Represents the use of a case statement for pattern matching.
case true in false end ^^^^^^^^^
Represents a regular expression literal that contains interpolation that is being used in the predicate of a conditional to implicitly match against the last line read by an IO object.
if /foo #{bar} baz/ then end
^^^^^^^^^^^^^^^^
Represents a symbol literal that contains interpolation.
:"foo #{bar} baz"
^^^^^^^^^^^^^^^^^
Represents a regular expression literal used in the predicate of a conditional to implicitly match against the last line read by an IO object.
if /foo/i then end ^^^^^^
Represents writing local variables using a regular expression match with named capture groups.
/(?<foo>bar)/ =~ baz ^^^^^^^^^^^^^^^^^^^^
Represents a symbol literal or a symbol contained within a ‘%i` list.
:foo ^^^^ %i[foo] ^^^
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.
Generated when trying to lookup a gem to indicate that the gem was found, but that it isn’t usable on the current platform.
fetch and install read these and report them to the user to aid in figuring out why a gem couldn’t be installed.
An error that indicates we weren’t able to fetch some data from a source
Raised when a gem dependencies file specifies a ruby version that does not match the current version.
Raised to indicate that a system exit should occur with the specified exit_code
RemoteFetcher handles the details of fetching gems and gem information from a remote source.
SpecFetcher handles metadata updates from remote gem repositories.
Searches code for a syntax error
There are three main phases in the algorithm:
Sanitize/format input source
Search for invalid blocks
Format invalid blocks into something meaninful
This class handles the part.
The bulk of the heavy lifting is done in:
- CodeFrontier (Holds information for generating blocks and determining if we can stop searching) - ParseBlocksFromLine (Creates blocks into the frontier) - BlockExpand (Expands existing blocks to search more code)
## Syntax error detection
When the frontier holds the syntax error, we can stop searching
search = CodeSearch.new(<<~EOM) def dog def lol end EOM search.call search.invalid_blocks.map(&:to_s) # => # => ["def lol\n"]
Outputs code with highlighted lines
Whatever is passed to this class will be rendered even if it is “marked invisible” any filtering of output should be done before calling this class.
DisplayCodeWithLineNumbers.new(
lines: lines,
highlight_lines: [lines[2], lines[3]]
).call
# =>
1
2 def cat
> 3 Dir.chdir
> 4 end
5 end
6
Explains syntax errors based on their source
example:
source = "def foo; puts 'lol'" # Note missing end explain ExplainSyntax.new( code_lines: CodeLine.from_source(source) ).call explain.errors.first # => "Unmatched keyword, missing `end' ?"
When the error cannot be determined by lexical counting then the parser is run against the input and the raw errors are returned.
Example:
source = "1 * " # Note missing a second number explain ExplainSyntax.new( code_lines: CodeLine.from_source(source) ).call explain.errors.first # => "syntax error, unexpected end-of-input"
The default port for HTTPS URIs is 443, and the scheme is ‘https:’ rather than ‘http:’. Other than that, HTTPS URIs are identical to HTTP URIs; see URI::HTTP.
The default port for LDAPS URIs is 636, and the scheme is ‘ldaps:’ rather than ‘ldap:’. Other than that, LDAPS URIs are identical to LDAP URIs; see URI::LDAP.
This is not an existing class, but documentation of the interface that Scheduler object should comply to in order to be used as argument to Fiber.scheduler and handle non-blocking fibers. See also the “Non-blocking fibers” section in Fiber class docs for explanations of some concepts.
Scheduler’s behavior and usage are expected to be as follows:
When the execution in the non-blocking Fiber reaches some blocking operation (like sleep, wait for a process, or a non-ready I/O), it calls some of the scheduler’s hook methods, listed below.
Scheduler somehow registers what the current fiber is waiting on, and yields control to other fibers with Fiber.yield (so the fiber would be suspended while expecting its wait to end, and other fibers in the same thread can perform)
At the end of the current thread execution, the scheduler’s method scheduler_close is called
The scheduler runs into a wait loop, checking all the blocked fibers (which it has registered on hook calls) and resuming them when the awaited resource is ready (e.g. I/O ready or sleep time elapsed).
This way concurrent execution will be achieved transparently for every individual Fiber’s code.
Scheduler implementations are provided by gems, like Async.
Hook methods are:
io_wait, io_read, io_write, io_pread, io_pwrite, and io_select, io_close
(the list is expanded as Ruby developers make more methods having non-blocking calls)
When not specified otherwise, the hook implementations are mandatory: if they are not implemented, the methods trying to call hook will fail. To provide backward compatibility, in the future hooks will be optional (if they are not implemented, due to the scheduler being created for the older Ruby version, the code which needs this hook will not fail, and will just behave in a blocking fashion).
It is also strongly recommended that the scheduler implements the fiber method, which is delegated to by Fiber.schedule.
Sample toy implementation of the scheduler can be found in Ruby’s code, in test/fiber/scheduler.rb
AbstractSyntaxTree provides methods to parse Ruby code into abstract syntax trees. The nodes in the tree are instances of RubyVM::AbstractSyntaxTree::Node.
This module is MRI specific as it exposes implementation details of the MRI abstract syntax tree.
This module is experimental and its API is not stable, therefore it might change without notice. As examples, the order of children nodes is not guaranteed, the number of children nodes might change, there is no way to access children nodes by name, etc.
If you are looking for a stable API or an API working under multiple Ruby implementations, consider using the prism gem, which is the official Ruby API to parse Ruby code.