OnlineWoerterBuecher.de - Lexikon, Free On-line Dictionary of Computing



	OnlineWoerterBuecher.de

Navigation

Start

Deutsch-Englisch

Deutsch-Spanisch

Enzyklopädie

Internes

Impressum

Kontakt

Lexikon

Liana

A href="module.php?name=Lexikon&file=search&eid=1&query=C">C-like, interpretive, {object-oriented programming} language, {class} library, and integrated development environment designed specifically for development of href="module.php?name=Lexikon&file=search&eid=1&query=application programs">application programs for href="module.php?name=Lexikon&file=search&eid=1&query=Microsoft Windows">Microsoft Windows and {Windows NT}. Designed by Jack Krupansky of href="module.php?name=Lexikon&file=search&eid=1&query=Base Technology">Base Technology, Liana was first released as a commercial product in August 1991. The language is designed to be as easy to use as href="module.php?name=Lexikon&file=search&eid=1&query=BASIC">BASIC, as concise as href="module.php?name=Lexikon&file=search&eid=1&query=C">C, and as flexible as href="module.php?name=Lexikon&file=search&eid=1&query=Smalltalk">Smalltalk. The href="module.php?name=Lexikon&file=search&eid=1&query=OOP">OOP href="module.php?name=Lexikon&file=search&eid=1&query=syntax">syntax of href="module.php?name=Lexikon&file=search&eid=1&query=C++">C++ was chosen over the less familiar syntax of href="module.php?name=Lexikon&file=search&eid=1&query=Smalltalk">Smalltalk and href="module.php?name=Lexikon&file=search&eid=1&query=Objective-C">Objective-C to appeal to href="module.php?name=Lexikon&file=search&eid=1&query=C">C programmers and in recognition of C++ being the leading OOP language. The syntax is a simplified subset of href="module.php?name=Lexikon&file=search&eid=1&query=C/C++">C/C++. The href="module.php?name=Lexikon&file=search&eid=1&query=semantics">semantics are also a simplified subset of C/C++, but extended to achieve the flexibility of Smalltalk. Liana is a typeless language (like href="module.php?name=Lexikon&file=search&eid=1&query=Lisp">Lisp, href="module.php?name=Lexikon&file=search&eid=1&query=Snobol">Snobol and href="module.php?name=Lexikon&file=search&eid=1&query=Smalltalk">Smalltalk), which means that the datatypes of variables, function parameters, and function return values are not needed since values carry the type information. Hence, variables are simply containers for values and function parameters are simply pipes through which any type of value can flow. href="module.php?name=Lexikon&file=search&eid=1&query=Single inheritance">Single inheritance, but not href="module.php?name=Lexikon&file=search&eid=1&query=multiple inheritance">multiple inheritance, is supported. href="module.php?name=Lexikon&file=search&eid=1&query=Memory management">Memory management is automatic using {reference counting}. The library includes over 150 href="module.php?name=Lexikon&file=search&eid=1&query=classes">classes, for href="module.php?name=Lexikon&file=search&eid=1&query=dynamic arrays">dynamic arrays, href="module.php?name=Lexikon&file=search&eid=1&query=associative lookup">associative lookup tables, windows, menus, dialogs, controls, bitmaps, cursors, icons, mouse movement, keyboard input, fonts, text and graphics display, href="module.php?name=Lexikon&file=search&eid=1&query=DDE">DDE, and href="module.php?name=Lexikon&file=search&eid=1&query=MDI">MDI. Liana provides flexible OOP support for Windows programming. For example, a href="module.php?name=Lexikon&file=search&eid=1&query=list box">list box automatically fills itself from an associated href="module.php?name=Lexikon&file=search&eid=1&query=object">object. That object is not some sort of special object, but is merely any object that "behaves like" an array (i.e., has a "size" member function that returns the number of elements, a "get" function that returns the ith element, and the text for each element is returned by calling the "text" member function for the element). A related product, C-odeScript, is an embeddable application scripting language. It is an implementation of Liana which can be called from C/C++ applications to dynamically evaluate expressions and statement sequences. This can be used to offer the end-user a macro/scripting capability or to allow the C/C++ application to be customized without changing the C/C++ source code. Here' s a complete Liana program which illustrates the flexibility of the language semantics and the power of the class library: main { // Prompt user for a string. // No declaration needed for "x" (becomes a global variable.) x = ask ("Enter a String") // Use "+" operator to concatenate strings. Memory // management for string temporaries is automatic. The // "message" function displays a Windows message box. message ("You entered: " + x) // Now x will take on a different type. The "ask_number" // function will return a "real" if the user' s input // contains a decimal point or an "int" if no decimal // point. x = ask_number ("Enter a Number") // The "+" operator with a string operand will // automatically convert the other operand to a string. message ("You entered: " + x) // Prompt user for a Liana expression. Store it in a // local variable (the type, string, is merely for // documentation.) string expr = ask ("Enter an Expression") // Evaluate the expression. The return value of "eval" // could be any type. The "source_format" member function // converts any value to its source format (e.g., add // quotes for a string.) The "class_name" member function // return the name of the class of an object/value. // Empty parens can be left off for member function calls. x = eval (expr) message ("The value of " + expr + " is " + x.source_format + " its type is " + x.class_name) } The author explained that the "Li" of Liana stands for "Language interpreter" and liana are vines that grow up trees in tropical forests, which seemed quite appropriate for a tool to deal with the complexity of MS Windows! It is also a woman' s name. ["Liana for Windows", Aitken, P., PC TECHNIQUES, Dec/Jan 1993]. ["Liana: A Language For Writing Windows Programs", Burk, R., Tech Specialist (R&D Publications), Sep 1991]. ["Liana v. 1.0." Hildebrand, J.D., Computer Language, Dec 1992]. ["Liana: A Windows Programming Language Based on C and C++", Krupansky, J., The C Users Journal, Jul 1992]. ["Writing a Multimedia App in Liana", Krupansky, J., Dr. Dobb' s Journal, Winter Multimedia Sourcebook 1994]. ["The Liana Programming Language", R. Valdes, Dr Dobbs J Oct 1993, pp.50-52]. (1999-06-29)

[ Go Back ]

Free On-line Dictionary of Computing

	All logos and trademarks in this site are property of their respective owner. Page Generation in 0.1244 Seconds, with 16 Database-Queries