:toc: macro :toclevels: 5 :figure-caption!:
Pragmater
¶ ↑
A command line interface that does one thing well by being entirely focused on managing/formatting source file en.wikipedia.org/wiki/Directive_(programming)[directive pragmas] (a.k.a. _magic comments_). Examples:
- source,ruby
! /usr/bin/env ruby # frozen_string_literal: true # encoding: UTF-8
With www.ruby-lang.org/en/news/2015/12/25/ruby-2-3-0-released[Ruby 2.3.0], frozen strings are supported via a pragma. This gem provides an easy way to insert or remove pragmas to single or multiple Ruby source files in order to benefit from improved memory and concurrency performance.
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Features¶ ↑
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Supports inserting a pragma or multiple pragmas to single or multiple source files.
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Supports removing pragma(s) from single or multiple source files.
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Supports file list filtering. Defaults to any file.
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Ensures duplicate pragmas never exist.
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Ensures pragmas are consistently formatted.
Requirements¶ ↑
Setup¶ ↑
To install with security, run:
- source,bash
# 💡 Skip this line if you already have the public certificate installed. gem cert –add <(curl –compressed –location alchemists.io/gems.pem) gem install pragmater –trust-policy HighSecurity
To install without security, run:
- source,bash
gem install pragmater
Usage¶ ↑
Command Line Interface (CLI)¶ ↑
From the command line, type: ‘pragmater –help`
image:https://alchemists.io/images/projects/pragmater/screenshots/usage.png
Both the ‘insert` and `remove` commands support the same options for specifying pragmas and/or included files. Example:
- source,bash
pragmater insert –comments “# frozen_string_literal: true” –patterns “Gemfile” “Guardfile” “Rakefile” “.gemspec” “config.ru” “bin/*/” “*/.rake” “*/.rb”
The ‘insert` and `remove` commands default to the current working directory so a path isn’t necessary unless you want to run
Pragmater
in a directory structure other than your current working directory.Customization¶ ↑
This gem can be configured via a global configuration: ‘$HOME/.config/pragmater/configuration.yml`
It can also be configured via https://alchemists.io/projects/xdg[XDG] environment variables.
The default configuration is as follows:
- source,yaml
comments: [] patterns: [] root_dir: “.”
Feel free to take the above configuration, modify, and save as your own custom ‘configuration.yml`.
The ‘configuration.yml` file can be configured as follows:
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‘comments`: Defines the array of pragmas you want to insert into your source files. Whatever is defined here will be the default used for insert and remove operations.
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‘includes`: Defines the array file patterns to apply to. Whatever is defined here will be the default used for insert and remove operations.
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‘root_dir`: Defines the root directory to apply the `includes` patterns too. By default, this will be the current directory you are running
Pragmater
from but can be a different directory entirely.
Available Pragmas¶ ↑
With Ruby 2.3 and higher, the following pragmas are available:
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‘# encoding:` Defaults to `UTF-8` but any supported encoding can be used. For a list of values, launch an IRB session and run `Encoding.name_list`.
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‘# coding:` The shorthand for `# encoding:`. Supports the same values as mentioned above.
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‘# frozen_string_literal:` Defaults to `false` but can take either `true` or `false` as a value. When enabled, Ruby will throw errors when strings are used in a mutable fashion.
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‘# warn_indent:` Defaults to `false` but can take either `true` or `false` as a value. When enabled, and running Ruby with the `-w` option, it’ll throw warnings for code that isn’t indented by two spaces.
Syntax¶ ↑
The pragma syntax allows for two kinds of styles. Example:
- source,ruby
# encoding: UTF-8 # -*- encoding: UTF-8 -*-
Only the former syntax is supported by this gem as the latter syntax is more verbose and requires additional typing.
Precedence¶ ↑
When different multiple pragmas are defined, they all take precedence:
- source,ruby
# encoding: binary # frozen_string_literal: true
In the above example, both binary encoding and _frozen string literals_ behavior will be applied.
