Evaluates a string containing Ruby source code, or the given block, within the context of the receiver (obj). In order to set the context, the variable self is set to obj while the code is executing, giving the code access to obj’s instance variables and private methods.
When instance_eval is given a block, obj is also passed in as the block’s only argument.
When instance_eval is given a String, the optional second and third parameters supply a filename and starting line number that are used when reporting compilation errors.
class KlassWithSecret def initialize @secret = 99 end private def the_secret "Ssssh! The secret is #{@secret}." end end k = KlassWithSecret.new k.instance_eval { @secret } #=> 99 k.instance_eval { the_secret } #=> "Ssssh! The secret is 99." k.instance_eval {|obj| obj == self } #=> true
Bind umeth to recv and then invokes the method with the specified arguments. This is semantically equivalent to umeth.bind(recv).call(args, ...).
In general, while a TracePoint callback is running, other registered callbacks are not called to avoid confusion by reentrance. This method allows the reentrance in a given block. This method should be used carefully, otherwise the callback can be easily called infinitely.
If this method is called when the reentrance is already allowed, it raises a RuntimeError.
Example:
# Without reentry # --------------- line_handler = TracePoint.new(:line) do |tp| next if tp.path != __FILE__ # only work in this file puts "Line handler" binding.eval("class C; end") end.enable class_handler = TracePoint.new(:class) do |tp| puts "Class handler" end.enable class B end # This script will print "Class handler" only once: when inside :line # handler, all other handlers are ignored # With reentry # ------------ line_handler = TracePoint.new(:line) do |tp| next if tp.path != __FILE__ # only work in this file next if (__LINE__..__LINE__+3).cover?(tp.lineno) # don't be invoked from itself puts "Line handler" TracePoint.allow_reentry { binding.eval("class C; end") } end.enable class_handler = TracePoint.new(:class) do |tp| puts "Class handler" end.enable class B end # This wil print "Class handler" twice: inside allow_reentry block in :line # handler, other handlers are enabled.
Note that the example shows the principal effect of the method, but its practical usage is for debugging libraries that sometimes require other libraries hooks to not be affected by debugger being inside trace point handling. Precautions should be taken against infinite recursion in this case (note that we needed to filter out calls by itself from :line handler, otherwise it will call itself infinitely).
Return the called name of the method being called
Returns the current execution stack—an array containing backtrace location objects.
See Thread::Backtrace::Location for more information.
The optional start parameter determines the number of initial stack entries to omit from the top of the stack.
A second optional length parameter can be used to limit how many entries are returned from the stack.
Returns nil if start is greater than the size of current execution stack.
Optionally you can pass a range, which will return an array containing the entries within the specified range.
Returns an array containing elements selected by the block.
With a block given, calls the block with successive elements; returns an array of those elements for which the block returns a truthy value:
(0..9).select {|element| element % 3 == 0 } # => [0, 3, 6, 9] a = {foo: 0, bar: 1, baz: 2}.select {|key, value| key.start_with?('b') } a # => {:bar=>1, :baz=>2}
With no block given, returns an Enumerator.
Related: reject.
Dump the contents of the ruby heap as JSON.
output argument is the same as for dump.
full must be a boolean. If true, all heap slots are dumped including the empty ones (T_NONE).
since must be a non-negative integer or nil.
If since is a positive integer, only objects of that generation and newer generations are dumped. The current generation can be accessed using GC::count. Objects that were allocated without object allocation tracing enabled are ignored. See ::trace_object_allocations for more information and examples.
If since is omitted or is nil, all objects are dumped.
shapes must be a boolean or a non-negative integer.
If shapes is a positive integer, only shapes newer than the provided shape id are dumped. The current shape_id can be accessed using RubyVM.stat(:next_shape_id).
If shapes is false, no shapes are dumped.
To only dump objects allocated past a certain point you can combine since and shapes:
ObjectSpace.trace_object_allocations GC.start gc_generation = GC.count shape_generation = RubyVM.stat(:next_shape_id) call_method_to_instrument ObjectSpace.dump_all(since: gc_generation, shapes: shape_generation)
This method is only expected to work with C Ruby. This is an experimental method and is subject to change. In particular, the function signature and output format are not guaranteed to be compatible in future versions of ruby.
Returns the source file origin from the given object.
See ::trace_object_allocations for more information and examples.
Returns the original line from source for from the given object.
See ::trace_object_allocations for more information and examples.
Returns garbage collector generation for the given object.
class B include ObjectSpace def foo trace_object_allocations do obj = Object.new p "Generation is #{allocation_generation(obj)}" end end end B.new.foo #=> "Generation is 3"
See ::trace_object_allocations for more information and examples.
Returns true if the named file is writable by the real user and group id of this process. See access(3).
Note that some OS-level security features may cause this to return true even though the file is not writable by the real user/group.
Returns true if the named file is executable by the real user and group id of this process. See access(3).
Windows does not support execute permissions separately from read permissions. On Windows, a file is only considered executable if it ends in .bat, .cmd, .com, or .exe.
Note that some OS-level security features may cause this to return true even though the file is not executable by the real user/group.
Return measured GC total time in nano seconds.
True if the requested gem has already been installed.
Installing a git gem only involves building the extensions and generating the executables.
This is a null install as this specification is already installed. options are ignored.
This is a null install as a locked specification is considered installed. options are ignored.
Installs this specification using the Gem::Installer options. The install method yields a Gem::Installer instance, which indicates the gem will be installed, or nil, which indicates the gem is already installed.
After installation spec is updated to point to the just-installed specification.
This is a null install as this gem was unpacked into a directory. options are ignored.
Calls the constructed Function, with args. Caller must ensure the underlying function is called in a thread-safe manner if running in a multi-threaded process.
Note that it is not thread-safe to use this method to directly or indirectly call many Ruby C-extension APIs unless you don’t pass +need_gvl: true+ to Fiddle::Function#new.
For an example see Fiddle::Function
Allocates a C struct with the types provided.
See Fiddle::Pointer.malloc for memory management issues.