBlock.builder(info, kind).expression(String.format("!(%s)", expression));
+                    break;
+                default:
+                    throw new XMLReaderException(String.format(
+                            "Invalid input block: %s. { element=%s }", kind, qName));
+            }
+            addChild(ctx.state, builder);
+        }
+
         void processPreset() {
             Block.Builder builder;
             Block.Kind kind = blockKind();

archetype/engine-v2/src/main/java/io/helidon/build/archetype/engine/v2/ast/Block.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, 2022 Oracle and/or its affiliates.
+ * Copyright (c) 2021, 2023 Oracle and/or its affiliates.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -277,6 +277,28 @@ default VisitResult postVisitModel(Model model, A arg) {
             return postVisitAny(model, arg);
         }
 
+        /**
+         * Visit a condition block.
+         *
+         * @param condition condition block
+         * @param arg   visitor argument
+         * @return result
+         */
+        default VisitResult visitConditionBlock(ConditionBlock condition, A arg) {
+            return visitAny(condition, arg);
+        }
+
+        /**
+         * Visit a condition block after traversing the nested nodes.
+         *
+         * @param condition condition block
+         * @param arg   visitor argument
+         * @return result
+         */
+        default VisitResult postVisitConditionBlock(ConditionBlock condition, A arg) {
+            return postVisitAny(condition, arg);
+        }
+
         /**
          * Visit any block.
          *
@@ -504,6 +526,21 @@ public enum Kind {
          * Invoke.
          */
         INVOKE,
+
+        /**
+         * If.
+         */
+        IF,
+
+        /**
+         * Else.
+         */
+        ELSE,
+
+        /**
+         * Else-if.
+         */
+        ELSEIF
     }
 
     /**

archetype/engine-v2/src/main/java/io/helidon/build/archetype/engine/v2/ast/ConditionBlock.java

@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2023 Oracle and/or its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.helidon.build.archetype.engine.v2.ast;
+
+/**
+ * ConditionBlock.
+ */
+public final class ConditionBlock extends Block {
+    private final Expression expression;
+
+    private ConditionBlock(Builder builder) {
+        super(builder);
+        this.expression = builder.expression;
+    }
+
+    /**
+     * Create a new Builder instance.
+     *
+     * @param info builder info
+     * @param kind kind
+     * @return  builder instance
+     */
+    public static Builder builder(BuilderInfo info, Kind kind) {
+        return new Builder(info, kind);
+    }
+
+    /**
+     * Get the expression.
+     *
+     * @return expression
+     */
+    public Expression expression() {
+        return expression;
+    }
+
+    @Override
+    public <A> VisitResult accept(Block.Visitor<A> visitor, A arg) {
+        return visitor.visitConditionBlock(this, arg);
+    }
+
+    @Override
+    public <A> VisitResult acceptAfter(Visitor<A> visitor, A arg) {
+        return visitor.postVisitConditionBlock(this, arg);
+    }
+
+    /**
+     * ConditionBlock builder.
+     */
+    public static final class Builder extends Block.Builder {
+        private Expression expression;
+
+        private Builder(BuilderInfo info, Kind kind) {
+            super(info, kind);
+        }
+
+        /**
+         * Set the expression.
+         *
+         * @param expression expression
+         * @return this builder
+         */
+        public Builder expression(String expression) {
+            this.expression = Expression.create(expression);
+            return this;
+        }
+
+        @Override
+        protected ConditionBlock doBuild() {
+            return new ConditionBlock(this);
+        }
+    }
+}

archetype/engine-v2/src/main/java/io/helidon/build/archetype/engine/v2/util/ArchetypeValidator.java

@@ -29,6 +29,7 @@
 import io.helidon.build.archetype.engine.v2.Walker;
 import io.helidon.build.archetype.engine.v2.ast.Block;
 import io.helidon.build.archetype.engine.v2.ast.Condition;
+import io.helidon.build.archetype.engine.v2.ast.ConditionBlock;
 import io.helidon.build.archetype.engine.v2.ast.Expression;
 import io.helidon.build.archetype.engine.v2.ast.Input;
 import io.helidon.build.archetype.engine.v2.ast.Input.DeclaredInput;
@@ -149,10 +150,9 @@ private List<Block> refs(String path, Context ctx) {
         return null;
     }
 
-    @Override
-    public VisitResult visitCondition(Condition condition, Context ctx) {
+    private VisitResult evaluate(Node node, Expression expression, Context ctx) {
         try {
-            condition.expression().eval(variable -> {
+            expression.eval(variable -> {
                 List<Block> refs = refs(variable, ctx);
                 if (refs == null || refs.isEmpty()) {
                     return null;
@@ -174,20 +174,30 @@ public VisitResult visitCondition(Condition condition, Context ctx) {
             });
         } catch (Expression.UnresolvedVariableException ex) {
             errors.add(String.format("%s %s: '%s'",
-                    condition.location(),
+                    node.location(),
                     EXPR_UNRESOLVED_VARIABLE,
                     ex.variable()));
         } catch (IllegalStateException ex) {
             errors.add(String.format(
                     "%s %s: '%s'",
-                    condition.location(),
+                    node.location(),
                     EXPR_EVAL_ERROR,
                     ex.getMessage()));
         }
         // visit all branches
         return VisitResult.CONTINUE;
     }
 
+    @Override
+    public VisitResult visitCondition(Condition condition, Context ctx) {
+        return evaluate(condition, condition.expression(), ctx);
+    }
+
+    @Override
+    public VisitResult visitConditionBlock(ConditionBlock condition, Context ctx) {
+        return evaluate(condition, condition.expression(), ctx);
+    }
+
     @Override
     public VisitResult visitPreset(Preset preset, Context ctx) {
         ctx.scope().putValue(preset.path(), preset.value(), preset.isModel(), ValueKind.LOCAL_VAR);