Represents the use of the ‘&&=` operator on a call to the `[]` method.
foo.bar[baz] &&= value ^^^^^^^^^^^^^^^^^^^^^^
Represents the use of an assignment operator on a call to ‘[]`.
foo.bar[baz] += value ^^^^^^^^^^^^^^^^^^^^^
Represents the use of the ‘||=` operator on a call to `[]`.
foo.bar[baz] ||= value ^^^^^^^^^^^^^^^^^^^^^^
Represents assigning to an index.
foo[bar], = 1 ^^^^^^^^ begin rescue => foo[bar] ^^^^^^^^ end for foo[bar] in baz do end ^^^^^^^^
Represents reading a local variable. Note that this requires that a local variable of the same name has already been written to in the same scope, otherwise it is parsed as a method call.
foo ^^^
Represents writing local variables using a regular expression match with named capture groups.
/(?<foo>bar)/ =~ baz ^^^^^^^^^^^^^^^^^^^^
Represents the use of the ‘^` operator for pinning a variable in a pattern matching expression.
foo in ^bar ^^^^
Represents a singleton class declaration involving the ‘class` keyword.
class << self end ^^^^^^^^^^^^^^^^^
A cache that can be used to quickly compute code unit offsets from byte offsets. It purposefully provides only a single []
method to access the cache in order to minimize surface area.
Note that there are some known issues here that may or may not be addressed in the future:
The first is that there are issues when the cache computes values that are not on character boundaries. This can result in subsequent computations being off by one or more code units.
The second is that this cache is currently unbounded. In theory we could introduce some kind of LRU cache to limit the number of entries, but this has not yet been implemented.
A pattern is an object that wraps a Ruby pattern matching expression. The expression would normally be passed to an ‘in` clause within a `case` expression or a rightward assignment expression. For example, in the following snippet:
case node in ConstantPathNode[ConstantReadNode[name: :Prism], ConstantReadNode[name: :Pattern]] end
the pattern is the ConstantPathNode[...]
expression.
The pattern gets compiled into an object that responds to call by running the compile
method. This method itself will run back through Prism
to parse the expression into a tree, then walk the tree to generate the necessary callable objects. For example, if you wanted to compile the expression above into a callable, you would:
callable = Prism::Pattern.new("ConstantPathNode[ConstantReadNode[name: :Prism], ConstantReadNode[name: :Pattern]]").compile callable.call(node)
The callable object returned by compile
is guaranteed to respond to call with a single argument, which is the node to match against. It also is guaranteed to respond to ===
, which means it itself can be used in a ‘case` expression, as in:
case node when callable end
If the query given to the initializer cannot be compiled into a valid matcher (either because of a syntax error or because it is using syntax we do not yet support) then a Prism::Pattern::CompilationError
will be raised.
A class that knows how to walk down the tree. None of the individual visit methods are implemented on this visitor, so it forces the consumer to implement each one that they need. For a default implementation that continues walking the tree, see the Visitor
class.
A visitor is a class that provides a default implementation for every accept method defined on the nodes. This means it can walk a tree without the caller needing to define any special handling. This allows you to handle a subset of the tree, while still walking the whole tree.
For example, to find all of the method calls that call the ‘foo` method, you could write:
class FooCalls < Prism::Visitor def visit_call_node(node) if node.name == "foo" # Do something with the node end # Call super so that the visitor continues walking the tree super end end
Gem::ConfigFile
RubyGems options and gem command options from gemrc.
gemrc is a YAML
file that uses strings to match gem command arguments and symbols to match RubyGems options.
Gem
command arguments use a String
key that matches the command name and allow you to specify default arguments:
install: --no-rdoc --no-ri update: --no-rdoc --no-ri
You can use gem:
to set default arguments for all commands.
RubyGems options use symbol keys. Valid options are:
:backtrace
See backtrace
:sources
Sets Gem::sources
:verbose
See verbose
:concurrent_downloads
gemrc files may exist in various locations and are read and merged in the following order:
system wide (/etc/gemrc)
per user (~/.gemrc)
per environment (gemrc files listed in the GEMRC environment variable)
Raised when there are conflicting gem specs loaded
Example using a Gem::Package
Builds a .gem file given a Gem::Specification
. A .gem file is a tarball which contains a data.tar.gz, metadata.gz, checksums.yaml.gz and possibly signatures.
require 'rubygems' require 'rubygems/package' spec = Gem::Specification.new do |s| s.summary = "Ruby based make-like utility." s.name = 'rake' s.version = PKG_VERSION s.requirements << 'none' s.files = PKG_FILES s.description = <<-EOF Rake is a Make-like program implemented in Ruby. Tasks and dependencies are specified in standard Ruby syntax. EOF end Gem::Package.build spec
Reads a .gem file.
require 'rubygems' require 'rubygems/package' the_gem = Gem::Package.new(path_to_dot_gem) the_gem.contents # get the files in the gem the_gem.extract_files destination_directory # extract the gem into a directory the_gem.spec # get the spec out of the gem the_gem.verify # check the gem is OK (contains valid gem specification, contains a not corrupt contents archive)
files
are the files in the .gem tar file, not the Ruby files in the gem extract_files
and contents
automatically call verify
Create a package based upon a Gem::Specification
. Gem
packages, as well as zip files and tar/gzipped packages can be produced by this task.
In addition to the Rake targets generated by Rake::PackageTask, a Gem::PackageTask
will also generate the following tasks:
Create a RubyGems package with the given name and version.
Example using a Gem::Specification
:
require 'rubygems' require 'rubygems/package_task' spec = Gem::Specification.new do |s| s.summary = "Ruby based make-like utility." s.name = 'rake' s.version = PKG_VERSION s.requirements << 'none' s.files = PKG_FILES s.description = <<-EOF Rake is a Make-like program implemented in Ruby. Tasks and dependencies are specified in standard Ruby syntax. EOF end Gem::PackageTask.new(spec) do |pkg| pkg.need_zip = true pkg.need_tar = true end
Subclass of StreamUI that instantiates the user interaction using $stdin, $stdout, and $stderr.
This class is useful for exploring contents before and after a block
It searches above and below the passed in block to match for whatever criteria you give it:
Example:
def dog # 1 puts "bark" # 2 puts "bark" # 3 end # 4 scan = AroundBlockScan.new( code_lines: code_lines block: CodeBlock.new(lines: code_lines[1]) ) scan.scan_while { true } puts scan.before_index # => 0 puts scan.after_index # => 3
This class is responsible for taking a code block that exists at a far indentaion and then iteratively increasing the block so that it captures everything within the same indentation block.
def dog puts "bow" puts "wow" end
block = BlockExpand.new
(code_lines: code_lines)
.call(CodeBlock.new(lines: code_lines[1]))
puts block.to_s # => puts “bow”
puts "wow"
Once a code block has captured everything at a given indentation level then it will expand to capture surrounding indentation.
block = BlockExpand.new
(code_lines: code_lines)
.call(block)
block.to_s # => def dog
puts "bow" puts "wow" end