This is just an intial merge. It does not yet make generators and finally
work together.
Conflicts:
Zend/zend_language_scanner.c
Zend/zend_language_scanner_defs.h
Zend/zend_vm_def.h
Zend/zend_vm_execute.h
Zend/zend_vm_execute.skl
Zend/zend_vm_opcodes.h
foreach only allowed variables to be traversed by reference. This never
really made sense because
a) Expressions like array(&$a, &$b) can be meaningfully iterated by-ref
b) Function calls can return by-ref (so they can also be meaningfully
iterated)
c) Iterators could at least in theory also be iterated by-ref (not
sure if any iterator makes use of this)
With by-ref generators the restriction makes even less sense, so I removed
it altogether.
If yield is used in an expression context parenthesis are now required.
This ensures that the code is unambiguos.
Yield statements can still be used without parenthesis (which should be
the most common case).
Also yield expressions without value can be used without parenthesis,
too (this should be the most common case for coroutines).
If the yield expression is used in a context where parenthesis are required
anyway, no additional parenthesis have to be inserted.
Examples:
// Statements don't need parenthesis
yield $foo;
yield $foo => $bar;
// Yield without value doesn't need parenthesis either
$data = yield;
// Parentheses don't have to be duplicated
foo(yield $bar);
if (yield $bar) { ... }
// But we have to use parentheses here
$foo = (yield $bar);
This commit also fixes an issue with by-ref passing of $foo[0] like
variables. They previously weren't properly fetched for write.
Additionally this fixes valgrind warnings which were caused by access to
uninitialized memory in zend_is_function_or_method_call().
Generators are now automatically detected by the presence of a `yield`
expression in their body.
This removes the ZEND_SUSPEND_AND_RETURN_GENERATOR opcode. Instead
additional checks for ZEND_ACC_GENERATOR are added to the fcall_common
helper and zend_call_function.
This also adds a new function zend_generator_create_zval, which handles
the actual creation of the generator zval from an op array.
I feel like I should deglobalize the zend_create_execute_data_from_op_array
code a bit. It currently changes EG(current_execute_data) and
EG(opline_ptr) which is somewhat confusing (given the name).
Keys are yielded using the
yield $key => $value
syntax. Currently this is implemented as a statement only and not as an
expression, because conflicts arise considering nesting and use in arrays:
yield yield $a => $b;
// could be either
yield (yield $a) => $b;
// or
yield (yield $a => $b);
Once I find some way to resolve these conflicts this should be available
as an expression too.
Also the key yielding code is rather copy-and-past-y for the value yielding
code, so that should be factored out.
If the generator is used as a coroutine it often doesn't make sense to yield
anything. In this case one can simply receive values using
$value = yield;
The yield here will simply yield NULL.
Yield now is an expression and the return value is the value passed to
$generator->send(). By default (i.e. if ->next() is called) the value is
NULL.
Unlike in Python ->send() can be run without priming the generator with a
->next() call first.
Generator functions have to specify the * (asterix) modifier after the
function keyword. If they do so the ZEND_ACC_GENERATOR flag is added to
the fn_flags.
This change is as per RFC https://wiki.php.net/rfc/empty_isset_exprs.
The change allows passing the result of function calls and other
expressions to the empty() language construct. This is accomplished by
simply rewriting empty(expr) to !expr.
The change does not affect the suppression of errors when using empty()
on variables. empty($undefinedVar) will continue not to throw errors.
When an expression is used inside empty() on the other hand, errors will
not be suppressed. Thus empty($undefinedVar + $somethingElse) *will*
throw a notice.
The change also does not make empty() into a real function, so using
'empty' as a callback is still not possible.
In addition to the empty() changes the commit adds nicer error messages
when isset() is used on function call results or other expressions.
This fixes bug #60097.
Before two global variables CG(heredoc) and CG(heredoc_len) were used to
track the current heredoc label. In order to support nested heredoc
strings the *previous* heredoc label was assigned as the token value of
T_START_HEREDOC and the language_parser.y assigned that to CG(heredoc).
This created a dependency of the lexer on the parser. Thus the
token_get_all() function, which accesses the lexer directly without
also running the parser, was not able to tokenize nested heredoc strings
(and leaked memory). Same applies for the source-code highlighting
functions.
The new approach is to maintain a heredoc_label_stack in the lexer, which
contains all active heredoc labels.
As it is no longer required, T_START_HEREDOC and T_END_HEREDOC now don't
carry a token value anymore.
In order to make the work with zend_ptr_stack in this context more
convenient I added a new function zend_ptr_stack_top(), which retrieves the
top element of the stack (similar to zend_stack_top()).
