dartrix 0.2.0

An Extensible Template Engine for Dart. Comes with a set of builtin templates, and supports extension by "plugin" template libraries.

Dartrix ToolSuite (beta)

An extensible templates and tools. Dartrix comes with a set of builtin templates to generate scripts, apps, libraries, etc. in multiple languages. It also supports third-party template libraries as "plugins". Several sample plugins are available; see below for details.

WARNING: This is a beta version. It is not compatible with previous alpha versions. If you wrote templates using previous versions you'll need to make some minor changes as described below. Windows users: it probably won't work, but it's on my TODO list. Linux users: it ought to work, but has only been tested on a Mac. Bug reports welcome.

NEW: This version adds support for automatic installation of plugins from pub.dev, meta-templates, generic templates, predefined scopes and libraries :here, :user, :local, and :dartrix, and a --Y parameter that tells Dartrix to copy a template verbatim.

Table of Contents

• Getting Started
• Dartrix Template Libraries
  • Available Libraries
  • Plugin Installation
• Dartrix commands
• Plugins
  • Third-Party
  • Local
• Developing Templates and Template Libraries

Getting Started

$ pub global activate dartrix
$ pub global run dartrix:list
## use 'dts'-prefixed aliases
$ dtslist
$ dtslist :d  # = :dartrix library
$ dtsnew :d bashrc --help
$ dtsnew --dry-run :d bashrc
$ dtsnew :d bashrc

Aliases for pub global run dartix:foo are dtsfoo, e.g. dtslist, dtsnew.

To use a different alias, create a file with bash aliases and source it from ~/.bashrc:

$ dtsnew :d bashrc --help
$ dtsnew :d bashrc --prefix t

This will create ./bashrc containing lines of the following form:

alias tlist="pub global run --enable-asserts dartrix:list $@"

Dartrix Template Libraries

Predefined:

• :. (:here) - any current working directory containing ./.dartrix.d/templates counts as a "here" library. Passing ':.' to a command will cause it to look only in the current working directory, e.g. dtsnew :. foo will instantiate the foo template in the current working directory (that is, ./.dartrix/templates/foo). This allow you to override installed templates, for example.
• :u (:user) - defaults to ~/.dartrix.d/templates
• :l (:local) - defaults to /usr/local/share/dartrix/templates
• :d (:dartrix) - Dartrix built-in templates

All other library tags will resolve to plugin libraries. Tag :foo will resolve to library (Dart package) foo_dartrix.

Available Libraries

At time of writing there are three libraries available on pub.dev:

• hello_dartrix is a library of templates that generate Hello World code for a variety of programming languages.

• dart_dartrix is a library of templates that generate Dart code.

• flutter_dartrix is a library of teplates the generate Flutter code.

At the moment these libraries only contain a few simple templates; more will be added in coming weeks. If you develop a template that you think belongs in one of them, plus submit a ticket to the appropriate Github repo.

Plugin Installation

Plugin libraries may be registered in three places. Libraries downloaded and installed from pub.dev are ordinary dart packages; they get installed in the syscache (~/.pub-cache). Users can also install plugins for private use or for sharing on a local multi-user system. You might want to do this during template development, or if your templates contain proprietary information.

Template libraries (plugins) published on pub.dev are automatically installed on first use. Use the dtslist command with the -p (--pubdev) parameter to see a list of available plugins (example below). This will list them but not install them. If you list the contents of a plugin it will be downloaded and installed (to ~/.pub-cache) automatically. Same thing if you use dtsnew on it.

User-scoped libraries are registered in ~/.dartrix.d/user.yaml, as shown below. Use of this is optional.

libraries:
  - name: foo_dartrix
    path: path/to/foo_dartrix
  - name: bar_dartrix
    path: path/to/bar_dartrix

Local-scoped libraries are registered similarly in /usr/local/share/dartrix/local.yaml. Use of this is optional.

The location of these libraries will be configurable in a future version.

NOTE the distinction between the :user library and libraries in "user scope". The latter are the libraries registered in ~/.dartrix.d/user.yaml, plus :user (~/.dartrix.d/templates). The same distinction holds between the :local library and libraries in "local scope".

In general you will only need to use user scoped libraries, and the :here library, when you are developing templates.

Local libraries are intended for sharing templates on multi-user systems. The list command by default ignores local scope; to enable it pass the -l (--local) flag.

Resolving template references

If one of the predefined library tags is used, Dartrix will look in that library only. For plugins Dartrix will search the local Dart syscache (~/.pub-cache) for a matching package.

Dartrix Commands

• list - print lists of template libraries and templates
• man - print manpages
• new - generate files from parameterized templates

For template development:

WARNING: these commands are still under development.

• lint - verifies that all the standard bits are in place, paths are legal, etc.
• update - generate missing docstring files, manpages, and template handlers.

List

The list command lists available template libraries and templates.

Sample output for $ pub global run dartrix:list --pubdev:

$ tlist --pubdev --local
dartrix:list, version 0.1.0

  Library       Version       Description
  :dartrix      0.2.0         builtin templates
  :here         [not used]    Here templates (./.dartrix.d/templates)
  :user                       User templates (~/.dartrix.d/templates)
  :local                      Local templates (/usr/local/share/dartrix/templates)
  --------
 +:dart         0.2.2         A Dartrix template library of Dart code.
                              path: /Users/gar/mobileink/dart_dartrix
 >:dart         0.2.2         Dartrix template plugin package.  Contains templates for Dart apps, libraries, packages, etc.
 ^:dart         0.2.2         Dartrix template plugin package.  Contains templates for Dart apps, libraries, packages, etc.
 *:flutter      0.2.0         A Dartrix template library of Flutter code.
                              path: /Users/gar/mobileink/flutter_dartrix
 +:flutter      0.2.0         A Dartrix template library of Flutter code.
                              path: /Users/gar/mobileink/flutter_dartrix
 >:flutter      0.1.0         Dartrix template plugin package.  Contains templates for Flutter code - apps, packages, plugins, widgets, etc.
 ^:flutter      0.1.0-beta    Dartrix template plugin package.  Contains templates for Flutter code - apps, packages, plugins, widgets, etc.
 *:hello        0.2.0         A Dartrix template library of Hello World demos.
                              path: /Users/gar/mobileink/hello_dartrix
 +:hello        0.2.0         A Dartrix template library of Hello World demos.
                              path: /Users/gar/mobileink/hello_dartrix
 ^:hello        0.1.0         Dartrix template plugin package.  Contains templates for "Hello World" in various programming languages.

