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- True BASIC is a variant of the BASIC programming language descended from Dartmouth BASIC – the original BASIC – invented by college professors John G. Kemeny and Thomas E. Kurtz. When True BASIC appeared on the market in 1985, initially based on Dartmouth BASIC 7—otherwise known as ANSI BASIC—it implemented a number of new features over QBasic, and allowed the user a redefinable 16-color, 640×480 pixel backdrop for program editing. True BASIC introduced new functions for graphics primitives like plot, plot area, flood, etc. It also was the first to provide a method for saving a portion of the screen and blitting it elsewhere, but had no proper buffering implementation. Being a structured programming implementation of the language, it dispensed with the need for line numbers and GOTO statements, although these earlier features can still be used. Use of LET for value assignment became optional. It also allowed for descriptive variable names longer than a single letter plus a single digit. For example, the familiar algebraic equation y = mx + b (y = mx + c for the UK) could be expressed as: let slope = 2 let x = 3 let y_intercept = 4 let y2 = slope * x + y_intercept print "y2="; y2 end The above code segment would yield "y2= 10". True BASIC provides statements for matrix arithmetic, a feature that had been dropped in microcomputer versions of BASIC interpreters due to memory limitations. It also supports global and local variables, which permits recursive functions and subroutines to be written. There are versions of the True BASIC compiler for DOS, Windows, and Classic Mac OS. There is currently no Mac OS X version of True BASIC, and so it will not run on Intel-based Macintoshes, nor any Macintosh running Mac OS X 10.5 Leopard. At one time, versions for Tandy, Amiga and Atari computers were offered. The designers wanted to make the language hardware-independent, to allow True BASIC source code to run equally well on any version of their compiler. For the most part they succeed in this endeavor. The drawback for users was that direct access to some features of their machines was not available, but this could be remedied with callable functions and subroutines specially written in assembly language. Using newer versions of True BASIC, some of the older functions are blocked out. An example of the recent code would be more like this (Note that any exclamation point after text means that anything to the right of the exclamation point is a comment, meaning that the compiler doesn't read it): RANDOMIZE SET WINDOW 0,20,0,20 SET COLOR 132 !Set the pen and text color to 132 PRINT "Welcome To . . . " !Print "Welcome To . . . " on the user's screen DO !Begin the loop LET x=rnd*20 !Let the value 'x' equal a random number between '0' and '20' LET y=rnd*20 !Let the value 'y' equal a random number between '0' and '20' Pause .1 !Waits 1/10 of a second PLOT TEXT, at x, y: "Fabulous Wikipedia!" !Plot 'Fabulous Wikipedia!' at the coordinates set by our random 'x' and 'y' LOOP !End the loop END !End the program As you can see, even without comments, True BASIC code can be read rather easily. This simple program plots the text "Welcome To . . . " at the top left-hand corner of the screen, and then continues into a never-ending loop plotting "Fabulous Wikipedia!" at random coordinates. An example of simple animation could be like this: !Draw the Car SET WINDOW 0,20,0,20 SET COLOR 5 BOX AREA 2,6,2,3 BOX AREA 9,13,2,3 BOX AREA 16,20,2,3 SET COLOR 249 PLOT LINES :0,5;20,5 FLOOD 10,1 BOX KEEP 0,20,0,5 IN road$ BOX CIRCLE 2,3,5,6 FLOOD 2.5,5.5 BOX CIRCLE 5,6,5,6 FLOOD 5.5,5.5 SET COLOR 35 PLOT LINES :2.5,6;5.5,6 PLOT LINES :5,6;8,6;8,8;6,8;6,10;2,10;2,8;0,8;0,6;3,6 FLOOD 4,8 SET COLOR 248 BOX AREA 4,5,8,9 BOX KEEP 0,8,5,10 IN car$ !Save the car in 'car$' FOR x=1 TO 20 STEP 1 !Create a 'for' loop BOX SHOW road$ AT 0,0 BOX SHOW car$ AT x,5 PAUSE .1 CLEAR NEXT x !End the 'for' loop END !End the programs