# __TRAIT__ behaves like __CLASS__ more or less but is constraint to traits.
# Since traits are not types, there are not many valid use cases, and trying
# to use __TRAIT__ to make traits more like classes is discouraged.
# __TRAIT__ behaves like __CLASS__ more or less but is constraint to traits.
# Since traits are not types, there are not many valid use cases, and trying
# to use __TRAIT__ to make traits more like classes is discouraged.
# RFC http://wiki.php.net/rfc/horizontalreuse#traits_-_reuse_of_behavior
# Ok, here we go, I guess that will result in more discussion, which is fine
# by me. But now, the patch is here, and properly archived.
#
# See below a list of notes to the patch, it also includes a list of
# points which should be fixed
#
# Internals of the Traits Patch
# -----------------------------
#
# Open TODOs
# """"""""""
#
# - Reflection API
# - support for traits for internal classes
# - currently destroy_zend_class does not handle that case
#
# Introduced Structures
# """""""""""""""""""""
#
# Data structures to encode the composition information specified in the
# source:
# - zend_trait_method_reference
# - zend_trait_precedence
# - zend_trait_alias
#
# Changes
# """""""
#
# zend_class_entry
# - uses NULL terminated lists of pointers for
# - trait_aliases
# - trait_precedences
# - do you prefer an explicit counter?
# - the information is only necessary during class composition
# but might be interesting for reflection
# - did not want to blow up class further with not really necessary length counters
#
# added keywords
# - trait
# - insteadof
#
# Added opcodes
# ZEND_ADD_TRAIT
# - similar to ZEND_ADD_INTERFACE
# - adds the trait to the list of traits of a class, no actual composition done
# ZEND_BIND_TRAITS
# - emitted in zend_do_end_class_declaration
# - concludes the class definition and will initiate the trait composition
# when the class definition is encountered during runtime
#
# Added Flags
# ZEND_ACC_TRAIT = 0x120
# ZEND_ACC_IMPLEMENT_TRAITS = 0x400000
# ZEND_FETCH_CLASS_TRAIT = 14
#
# zend_vm_execute.h
# - not sure whether the handler initialization (ZEND_ADD_TRAIT_SPEC_HANDLER,
# ZEND_BIND_TRAITS_SPEC_HANDLER) is correct, maybe it should be more selective
#
# zend_compile.c
# - refactored do_inherit_method_check
# split into do_inherit_method_check and do_inheritance_check_on_method
# - added helper functions use a '_' as prefix and are not mentioned in the
# headers
# - _copy_functions
# prepare hash-maps of functions which should be merged into a class
# here the aliases are handled
# - _merge_functions
# builds a hash-table of the methods which need to be added to a class
# does the conflict detection
# - reused php_runkit_function_copy_ctor
# - it is not identical with the original code anymore, needed to update it
# think I fixed some bugs, not sure whether all have been reported back to runkit
# - has to be renamed, left the name for the moment, to make its origin obvious
# - here might be optimization potential
# - not sure whether everything needs to be copied
# - copying the literals might be broken
# - added it since the literals array is freed by efree and gave problems
# with doubled frees
# - all immutable parts of the zend_op array should not be copied
# - am not sure which parts are immutable
# - and not sure how to avoid doubled frees on the same arrays on shutdown
# - _merge_functions_to_class
# does the final merging with the target class to handle inherited
# and overridden methods
# - small helper for NULL terminated lists
# zend_init_list, zend_add_to_list
#
# zend_language_parser.y
# - reused class definition for traits
# - there should be something with regard to properties
# - if they get explicitly defined, it might be worthwhile to
# check that there are no collisions with other traits in a composition
# (however, I would not introduce elaborate language features to control that
# but a notice for such conflicts might be nice to the developers)
. ZEND_RECV now always has IS_CV as its result
. ZEND_CATCH now has to be used only with constant class names
. ZEND_FETCH_DIM_? may fetch array and dimension operans in a different order
. Improved syntax highlighting and consistency for variables in double-quoted strings and literal text in HEREDOCs and backticks. (Matt)
. Optimized interpolated strings to use one less opcode. (Matt)
[DOC] "expr1 ?: expr1" is a shortcut for: "expr1 ? expr1 : expr2" as
exists in gcc and discussed some time back. Note that this is not
an implementation ifsetor($var, default). While ifsetor would not
generate any message for non existing variables or array indices
the ternary shortcut does. Also the ternary shortcut does a boolean
evaluation rather then checking for isset(). That way ther ternary
shortcut can work on any expression while ifsetor can only work on
variables. Also to be silent one has do do: "@$expr1 ?: $expr2".
- Fixed bug #36214 (__get method works properly only when conditional operator is used).
- Fixed bug #39449 (Overloaded array properties do not work correctly).
- Fixed bug #39990 (Cannot "foreach" over overloaded properties).
