Applesoft BASIC was a dialect of Microsoft BASIC supplied with the Apple II series of computers.

As Steve Wozniak, the creator of Integer BASIC and the only person who understood it well enough to add floating point features, was busy with the Disk II drive and controller and with Apple DOS, Apple turned to Microsoft, who was the BASIC vendor of choice after their success with Altair BASIC, and licensed a 10 KB assembly language version of BASIC dubbed " Applesoft.

" Apple reportedly obtained an eight-year license for Applesoft BASIC from Microsoft for a flat fee of $ 21, 000, renewing it in 1985 through an arrangement that gave Microsoft the rights and source code for Apple's Macintosh version of BASIC.

Applesoft was similar to ( and indeed had a common code base with ) Microsoft BASIC implementations on other 6502-based computers, such as Commodore BASIC: it used line numbers, and spaces were not necessary in lines.

While Applesoft was slower than Integer BASIC, it had many features that the older BASIC lacked:

Conversely, Applesoft lacked the ( remainder ) operator that had been present in Integer BASIC.

Whereas Wozniak originally referred to his Integer BASIC as " Game BASIC ," having written it so he could write a Breakout clone for his new computer, few action games were written in Applesoft BASIC for several reasons:

Hello World in Applesoft BASIC could be entered as the following:

The can be used in Applesoft BASIC as a shortcut for " PRINT ", though spelling out the word is not only acceptable but canonical — Applesoft converted "?

Donn Denman ported Applesoft BASIC to SOS and reworked it to take advantage of the extended memory of the Apple ///.

* Despite its heritage, Applesoft lacked commands common to most other Microsoft BASIC interpreters, such as INSTR ( which searched for a substring in a given string ; this had to be done manually with loops and the MID $ function ), PRINT USING ( which formatted numbers with commas and currency signs according to a format string ), and INKEY $ ( which checked for a keypress without stopping the program as Applesoft's GET command — analogous to the INPUT $ function — did, although a PEEK location did provide this functionality ).

* There was a well-documented bug in Applesoft BASIC that could actually crash the interpreter if ONERR GOTO was in effect and numerous program errors occurred.

* Both Integer BASIC and Applesoft used tokenizing to reduce the memory requirements of programs and to speed their interpretation.

Integer BASIC used characters with codes above 127 for normal text and codes below 128 for tokens ; Applesoft used exactly the reverse.

The first version of Applesoft was released in 1977 only on cassette tape and lacked proper support for high-resolution graphics.

Applesoft II, which was made available on cassette and disk and in the ROM of the Apple II Plus and subsequent models, was released in 1978.

Applesoft converted integer numbers to real before performing operations on them, converting the result back to an integer only if it was to be assigned to a ( 16-bit signed ) integer variable.

* The program was stored as a linked list of lines ; a or took O ( n ) ( linear ) time, and although Applesoft programs were not very long compared to today's software, on a 1 MHz 6502 this could be a significant bottleneck.

Microsoft's CLS command ( for clearing the screen ) was renamed HOME in Applesoft.

Later it was discovered by an enterprising hacker that the required code was actually in the Applesoft ROM ( though it was never executed ) and could be called there instead: CALL-3288 or ( equivalent ) 62248.

His experiences testing Applesoft BASIC inspired him to design a competing product, called Notzo BASIC, which was never implemented.

The original Math Blaster was written in Applesoft Basic and the Microsoft equivalent.

Apple Computer licensed a more full-featured ( but also much slower ) BASIC from Microsoft soon after the Apple II was released in 1977, introduced some tweaks, named it Applesoft BASIC, and included the second version of it in the ROMs of the Apple II Plus, which was released in.

Applesoft BASIC was included in the ROMs of all Apple II models from the Apple II Plus forward, and eventually became the platform for far more programs than Integer BASIC.

When running Apple DOS, it was possible ( at the expense of clearing the current BASIC program from memory ) to switch between Applesoft BASIC and Integer BASIC by typing either INT ( to enter Integer BASIC ) or FP ( to enter Applesoft BASIC )— provided, of course, that the requested language was either in ROM or loaded into RAM.

It is this latter version, which has some syntax differences from the first as well as support for the Apple II high-resolution graphics modes, that most people mean by the term " Applesoft.

* Applesoft could be extended by two means: the ampersand (&) command and the USR () function.

Unlike Integer BASIC, Applesoft did not tokenize literal numbers appearing in the code but stored them digit by digit.

The ROM revision for a specific Apple IIc is determined by entering the Applesoft BASIC programming language and typing in the command PRINT PEEK ( 64447 ) which returns the value indicating the particular ROM version.

From there, the graphic could be referenced by number ( a table could contain up to 255 shapes ), and built-in Applesoft routines permitted scaling, rotating, and drawing or erasing the shape.

However, the Apple II's Integer BASIC ROMs were replaced by Applesoft BASIC ROMs since the Apple II +, and the latter didn't contain the SWEET16 interpreter code.

The core was based on 6502 Microsoft BASIC, and as such it shares most of the core code with other 6502 BASICs of the time, such as Applesoft BASIC.

VTech owed much of this compatibility to the fact that they were able to license Applesoft BASIC ( which constitutes the largest and most complex part of an Apple II's ROM contents ) from Microsoft just as Apple did, heavily reducing the amount of code that had to be reimplemented.

* Like Applesoft BASIC, Lua has a floating-point type as its sole numeric type when configured for desktop computers, and it has no bitwise operators either.

Applesoft BASIC was a favorite tool as it was widely available and allowed easy machine-level access through its PEEK and POKE statements.

One key feature of the MPF II was its Chinese BASIC, a version of Chinese-localized BASIC based on Applesoft BASIC.

One key feature of the MPF III in some models was its Chinese BASIC, a version of Chinese-localized BASIC based on Applesoft BASIC.

It cited the presence of some of the same embedded strings, such as the name " James Huston " ( an Apple programmer ), and " Applesoft ," on both the Apple and Franklin system disks.

The length of an Applesoft BASIC variable name is restricted to two bytes.

( A popular speed optimizing technique in most interpreted BASICs — including Applesoft — is to put all frequently used constants into variables, because fetching the variable's value is faster than converting a number from text — a difference which becomes significant, given perhaps hundreds of iterations.

The Applesoft BASIC Reference Manual includes a section entitled " Rounding can be Curious ", in which it is documented that the ROUND function, which rounds a number to a prescribed accuracy, is not monotonic: in other words, for some x and y, such that x < y, ROUND ( x )> ROUND ( y ).