- Das erste BASIC wurde 1963 von den Professoren Thomas E. Kurtz und John G. Kemeny am Dartmouth College (USA) entwickelt. Ihr Ziel war es, ihren Studenten die Arbeit am Computer näher zu bringen und eine leichter zu erlernende Alternative zu den wesentlich mächtigeren Programmiersprachen ALGOL und FORTRAN zu entwickeln. Am 1. Mai 1964 wurde das erste BASIC-Programm auf einem Großcomputer vom Typ GE 225 gestartet. Der reduzierte Funktionenumfang und die leichte Erlernbarkeit von BASIC machte es hervorragend geeignet zur Implementierung auf Home- und Personalcomputern. Der wirtschaftliche Erfolg brachte aber auch zahlreiche Varianten und Dialekte hervor, die mit dem Verständnis einer einheitlichen Sprache nicht vereinbar waren. Dies war wohl mit ein Grund dafür, warum die beiden Entwickler nach der Sprachdefinition selbst noch Jahrzehnte später 'das wahre BASIC' namens TrueBasic als Entwicklungswerkzeug auf den Markt brachten. True BASIC spielt heute sowohl bei professionellen Entwicklern als auch bei Hoppyprogrammieren praktisch keine Rolle mehr. Es existieren Konverter von BASIC- und FORTRAN-Quellecodes zu TrueBasic.
- True BASIC è una delle varianti del linguaggio di programmazione BASIC. Discende dal Dartmouth BASIC, il primo linguaggio BASIC inventato dai professori John G. Kemeny e Thomas E. Kurtz. Quando True BASIC uscì nel 1985, era basato inizialmente sul Dartmouth BASIC 7 (noto anche come ANSI BASIC) e aveva più caratteristiche rispetto al QBASIC. True BASIC introdusse nuove funzioni grafiche come plot, plot area, flood, ecc. Per primo, dava la possibilità di salvare una porzione dello schermo e di usare l'operazione di blitting, ma senza gestione del buffering. True BASIC rispetta i principi della programmazione strutturata; quindi non è obbligatorio utilizzare numeri di linea e istruzioni GOTO. L'uso dell'istruzione LET divenne opzionale; essa permetteva l'uso di nomi descrittivi per le variabili. Ad esempio, l'equazione algebrica y = mx + b poteva essere scritta come: slope = 2 let x = 3 y_intercept = 4 let y2 = slope * x + y_intercept print "y2="; y2 True BASIC era forinto di funzioni per l'aritmetica delle matrici. Supportava anche le variabili locali e globali e l'uso di funzioni ricorsive, una caratteristica non disponibile in nessun altro linguaggio BASIC di quei tempi. True BASIC uscì per il DOS, Windows, Mac OS, Linux, sistemi Unix, Tandy Radio Shack TRS-80, Amiga ed Atari. I progettatori volevano rendere il linguaggio indipendente dall'hardware, per permettere di eseguire il codice BASIC su qualsiasi piattaforma. Lo svantaggio per i programmatore era l'impossibilità di utilizzare alcune caratteristiche peculiari del computer che stavano utilizzando. Per aggirare questo problema, si potevano scrivere funzioni in linguaggio assembly.
- True BASIC是BASIC的一種，由原來的BASIC作者约翰·凯梅尼及托马斯·卡茨兩位教授所創立。他們有感自從BASIC這種編程語言在微電腦上風行以來，其設計都與原來BASIC的設計逐漸偏離，所以他們希望可以透過這一套True BASIC語言來重新強調BASIC語言所應有的設計特色，使到原來為迷你電腦及小型電腦設計的BASIC程序可以更好地移殖到微機上使用。巧合地，當時所風行的各個BASIC版本，不論是蘋果電腦的Applesoft BASIC或MS-DOS的GWBASIC或Quick BASIC，都是由微軟所開發的。就連第一套編譯式的BASIC版本、Borland的Turbo BASIC，也是基於微軟的GW-BASIC語言。
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