Move compile-to-groovy visitors into nf-lang

modules/nextflow/src/main/groovy/nextflow/ast/NextflowDSLImpl.groovy

@@ -36,6 +36,8 @@ import nextflow.script.TokenStdoutCall
 import nextflow.script.TokenValCall
 import nextflow.script.TokenValRef
 import nextflow.script.TokenVar
+import nextflow.script.control.GStringToLazyVisitor
+import nextflow.script.control.TaskCmdXformVisitor
 import org.codehaus.groovy.ast.ASTNode
 import org.codehaus.groovy.ast.ClassCodeVisitorSupport
 import org.codehaus.groovy.ast.ClassNode

modules/nextflow/src/main/groovy/nextflow/ast/TaskCmdXform.groovy

@@ -23,6 +23,7 @@ import java.lang.annotation.Target
 
 import groovy.transform.CompileStatic
 import groovy.util.logging.Slf4j
+import nextflow.script.control.TaskCmdXformVisitor
 import org.codehaus.groovy.ast.ASTNode
 import org.codehaus.groovy.ast.ClassNode
 import org.codehaus.groovy.control.CompilePhase

modules/nextflow/src/main/groovy/nextflow/config/parser/v2/ConfigToGroovyXform.groovy

@@ -22,6 +22,7 @@ import java.lang.annotation.RetentionPolicy
 import java.lang.annotation.Target
 
 import groovy.transform.CompileStatic
+import nextflow.config.control.ConfigToGroovyVisitor
 import org.codehaus.groovy.ast.ASTNode
 import org.codehaus.groovy.control.CompilePhase
 import org.codehaus.groovy.control.SourceUnit

modules/nextflow/src/main/groovy/nextflow/script/parser/v2/ScriptCompiler.java

@@ -36,6 +36,7 @@
 import nextflow.script.control.ModuleResolver;
 import nextflow.script.control.ResolveIncludeVisitor;
 import nextflow.script.control.ScriptResolveVisitor;
+import nextflow.script.control.ScriptToGroovyVisitor;
 import nextflow.script.control.TypeCheckingVisitor;
 import nextflow.script.parser.ScriptParserPluginFactory;
 import org.codehaus.groovy.ast.ASTNode;

modules/nextflow/src/main/groovy/nextflow/config/parser/v2/ConfigToGroovyVisitor.java → modules/nf-lang/src/main/java/nextflow/config/control/ConfigToGroovyVisitor.java

@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package nextflow.config.parser.v2;
+package nextflow.config.control;
 
 import java.util.ArrayList;
 import java.util.stream.Collectors;
@@ -34,8 +34,9 @@
 import static org.codehaus.groovy.ast.tools.GeneralUtils.*;
 
 /**
- * Visitor to convert a Nextflow config AST into a
- * Groovy AST which is executed against {@link ConfigDsl}.
+ * Transform a Nextflow config AST into a Groovy AST.
+ *
+ * @see nextflow.config.parser.v2.ConfigDsl
  *
  * @author Ben Sherman <bentshermann@gmail.com>
  */

modules/nf-lang/src/main/java/nextflow/script/control/GStringToLazyVisitor.java

@@ -0,0 +1,99 @@
+/*
+ * Copyright 2013-2024, Seqera Labs
+ *
+ * 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 nextflow.script.control;
+
+import org.codehaus.groovy.ast.ClassCodeVisitorSupport;
+import org.codehaus.groovy.ast.expr.ClosureExpression;
+import org.codehaus.groovy.ast.expr.Expression;
+import org.codehaus.groovy.ast.expr.GStringExpression;
+import org.codehaus.groovy.control.SourceUnit;
+
+import static org.codehaus.groovy.ast.tools.GeneralUtils.*;
+
+/**
+ * Transform a GString to a Lazy GString.
+ *
+ * from
+ *   "${foo} ${bar}"
+ * to
+ *   "${->foo} ${->bar}
+ *
+ * @author Paolo Di Tommaso <paolo.ditommaso@gmail.com>
+ */
+public class GStringToLazyVisitor extends ClassCodeVisitorSupport {
+
+    private SourceUnit sourceUnit;
+
+    private boolean inClosure;
+
+    public GStringToLazyVisitor(SourceUnit sourceUnit) {
+        this.sourceUnit = sourceUnit;
+    }
+
+    @Override
+    protected SourceUnit getSourceUnit() {
+        return sourceUnit;
+    }
+
+    @Override
+    public void visitClosureExpression(ClosureExpression node) {
+        inClosure = true;
+        try {
+            super.visitClosureExpression(node);
+        }
+        finally {
+            inClosure = false;
+        }
+    }
+
+    @Override
+    public void visitGStringExpression(GStringExpression node) {
+        // gstrings in a closure will be lazily evaluated and therefore
+        // don't need to be lazy themselves
+        if( !inClosure ) {
+            transformToLazy(node);
+        }
+    }
+
+    private void transformToLazy(GStringExpression node) {
+        var values = node.getValues();
+        var lazyValues = new Expression[values.size()];
+
+        // wrap all non-closure expressions in a closure
+        for( int i = 0; i < values.size(); i++ ) {
+            var value = values.get(i);
+            if( value instanceof ClosureExpression ) {
+                // when the value is already a closure, skip the entire gstring
+                // because it is assumed to already be lazy
+                return;
+            }
+            lazyValues[i] = wrapExpressionInClosure(value);
+        }
+
+        for( int i = 0; i < values.size(); i++ ) {
+            values.set(i, lazyValues[i]);
+        }
+    }
+
+    protected ClosureExpression wrapExpressionInClosure(Expression node)  {
+        // note: the closure parameter argument must be *null* to force the creation of a closure like {-> something}
+        // otherwise it creates a closure with an implicit parameter that is managed in a different manner by the
+        // GString -- see http://docs.groovy-lang.org/latest/html/documentation/#_special_case_of_interpolating_closure_expressions
+        return closureX(null, block(stmt(node)));
+    }
+
+}

modules/nextflow/src/main/groovy/nextflow/script/parser/v2/ScriptToGroovyVisitor.java → modules/nf-lang/src/main/java/nextflow/script/control/ScriptToGroovyVisitor.java

@@ -13,14 +13,12 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package nextflow.script.parser.v2;
+package nextflow.script.control;
 
 import java.util.List;
 import java.util.Set;
 import java.util.stream.Collectors;
 
-import nextflow.ast.GStringToLazyVisitor;
-import nextflow.ast.TaskCmdXformVisitor;
 import nextflow.script.ast.ASTNodeMarker;
 import nextflow.script.ast.AssignmentExpression;
 import nextflow.script.ast.FeatureFlagNode;
@@ -58,8 +56,9 @@
 import static org.codehaus.groovy.ast.tools.GeneralUtils.*;
 
 /**
- * Visitor to convert a Nextflow script AST into a
- * Groovy AST which is executed against {@link BaseScript}.
+ * Transform a Nextflow script AST into a Groovy AST.
+ *
+ * @see nextflow.script.BaseScript
  *
  * @author Ben Sherman <bentshermann@gmail.com>
  */
@@ -349,7 +348,7 @@ private Expression varToStrX(Expression node) {
     }
 
     protected ClosureExpression wrapExpressionInClosure(Expression node)  {
-        return closureX(block(new VariableScope(), stmt(node)));
+        return closureX(block(stmt(node)));
     }
 
     private Statement processWhen(Expression when) {