# This time i added:
# ZEND_FE_RESET_VARIABLE
# ZEND_FE_RESET_REFERENCE
# and dapted parser,compiler,executor,interfaces to handle these flags
# their purpose is to be able to pass whetehr foreach is done by ref to
# the current() handler so that it can error out in case it is not capable
# to comply to the requested return signature/protocol/semantics (weyp).
- Extensions which delete global variables need to use new special function
- delete_global_variable() (I'm about to rename it) to remove them.
- Will post to internals@ or via commit messages if there's anything else.
Note that this is available for downwards compatibility only - and it doesn't
work if you use new features (namely, interfaces). Generally, people should
declare their classes before using them, but we just didn't want hell to break
loose (c)
implementation, and allows exceptions to 'fire' much earlier than before.
Instructions on how to use the new mechanism will follow on internals@
shortly...
Note - this (most probably) breaks the current implementation of
set_exception_handler()
implementation.
Using clone directly is now done using
$replica = clone $src;
Clone methods must now be declared as follows:
function __clone($that)
{
}
Clone methods in derived classes can call the __clone method of their parent
classes using parent::__clone($that)
- declerations. Allowing the access of other constants in this code is
- flawed. We are reverting back to PHP 4's static scalars.
- Don't worry if you get the following msg when compiling:
- "zend_language_parser.y contains 3 useless nonterminals and 22 useless rules"
- I didn't nuke the code in case we have some brilliant ideas after beta 2
including:
- Whether or not to pass by ref (replaces the old arg_types, with arg_info)
- Argument name (for future use, maybe introspection)
- Class/Interface name (for type hints)
- If a class/interface name is available, whether to allow a null instance
Both user and builtin functions share the same data structures.
To declare a builtin function that expects its first arg to be an instance
of class 'Person', its second argument as a regular arg, and its third by
reference, use:
ZEND_BEGIN_ARG_INFO(my_func_arg_info, 0)
ZEND_ARG_OBJ_INFO(0, someone, Person, 1)
ZEND_ARG_PASS_INFO(0)
ZEND_ARG_PASS_INFO(1)
ZEND_END_ARG_INFO();
and use my_func_arg_info as the arg_info parameter to the ZEND_FE() family
of macros.
The first arg to each ZEND_ARG_*() macro is whether or not to pass by ref.
The boolean arg to ZEND_BEGIN_ARG_INFO() tells the engine whether to treat
the arguments for which there's no explicit information as pass by reference
or not.
The boolean argument to ZEND_ARG_OBJ_INFO() (4th arg) is whether or not to allownull values.
- The fields of zend_namespace were not completely initialized which
led to a variety of problems.
- The occurrence of class/interface/namespace definition is now
captured.
- Functions/classes/interfaces/namespaces can be preceded by doc
comments which are stored for use by extensions.
avoid making developers traverse the entire class/interface hierarchy
before they can figure out whether a class is instantiable
(ok, so it makes sense :)
1. Nested classes are gone.
2. New syntax for namespaces:
namespace foo {
class X { ... }
function bar { ... }
var x = 1;
const ZZ = 2;
}
3. Namespaced symbol access: $x = new foo::X; - etc.
For now, namespaces are case insensitive, just like classes.
Also, there can be no global class and namespace with the same name
(to avoid ambiguities in :: resolution).
NOTE: This only works at the syntax level right now (parser). It
doesn't actually work as of yet - all statics are considered
public for now
- Prevent users from putting more restrictions on methods in derived classes
(i.e., you cannot make a public method private in a derived class, etc.)
- Implement abstract methods, syntax:
- abstract function foo($vars);
- I don't see any reason why modifiers such as static/public need to be
- used with abstract. PHP is weakly typed and there would be no meaning to
- this anyway. People who want a strictly typed compiled language are
- looking in the wrong place.
- some fixes by me).
- You can't access protected variables from outside the object. If you want
- to see a protected member from your ancestors you need to declare the
- member as protected in the class you want to use it in. You can't
- redeclare a protected variable as private nor the other way around.
- understand why Java didn't do so.
- If you still want to control destruction of your object then either make
- sure you kill all references or create a destruction method which you
- call yourself.
- Change zval's refcount to zend_uint (If it doesn't slow down the Engine
- too much it should probably stay this way). If anyone has time to test
- the difference in speed between zend_ushort & zend_uint in zend.h of
- the struct _zval_struct (one line change) I'd be glad to get some
- figures.
- It isn't complete yet but I want to work on it from another machine. It
- shouldn't break anything else so just don't try and use it.
- The following is a teaser of something that already works:
<?php
class MyClass
{
function hello()
{
print "Hello, World\n";
}
class MyClass2
{
function hello()
{
print "Hello, World in MyClass2\n";
}
}
}
import function hello, class MyClass2 from MyClass;
MyClass2::hello();
hello();
?>