*User  +Local  >Sys  ^pub.dev

In this example, package hello is listed three times:

• Version 0.1.0 was published to pub.dev
• Version 0.2.0 is registered in Local scope
• Version 0.2.0 is also registered in User scope.

In this case, the same code, in $HOME/dartrixdev/hello_dartrix, is registered as a plugin in both User and Local scopes. This is just for demo purposes, normally you probably would not do that.

new

The dtsnew command instantiates a template.

the --here parameter

This parameter tells Dartrix to write the output to ./.dartrix.d/templates. It only applies for meta-templates, and when --Y is used. This makes the results available in the :here library, which is useful if you want to begin developing a template but not a template library. Use a meta-template to generate a template in :here, and then edit it and use dtxnew :. mytemplate to use it.

Use --here in conjunction with --Y to modify any template.

the --Y parameter

The --Y parameter tells the dtsnew command to copy the template verbatim. It's named after the Y combinator, since you can think of it as finding a fixed point.

This allows you to easily copy and modify any template.

Plugins - Template Libraries

Developing Templates and Template Libraries

Detailed instructions for template development are (well, will be) provided in the manpages. The basic rules are:

• The package, the root directory of the package, and the main dart file must be named by the package name suffixed by "_dartrix". The root directory must contain a dartrix.yaml file that describes the library. Each template is represented by a subdirectory under the templates/ subdir, and must contain a .yaml file. For example, a library foobar containing two templates, foo and bar, should look like this:

foobar_dartrix/
    lib/foobar_dartrix.dart
    pubspec.yaml   # with "name: foobar_dartrix
    templates/
        foo/
          .yaml
          filea.mustache
        bar/
          .yaml
          fileb.mustache

• The file lib/foobar_dartrix.dart may be omitted if you do not plan to publish your library to pub.dev. It's only there because pub.dev wants to see it.
• Templates in the library are represented by subdirectories of templates/
• Template files are written in the {{mustache}} syntax, have a .mustache extension, and are stored in templates/, under the appropriate
• A library should contain manpages, stored in man/. A manpage should be provided for the library itself and for each template it contains, with corresponding names suffixed by .1. Manpages should provide detailed documentation.

Example of a dartrix.yaml file:

name        : mylib
version     : 0.2.2
docstring   : Short description of lib
description : More detailed description of lib
dartrix     : 0.2.0

An example of a template .yaml file:

name         : cmd_shell
version      : 0.2.1
docstring    : Dart command shell app
description  : A template for a command shell application.
dartrix      : 0.2.0   # version used to develop this template
params:
  sys:  # these are predefined parameters
    - id : package
      defaultsTo : myshell
    - id: out
      defaultsTo : <<package>>
  user:
    - name       : 'homepage'
      abbr       : 'w'
      docstring  : 'cmd prefix'
      defaultsTo : 'https://example.org/myapp'
      typeHint   : 'URL'
      help       : 'Homepage for app.'

Use the --Y parameter to copy any template and inspect its .yaml files.

hidden and private parameters

Hidden parameters are available for use but not described in the help screen; they are marked by property hidden: true. Private parameters are not exposed to the user at all; they provide a mechanism by which the template author can initialize template data without programming. They are indicated by property private: true.

path rewriting

Dartrix supports path rewriting. For a simple example see the java template in the hello_dartrix plugin. The general idea is that path segments in upper case will be rewritten.

To indicate that a parameter should be used in path rewriting, use the 'seg' property, e.g. 'seg: FOO' will cause path segments named FOO in the template source to be rewritten to the value of the parameter so annotated.

Uppercase segments with leading underscores are reserved.

predefined parameters

A small number of parameters are predefined to fit the most common use cases:

• ns - a namespace, in segmented.string format. The value of this parameter sets the following data fields, which become available in the template and for path rewriting:

  • {{dartrix.ns}}

  • _NS - the ns with '.' replaced by '/', for use in path rewriting

• nsx - namespace extension. This allows you to break a namespace into parts. For examle, org.acme.foo.bar could be treated as a namespace, or it could be broken into an ns part (org.acme) and an nsx part (foo.bar). Generates:

  • {{dartrix.nsx}}

  • _NSX - nsx with '.' replaced by '/', for path rewriting

• out - output path relative to current working directory. This makes it easy to give the user the option of controlling the output path. Generates:

  • {{dartrix.out}}

  • _OUT

tricks

Sometimes you want to print something, e.g. punctuation, only if a key has a value. For example, a namespace extension must be preceded by a dot; if the extension is null, the dot should be omitted.

A little mustache trickery takes care of this. Surround the output with a mustache "section", which will act as a conditional. For example:

{{#dartrix.nsx}}.{{dartrix.nsx}}{{/dartrix.nsx}}

This will print nothing unless dartrix.nsx has a value other than false, in which case it will print the '.' followed by the dartrix.nsx value. Dartrix will set the value to false if you do not set a default value or if you set it to the empty string '' (using defaultsTo).

See the java template of library hello_dartrix for an example.