Apple BASIC

Apple 1 basic was on cassette tape and took about 30 seconds to load.

Some of the following was in the BASIC:

• variables, numeric simple variable, A,N, A1, T6
  
• Numeric array variable, N, T, B1, T4
  
• character string variable, letter+$, A$,N$

Functions

• ABS(X), SGN(x), Peek(x), Rnd(x), Len(var$).
  
• Arrays, A(15), D(100). Used the Dim statement ot declare.
  
• Strings= Print "this is a string", used the quotes.
  
• Substrings, A$="ABCDEFG"
  
• Print A$ = ABCDEFG
  
• Print A$(5) = EFG
  
• Print A$(2,6)= BCDEF

Commands

• Auto val1, val2==== Starts automatically supplying line numbers.
  
• val1= first line number value.
  
• Val2= increment between line numbers valuse.
  
• Clr== sets all variables to zero.
  
• Del val1, val2, erases from the program all lines numbered from val1 to val2. if just val1 is used, one line is deleted.
  
• List val1,val2, displays all program statements on lines numbered from val1to val2. If you use just list the whole program is listed.
  
• RUN val1 - does a CLR then initiates program execution beginning at line val1. if val1 is omitted, program starts at lowest number.
  
• SCR == Deletes the entire program, nothing is saved.
  
• HIMEM =(expr) sets the high memory boundary for user programs, in decimal. Initializes to 4096.
  
• LOMEM=(expr) sets the low memory boundary for user programs,in deciaml. Initializes to 2048.

Statements:

• LET
  
• INPUT
  
• PRINT
  
• TAB(EXPR)
  
• FOR
  
• NEXT
  
• IF(EXPR) THEN
  
• GOTO
  
• GOSUB,
  
• RETURN
  
• DIM
  
• REM
  
• END
  
• POKE EXPR1
  
• EXPR2
  
• CALL

In Apple Basic you could input more than one statement on a line. Each statement must be separated by a colon (:).

Error messages

• SYNTAX
  
• >32767 ERR
  
• >255 ERR, A VALUE RESTRICTED TO THE RANGE 0 TO 255 WAS OUTSIDE THAT RANGE.
  
• BAD BRANCH ERR
  
• BAD RETURN ERR
  
• BAD NEXT ERR
  
• >8 GOSUBS ERR Results from more than 8 nested GOSUBS.
  
• >8 FORS ERR Results from more than 8 nested FOR loops.
  
• END ERR Last statement was not an END.
  
• MEM FULL ERR
  
• TOO LONG ERR Results from too many nested parentheses.
  
• DIM ERR
  
• RANGE ERR An array or string subscript was larger than the Dimensioned value or smaller that 1.
  
• STR OVFL ERR The number of characters assigned to a string exceeded the dimensioned value for that string.
  
• STRING ERR Results from an attempt to execute an illegal string operation.
  
• RETYPE LINE Results from illegal data being typed in response to an INPUT statement.