LiveCode

Description

The LiveCode software creates applications that run in many supported environments, using a compile-free workflow. The same computer code in LiveCode can play across multiple devices and platforms. LiveCode uses a high level, English-like programming language called Transcript that is dynamically typed. Transcript and compile-free workflow generates code that is self-documenting and easy for casual programmers to comprehend. For example, if the following script was executed when the system clock was at 9:00:00 AM:

  repeat ten times
    put "Hello world at" && the long time & return after field 1
    wait 1 second
  end repeat

Ten lines will be loaded into the first text field. (denoted as "field 1"), and seen as:

Hello world at 9:00:00 AM
Hello world at 9:00:01 AM
Hello world at 9:00:02 AM
...

Notes:

• repeat (and the associated end repeat) is a control structure, illustrated here in just one of its various forms.
• put is a command
• "Hello World at" is a literal
• the long time is a function that calls the system time
• return is a constant equal to ASCII character 10 (linefeed)
• after is a keyword that is involved with an extremely powerful and intuitive system known as "chunking", a hallmark of xTalk languages.
• field 1 is an object reference, here denoted by the layer number of a text field. Almost all standard object classes are supported, and may be referred to in several, highly-intuitive ways.

LiveCode's natural English-like syntax is easy for beginners to learn. Variables are typeless, and are typed at compile time based purely on context. This makes the language simple to read and maintain, with relatively minimal loss of speed. The language contains advanced features including associative arrays,^[14]regular expressions, multimedia, support for a variety of SQL databases, and TCP/IP libraries. The LiveCode engine supports several common image formats (including BMP, PNG, GIF, and JPEG,), anti-aliased vector graphics, HTML-style text hyperlinks, chained behaviors and embedded web browsers. Accessing these higher-level functions is designed to be straightforward.

Examples

• To load the source code of a web page into a variable takes one line of code:

put url "http://www.wikipedia.com" into MyVariable

• Uploading a file to an FTP server uses similar syntax:

put url "binfile:picture.jpg" into url "ftp://john:[email protected]:2121/picture.jpg"

Depth

LiveCode has around 2,950 built-in language terms and keywords, which may be extended by external libraries written in C and other lower level languages.^[15][16]

Outcomes

LiveCode project files are binary-compatible across platforms. They inherit each platform's look-and-feel and behaviors. Buttons, scroll bars, progress bars and menus behave as expected on the target platform without any intervention on the part of the one authoring a LiveCode application.

Compiling a LiveCode "standalone" produces a single, executable file (minimum size ~1.5MB) for each platform targeted. There is no separate runtime necessary.

The Wikipedia article on HyperCard contains a more detailed discussion about the basics of a similar development environment and scripting language. Modern LiveCode is a vast superset of the former HyperCard yet retains its simplicity. LiveCode includes a number of features missing from the original HyperCard program, including multiple platform deployment, communication with external devices and many fundamental language extensions. The LiveCode toolkit, as compared to HyperCard, has the ability to access internet-based text and media resources, which allows the creation of internet-enabled desktop applications.^[17]

Compatibility

iOS and Android targets are available in some versions.

Note: Complete Linux requirements for 4.5.x-6.x are the following:

• 32-bit installation, or a 64-bit linux distribution that has a 32-bit compatibility layer
• 2.4.x or later kernel
• X11R5 capable Xserver running locally on a 24-bit display
• glibc 2.3.2 or later
• gtk/gdk/glib (optional – required for native theme support)
• pango/xft (optional – required for pdf printing, anti-aliased text and unicode font support)
• lcms (optional – required for color profile support in JPEGs and PNGs)
• gksu (optional – required for elevate process support)

See also

• MetaCard, Runtime Revolution acquired the MetaCard technology, on which its development system is based, in 2003.
• HyperCard, Progenitor of all xTalk languages.

References

Bibliography

External links

• Official website