def {}
// and
script {} 
// and
parallel objects

def projectName(projectPrefix, flavor) {
    return "${projectPrefix} ${flavor}"
}
def templateProjectNode (project, flavor, publish) {
    return {
        node {
            stage(projectName(project, flavor)) {
                try {
                    sh "hostname"
                    script {
                        sh label: "Compile + Test + Publish", script: "hostname"
                    }
                }
                finally {
                    junit "*/target/test-reports/**/*.xml"
                    archiveArtifacts "*/target/test-reports/**"
                    archiveArtifacts "*/target/*/*report/**"
                }
            }
        }
     }
}
def generateProjects (projectList) {
    def projects = projectList.collectEntries {
        [(projectName(it[0], it[1])): templateProjectNode(it[0], it[1], it[2])]
    }
    parallel projects
}

pipeline {
    stages {
        stage("a") {
            steps {
                sh "hostname"
            }
        }
        stage("b") {
            steps {
                sh "hostname"
            }
        }
        stage("c") {
            steps {
                sh "hostname"
            }
        }
        stage("Compile + Test + Publish") {
            parallel {
                stage("Frontend") {
                    steps {
                        sh "hostname"
                    }
                }
                stage("Magic") {
                    steps {
                        script {
                            projectList = [
                                ["D", "QQ", true],
                                ["D", "RR", true],
                                ["E", "QQ", true],
                                ["F", "QQ", true],
                                ["F", "RR", true],
                                ["G", "QQ", true],
                                ["H", "QQ", false],
                            ]
                            generateProjects(projectList)
                        }
                    }
                }
            }
        }
        stage("j") {
            steps {
                sh "hostname"
            }
        }
        stage("k") {
            steps {
                sh "hostname"
            }
        }
        stage("l") {
            when {
                branch "master"
            }
            steps {
                sh "hostname"
            }
        }
    }
}