This represents a location in the source.
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.
TruffleRuby >= 24 defines REUSE_AS_BINARY_ON_TRUFFLERUBY
in defaults/truffleruby. However, TruffleRuby < 24 defines REUSE_AS_BINARY_ON_TRUFFLERUBY
directly in its copy of lib/rubygems/platform.rb, so it is not defined if RubyGems is updated (gem update –system). Instead, we define it here in that case, similar to bundler/lib/bundler/rubygems_ext.rb. We must define it here and not in platform.rb because platform.rb is loaded before defaults/truffleruby.
Available list of platforms for targeting Gem installations.
See ‘gem help platform` for information on platform matching.
BasicSpecification
is an abstract class which implements some common code used by both Specification and StubSpecification.
Installs a gem along with all its dependencies from local and remote gems.
Raised when removing a gem with the uninstall command fails
Used to raise parsing and loading errors
Potentially raised when a specification is validated.
Raised when a gem dependencies file specifies a ruby version that does not match the current version.