This is just to let you know that the lastest version Dao language is
This Dao was previously called Tao, and now is changed to Dao to avoid
with another Tao langauge. There are a number of new features
this version, of which the most important one is the supporting for
programming. A new concurrent garbage collector is also implemented to
multi-threaded interpreter. Now unicode is also supported for string
and regular expression (regex) matching etc. The algorithm for regex
is enhanced with fixing of a few bugs which prevent finding the most
matching in some case, and allowing reverse matching from the end of
The interface for creating Dao plugin in C++ is further simplified and
Of course, many bugs are also fixed. For more information,
please visite: http://www.xdao.org.
By the way, a console named DaoConsole with graphical user interface is
With best regards,
ChangLog for this release:
- : added
! : changed
- : fixed
- : removed
- Multi-threaded programming is supported as a kernel feature of
Dao language. Posix thread library is used in the implementation.
And the thread API in Dao is similar to that in Posix thread.
Parts of the Dao interpreter is re-structured for multithreading.
- A novel concurrent garbage collector based on reference counting
is implemented to support multithreading.
- A upper bound for GC amount is applied to prevent memory “avalanche”,
where mutators generate garbage faster than GC can collect them.
- UNICODE is supported. String quotated with double quotation symbol
is internally represented as Wide Character String(WCS), while string
quotated with single quotation symbol is internally represented
Multi Bytes String(MBS). Corresponding operations on WCS is also
- Regex reverse matching is supported.
- Now internal representation of Regex uses both MBS and WCS for both
efficiency and proper matching character class for unicode. When a
regex is applied to MBS or WCS, the corresponding representation is
- Regex datatype is added, a regex pattern can be compiled and stored
for later use, by using: define regex: rgx = /\d+\w/;
or, rgx = regex( “\d+\w” );
- New character class abbreviations \u and \U are added for unicode.
- Customized character class abbreviations are support. Users can
their own character class abbreviations by:
define regex: \2 = [WhateverChars];
! Algorithm for regex matching is modified to extend matching when
possible, and is also modified to match regex group correctly.
- Specification of precision in numeric array enumeration is supported:
! Transpose operator(right operator) is changed from ’ to ~.
- Function convolute() for numeric arrays is removed.
EXTENDING AND EMBEDDING:
- Some abstract classes are added for supporting easy embedding
of Dao interpreter ( the daoMain.cpp source file is an example
for embedding ).
- Some wrapper classes for Dao data objects are provide in daoType.h
to faciliate the using of Dao data objects in plugins or other
programs in which Dao is embedded.
! A new technique is implemented to allow more tranparent passing
data between Dao interpreter and C++ modules. Creation of shadow
classes is also supported by the way.
- Instead of using STL stream classes, new DaoStream classes are
added mainly for handling unicode in many places.
- For file IO, more open modes such as “rwat” are supported, and
more methods such as eof(), seek(), tell() … are implemented.
read() is enhanced such that it can read until meeting EOF.
- Multi inheritance is supported for OOP. And the passing parameters
and calling to parent constructor is simplified.
- Negative subindex is supported for string.
- Added a feature that allows using Alternate KeyWord (*.akw) to
write Dao scripts in non-english languages. The only requirement
is the character encoding for the .akw file must be the same as the
! Variable scope specification keyword “global” is added; keyword
“extern” is remove; keyword “share” is changed to “shared”
! Data states are added for constant and frozen data. Now a const
data is a really const, and can not be modified anymore. Function
freeze() is added to freeze some data structures as well as those
are reachable from them, to prevent them from being modified;
And defreeze() is added to defreeze them.
! The using namespace is simplified(compile(),eval(),source()).