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 ripper is run against the input and the raw ripper errors 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 parser gem or Ripper. If you would like to make RubyVM::AbstractSyntaxTree stable, please join the discussion at bugs.ruby-lang.org/issues/14844.
The Process::Sys module contains UID and GID functions which provide direct bindings to the system calls of the same names instead of the more-portable versions of the same functionality found in the Process, Process::UID, and Process::GID modules.
Emit a scalar with value and tag
Emit a sequence with list and tag
Emit a sequence with map and tag
Emit an arbitrary object obj and tag
Called with encoding when the YAML stream starts. This method is called once per stream. A stream may contain multiple documents.
See the constants in Psych::Parser for the possible values of encoding.
Called when the document starts with the declared version, tag_directives, if the document is implicit.
version will be an array of integers indicating the YAML version being dealt with, tag_directives is a list of tuples indicating the prefix and suffix of each tag, and implicit is a boolean indicating whether the document is started implicitly.
Given the following YAML:
%YAML 1.1 %TAG ! tag:tenderlovemaking.com,2009: --- !squee
The parameters for start_document must be this:
version # => [1, 1] tag_directives # => [["!", "tag:tenderlovemaking.com,2009:"]] implicit # => false
Called with the document ends. implicit is a boolean value indicating whether or not the document has an implicit ending.
Given the following YAML:
--- hello world
implicit will be true. Given this YAML:
--- hello world ...
implicit will be false.
Called when a sequence is started.
anchor is the anchor associated with the sequence or nil. tag is the tag associated with the sequence or nil. implicit a boolean indicating whether or not the sequence was implicitly started. style is an integer indicating the list style.
See the constants in Psych::Nodes::Sequence for the possible values of style.
Here is a YAML document that exercises most of the possible ways this method can be called:
--- - !!seq [ a ] - &pewpew - b
The above YAML document consists of three lists, an outer list that contains two inner lists. Here is a matrix of the parameters sent to represent these lists:
# anchor tag implicit style [nil, nil, true, 1 ] [nil, "tag:yaml.org,2002:seq", false, 2 ] ["pewpew", nil, true, 1 ]
Called when a sequence ends.
Called when a map starts.
anchor is the anchor associated with the map or nil. tag is the tag associated with the map or nil. implicit is a boolean indicating whether or not the map was implicitly started. style is an integer indicating the mapping style.
See the constants in Psych::Nodes::Mapping for the possible values of style.
Here is a YAML document that exercises most of the possible ways this method can be called:
---
k: !!map { hello: world }
v: &pewpew
hello: world
The above YAML document consists of three maps, an outer map that contains two inner maps. Below is a matrix of the parameters sent in order to represent these three maps:
# anchor tag implicit style [nil, nil, true, 1 ] [nil, "tag:yaml.org,2002:map", false, 2 ] ["pewpew", nil, true, 1 ]
Called when a map ends
Called when the YAML stream ends