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| True BASIC | |
|---|---|
 | |
| Designed by | John G. Kemeny Thomas E. Kurtz |
| Developer | True BASIC, Inc. |
| First appeared | 1983; 43 years ago (1983) |
| Website | www |
| Influenced by | |
| BASIC | |
True BASIC is a variant of theBASIC programming language descended fromDartmouth BASIC — the original BASIC. Both were created by college professorsJohn G. Kemeny andThomas E. Kurtz.[1]
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True BASIC traces its history to an offshoot ofDartmouth BASIC called Structured BASIC, orSBASIC for short. This was released sometime in 1975 or 1976, but was not installed as the mainline version of BASIC on theDartmouth Time-Sharing System (DTSS) that supported the campus. Shortly after, Kemeny became involved in an effort to produce anANSI standard BASIC in an attempt to bring together the many small variations of the language that had developed through the late 1960s and early 1970s. This effort initially focused on a system known asMinimal BASIC that was similar to earliest versions of Dartmouth BASIC, while later work was aimed at aFull BASIC that was essentially SBASIC with various extensions.
By the early 1980s, tens of millions ofhome computers were running some variation ofMicrosoft BASIC, which had become thede facto standard. The ANSI efforts eventually became pointless, as it became clear that these versions were not going to have any market impact in a world dominated by Microsoft. Both versions were eventually ratified but saw little or no adoption and the standards were later withdrawn. Kemeny and Kurtz, however, decided to continue their efforts to introduce the concepts from SBASIC and the ANSI Standard BASIC efforts. This became True BASIC.
Initially based on Dartmouth BASIC 7, True BASIC was introduced in 1985. There are versions of the True BASICcompiler forMS-DOS,Microsoft Windows, andClassic Mac OS. At one time, versions forTRS-80 Color Computer,Amiga andAtari ST computers were offered, as well as aUNIX command-line compiler.
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Being astructured programming implementation of the language, it dispenses with the need forline numbers andGOTO statements, although these can still be used.
True BASIC provides statements formatrix arithmetic, a feature that had been present in Dartmouth BASIC since early times, but had been dropped in almost allmicrocomputer versions ofBASIC interpreters. It implementsglobal andlocal variables which make it possible to writerecursive functions andsubroutines.
The designers wanted to make the language hardware-independent, so True BASICsource code would run equally well on any version of their compiler.[citation needed] 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 inassembly 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:
RANDOMIZESETWINDOW0,20,0,20SETCOLOR5!Setthepenandtextcolourto5astruebasichas0-15coloursPRINT"Welcome To ..."!Print"Welcome To ..."ontheuser's screen.DO!BegintheloopLETx=rnd*20!Letthevalue'x' equal a random number between '0' and '20'LETy=rnd*20!Letthevalue'y' equal a random number between '0' and '20'Pause.1!Waits1/10ofasecondPLOTTEXT,atx,y:"Fabulous Wikipedia!"!Plot'Fabulous Wikipedia!' at coordinates 'x' and 'y'LOOP!EndtheloopEND!Endtheprogram
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:
!DrawtheCarSETWINDOW0,20,0,20SETCOLOR5BOXAREA2,6,2,3BOXAREA9,13,2,3BOXAREA16,20,2,3SETCOLOR249PLOTLINES:0,5;20,5FLOOD10,1BOXKEEP0,20,0,5INroad$BOXCIRCLE2,3,5,6FLOOD2.5,5.5BOXCIRCLE5,6,5,6FLOOD5.5,5.5SETCOLOR35PLOTLINES:2.5,6;5.5,6PLOTLINES:5,6;8,6;8,8;6,8;6,10;2,10;2,8;0,8;0,6;3,6FLOOD4,8SETCOLOR248BOXAREA4,5,8,9BOXKEEP0,8,5,10INcar$!Savethecarin'car$'FORx=1TO20STEP1!Createa'for' loopBOXSHOWroad$AT0,0BOXSHOWcar$ATx,5PAUSE.1CLEARNEXTx!Endthe'for' loopEND!Endtheprograms
Jerry Pournelle in 1985 asked, "why do we need True BASIC at all? [It] doesn't seem to do anything regular BASIC doesn't do, and what it does do isn't attacked in a logical or intuitive manner." He criticized the lack of output when encountering an error, preventing interactive debugging by "inserting print statements as diagnostics". Pournelle concluded, "I think I'll pass up the opportunity to become a born-again True BASIC believer. I'll enjoy myMicrosoft andCBASIC heresies."[2]
Some users have complained about their programs and the editor using up 100% of theirCPU (orcore).[3][4][5][6] This appears to be caused by the editor and user's programs using a loop which constantlypolls the keyboard and mouse for events. The problem has been known since at least the end of 2010,[3] yet as of early 2014 is still being worked on.[6]
