b2l-tools/lgi/docs/reference.md

LGI Core Reference

Core

Core LGI functionality is accessible through lgi module, loaded by require 'lgi' command. LGI does not install itself into global namespace, caller has to use the return value from require call.

• lgi.'module'
  • module string with module name, e.g.'Gtk' or 'WebKit'.

Loads requested module of the latest version found into the repository.

• lgi.require(module, version)
  • module string with module name, e.g. 'Gtk' or 'WebKit'.
  • version string with exact required version of the module

Loads requested module with specified version into the repository.

• lgi.log.domain(name)

  • name is string denoting logging area name, usually identifying the application or the library
  • return table containing
  • message
  • warning
  • critical
  • error
  • debug

  methods for logging messages. These methods accept format string and inserts, which are formatted according to Lua's string.format conventions.

• lgi.yield() when called, unlocks LGI state lock, for a while, thus allowing potentially blocked callbacks or signals to enter the Lua state. When using LGI with GLib's MainLoop, this call is not needed at all.

GObject basic constructs

GObject.Type

• NONE, INTERFACE, CHAR, UCHAR, BOOLEAN, INT, UINT, LONG, ULONG, INT64, UINT64, ENUM, FLAGS, FLOAT, DOUBLE, STRING, POINTER, BOXED, PARAM, OBJECT, VARIANT
  

Constants containing type names of fundamental GObject types.

• parent, depth, next_base, is_a, children, interfaces, query, fundamental_next, fundamental
  

Functions for manipulating and querying GType. THey are direct mappings of g_type_xxx() APIs, e.g. GObject.Type.parent() behaves in the same way as g_type_parent() in C.

GObject.Value

• GObject.Value([gtype [, val]])
  • gtype type of the vlue to create, if not specified, defaults to GObject.Type.NONE.
  • val Lua value to initialize GValue with.

Creates new GObject.Value of specified type, optionally assigns Lua value to it. For example, local val = GObject.Value(GObject.Type.INT, 42) creates GValue of type G_TYPE_INT and initializes it to value 42.

• GObject.Value.gtype

  • reading yields the gtype of the value
  • writing changes the type of the value. Note that if GValue is already initialized with some value, a g_value_transform is called to attempt to convert value to target type.

• GObject.Value.value

  • reading retrieves Lua-native contents of the referenced Value (i.e. GValue unboxing is performed).
  • writing stores Lua-native contents to the Value (boxing is performed).

GObject.Closure

• GObject.Glosure(func)
  • target is Lua function or anything Lua-callable.

Creates new GClosure instance wrapping given Lua callable. When the closure is emitted, target function is invoked, getting GObject.Value instances as arguments, and expecting single GObject.Value to be returned.