When defining multiple pragmas that are similar, behavior can differ based on the kind of pragma used. The following walks through each use case so you know what to expect:
- source,ruby
# encoding: binary # encoding: UTF-8
In the above example, only the binary encoding will be applied while the UTF-8 encoding will be ignored (same principle applies for the ‘coding` pragma too).
- source,ruby
# frozen_string_literal: false # frozen_string_literal: true
In the above example, frozen string literal support _will be enabled_ instead of being disabled.
- source,ruby
# warn_indent: false # warn_indent: true
In the above example, indentation warnings _will be enabled_ instead of being disabled.
Frozen String Literals¶ ↑
Support for frozen string literals was added in Ruby 2.3.0. The ability to freeze strings within a source can be done by placing a frozen string pragma at the top of each source file. Example:
- source,ruby
# frozen_string_literal: true
This is great for selective enablement of frozen string literals but might be too much work for some (even with the aid of this gem). As an alternative, frozen string literals can be enabled via the following Ruby command line option:
.… –enable=frozen-string-literal .…
It is important to note that, once enabled, this freezes strings program-wide – It’s an all or nothing option.
Regardless of whether you leverage the capabilities of this gem or the Ruby command line option mentioned above, the following Ruby command line option is available to aid debugging and tracking down frozen string literal issues:
.… –debug=frozen-string-literal .…
Finally, you can use ‘–debug` (or `$DEBUG=true`) to force all raised exceptions to print to the console whether they are rescued or not. This is best used in conjunction with the above.
Ruby 2.3.0 also added the following methods to the ‘String` class:
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‘String#+@`: Answers a duplicated, mutable, string if not already frozen. Example:
+
- source,ruby
immutable = “test”.freeze mutable = +immutable
mutable.frozen? # false mutable.capitalize! # “Test”
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‘String#-@`: Answers a immutable string if not already frozen. Example:
+
- source,ruby
mutable = “test” immutable = -mutable
immutable.frozen? # true immutable.capitalize! # FrozenError
You can also use the methods, shown above, for variable initialization. Example:
- source,ruby
immutable = -“test” mutable = +“test”
immutable.frozen? # true mutable.frozen? # false
💡 Use of ‘+String#-@+` was https://bugs.ruby-lang.org/issues/13077[enhanced in Ruby 2.5.0] to deduplicate all instances of the same string thus reducing your memory footprint. This can be valuable in situations where you are not using the frozen string comment and need to selectively freeze strings.
💡 Use of ‘+String#dup+` was https://github.com/ruby/ruby/pull/8952[significantly enhanced in Ruby 3.3.0] to be as performant as `pass:` so you can use `+String#dup+` instead of `pass:` since `+String#dup+` is easier to read.
Consistency¶ ↑
As an added bonus, this gem ensures pragmas for all analyzed files are formatted in a consistent style. This means there is always a space after the octothorp (‘#`). Here are multiple pragmas presented together for a visual comparison:
- source,ruby
! /usr/bin/env ruby # encoding: UTF-8 # coding: UTF-8 # frozen_string_literal: true # warn_indent: true
One oddity to the above is the use of ‘# !/usr/bin/env ruby` is not allowed but `#! /usr/bin/env ruby` is which is why spacing is slightly different for shell pragmas.
Development¶ ↑
To contribute, run:
- source,bash
git clone github.com/bkuhlmann/pragmater cd pragmater bin/setup
You can also use the IRB console for direct access to all objects:
- source,bash
bin/console
Tests¶ ↑
To test, run:
- source,bash
bin/rake
https://alchemists.io/policies/license[License]¶ ↑
https://alchemists.io/policies/security[Security]¶ ↑
https://alchemists.io/policies/code_of_conduct[Code of Conduct]¶ ↑
https://alchemists.io/policies/contributions[Contributions]¶ ↑
https://alchemists.io/policies/developer_certificate_of_origin[Developer Certificate of Origin]¶ ↑
https://alchemists.io/projects/pragmater/versions[Versions]¶ ↑
https://alchemists.io/community[Community]¶ ↑
Credits¶ ↑
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Built with https://alchemists.io/projects/gemsmith[Gemsmith].
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Engineered by https://alchemists.io/team/brooke_kuhlmann[Brooke Kuhlmann].
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