Xmlb.Machine¶

Subclasses:: None

Methods¶

Inherited:: GObject.Object (37)
Structs:: GObject.ObjectClass (5)

class	`new` ()
	`add_method` (name, n_opcodes, method_cb, *user_data)
	`add_opcode_fixup` (opcodes_sig, fixup_cb, *user_data)
	`add_operator` (str, name)
	`add_text_handler` (handler_cb, *user_data)
	`get_stack_size` ()
	`opcode_func_init` (func_name)
	`parse` (text, text_len)
	`parse_full` (text, text_len, flags)
	`run` (opcodes, exec_data)
	`run_with_bindings` (opcodes, bindings, exec_data)
	`set_debug_flags` (flags)
	`set_stack_size` (stack_size)
	`stack_pop` (stack)
	`stack_push` (stack)
	`stack_push_integer` (stack, val)
	`stack_push_text` (stack, str)
	`stack_push_text_static` (stack, str)
	`stack_push_text_steal` (stack, str)

Virtual Methods¶

Inherited:: GObject.Object (7)

Properties¶

None

Signals¶

Inherited:: GObject.Object (1)

Fields¶

Inherited:: GObject.Object (1)

Name	Type	Access	Description
parent_instance	`GObject.Object`	r

Class Details¶

class Xmlb.Machine(**kwargs)¶

Bases:: GObject.Object
Abstract:: No
Structure:: Xmlb.MachineClass

classmethod new()¶

Returns:: a new Xmlb.Machine
Return type:: Xmlb.Machine

Creates a new virtual machine.

New in version 0.1.1.

add_method(name, n_opcodes, method_cb, *user_data)¶

Parameters:

name (str) – function name, e.g. contains
n_opcodes (int) – minimum number of opcodes required on the stack
method_cb (Xmlb.MachineMethodFunc) – function to call
user_data (object or None) – user pointer to pass to method_cb, or None

Adds a new function to the virtual machine. Registered functions can then be used as methods.

The method_cb must not modify the stack it’s passed unless it’s going to succeed. In particular, if a method call is not optimisable, it must not modify the stack it’s passed.

You need to add a custom function using Xmlb.Machine.add_method() before using methods that may reference it, for example Xmlb.Machine.add_opcode_fixup().

New in version 0.1.1.

add_opcode_fixup(opcodes_sig, fixup_cb, *user_data)¶

Parameters:

opcodes_sig (str) – signature, e.g. INTE,TEXT
fixup_cb (Xmlb.MachineOpcodeFixupFunc) – callback
user_data (object or None) – user pointer to pass to fixup_cb

Adds an opcode fixup. Fixups can be used to optimize the stack of opcodes or to add support for a nonstandard feature, for instance supporting missing attributes to functions.

New in version 0.1.1.

add_operator(str, name)¶

Parameters:

str (str) – operator string, e.g. ==
name (str) – function name, e.g. contains

Adds a new operator to the virtual machine. Operators can then be used instead of explicit methods like eq().

You need to add a custom operator using Xmlb.Machine.add_operator() before using Xmlb.Machine.parse(). Common operators like <= and = are built-in and do not have to be added manually.

New in version 0.1.1.

add_text_handler(handler_cb, *user_data)¶

Parameters:

handler_cb (Xmlb.MachineTextHandlerFunc) – callback
user_data (object or None) – user pointer to pass to handler_cb

Adds a text handler. This allows the virtual machine to support nonstandard encoding or shorthand mnemonics for standard functions.

New in version 0.1.1.

get_stack_size()¶

Returns:: integer
Return type:: int

Gets the maximum stack size used for the machine.

New in version 0.1.3.

opcode_func_init(func_name)¶

Parameters:

func_name (str) – function name, e.g. eq

Returns:

True if the function was found and the opcode initialised, False otherwise

opcode:: a stack allocated Xmlb.Opcode to initialise

Return type:

(bool, opcode: Xmlb.Opcode)

Initialises a stack allocated Xmlb.Opcode for a registered function. Some standard functions are registered by default, for instance eq or ge. Other functions have to be added using Xmlb.Machine.add_method().

New in version 0.2.0.

parse(text, text_len)¶

Parameters:

text (str) – predicate to parse, e.g. contains(text(),'xyx')
text_len (int) – length of text, or -1 if text is NUL terminated

Raises:

GLib.Error

Returns:

opcodes, or None on error

Return type:

Xmlb.Stack

Parses an XPath predicate. Not all of XPath 1.0 or XPath 1.0 is supported, and new functions and mnemonics can be added using Xmlb.Machine.add_method() and Xmlb.Machine.add_text_handler().

New in version 0.1.1.

parse_full(text, text_len, flags)¶

Parameters:

text (str) – predicate to parse, e.g. contains(text(),'xyx')
text_len (int) – length of text, or -1 if text is NUL terminated
flags (Xmlb.MachineParseFlags) – Xmlb.MachineParseFlags, e.g. Xmlb.MachineParseFlags.OPTIMIZE

Raises:

GLib.Error

Returns:

opcodes, or None on error

Return type:

Xmlb.Stack

Parses an XPath predicate. Not all of XPath 1.0 or XPath 1.0 is supported, and new functions and mnemonics can be added using Xmlb.Machine.add_method() and Xmlb.Machine.add_text_handler().

New in version 0.1.4.

run(opcodes, exec_data)¶

Parameters:

opcodes (Xmlb.Stack) – a Xmlb.Stack of opcodes
exec_data (object or None) – per-run user data that is passed to all the Xmlb.MachineMethodFunc functions

Raises: