Cheesecake BASIC v0 Readme

 

CONTENTS:

 

INTRODUCTION 

Cheesecake BASIC is an implementation of a simple BASIC interpreter. 
It was originaly written in QuickBasic.

Following is a description of the files included in the Cheesecake BASIC distribution:

ccbasic.bi Global include file
ccbasic.bas Cheesecake BASIC main module, symbol table, memory and other functions
interp.bas Interpreter and Lexer
parser.bas Parser functions
parser1.bas More parser functions
ccbasic.mak MAK file for QuickBasic to compile the program

(Note: The Powerbasic version of Cheesecake BASIC has only one source file: ccbasic.bas)
ccbasic.exe Cheesecake BASIC executable
readme.txt Documentation
samples\hangman.bas A sample file implementing a "Hangman" game
samples\words.txt Input file used by hangman.bas

DATA TYPES

Cheesecake BASIC supports the following data types:

  • 2-byte integers (%)

  • 4-byte reals (!)

  • strings ($)

Symbols without a suffix type character (%, !, $) are integer whatever their name.

INTERPRETER COMMANDS

The Cheesecake BASIC interpreter has the following commands:

BYE Exits the interpreter
DUMP [SYM|MEM|SYS] [TO "FileName"]  Dumps interpreter structures
LIST [Line [- Line] ] Lists program
LOAD "FileName" Loads a program
NEW Resets the interpreter
RENUM [Increment] Renumbers program lines
RUN Runs program
SAVE "FileName"  Saves program
TRACE {ON | OFF} Turns program trace on/off
BRK Line Sets breakpoint at specific line
CBRK [Line] Clears breakpoint. If no line is specified, clears all breakpoints in program
CONT  Continues execution after a STOP in the program or a breakpoint hit
Line [Basic statements] Adds/Removes/Replaces a program line

Cheesecake BASIC LANGUAGE


Line numbers are required in Cheesecake BASIC.


Multiple statements are allowed in one line, separated by colons e.g.
        10 PRINT "Hello" : GOSUB 300 : END

SUPPORTED BASIC COMMANDS

Cheesecake BASIC implements the following BASIC instructions:

  • BEEP

  • CHDIR "directory"

  • CLOSE #filenumber

  • CLS

  • COLOR fg [, bg]

  • DATA constant [,constant]*

  • DEF functionname(args) = expression
            Note that FN is not required e.g.:
            10 DEF PlusOne(x) = x + 1
            20 PRINT PlusOne(5)

  • DIM var [, var]*
            Note that arrays are limited to 3 dimensions

  • END

  • ERROR errornumber

  • FIELD #filenumber, integer as fieldname [, integer as fieldname]*

  • FOR id = integer TO integer [STEP integer]

  • GET #filenumber

  • GOSUB linenumber

  • GOTO linenumber

  • IF exp THEN statements [ ELSE statements ]

  • INPUT [#filenumber,] [prompt{,|;}] var [, var]*

  • KEY (keynumber) { ON | OFF }

  • [LET | LSET | RSET] var = exp

  • LINE INPUT [#exp,] [prompt {,|;}] var

  • LOCATE x, y

  • NEXT [id]

  • ON ERROR GOTO linenumber

  • ON exp GOSUB linenumber [, linenumber]*

  • ON exp GOTO linenumber [, linenumber]*

  • ON KEY (keynumber) GOSUB linenumber

  • ON TIMER (seconds) GOSUB linenumber

  • OPEN filename [FOR {INPUT|OUTPUT|APPEND|RANDOM}] as #filenumber [LEN=len]

  • PRINT [#filenumber,] print-list

  • PUT #filenumber

  • RANDOMIZE [exp]

  • READ var [,var]*

  • REM (or apostrophe)

  • RESTORE [linenumber]

  • RESUME [ NEXT | linenumber]

  • RETURN [linenumber]

  • SEEK #filenumber, recordnumber

  • SHELL command

  • SLEEP seconds

  • TIMER { ON | OFF }

  • WEND

  • WHILE exp

  • STOP

SUPPORTED FUNCTIONS

Cheesecake BASIC implements the following functions:

  • ABS 

  • ASC 

  • ATN 

  • CHR$ 

  • CINT 

  • COS 

  • CURSORX 

  • CURSORY 

  • CVI 

  • CVS 

  • DATE$ 

  • EOF 

  • ERL 

  • ERR 

  • ERT$ (returns error text) 

  • EXP 

  • FIX 

  • INKEY$ 

  • INSTR 

  • INT 

  • LCASE$ 

  • LEFT$ 

  • LEN 

  • LOC 

  • LOF 

  • LOG 

  • LTRIM$ 

  • MID$ 

  • MKI$ 

  • MKS$ 

  • RIGHT$ 

  • RND 

  • RTRIM$ 

  • SEEK 

  • SIN 

  • SQR 

  • STR$ 

  • TIME$ 

  • TIMER 

  • UCASE$ 

  • VAL

LIMITATIONS

Cheesecake BASIC has a (big) number of limitations. 

The file ccbasic.bi contains constants for all (or most) of the limits in Cheesecake BASIC.

Among the limitations are:

  • Number of dimensions in an array (3).

  • Number of integer, real and string variables (or array elements). In the QuickBasic implementation of Cheesecake BASIC this number is 500 of each.

  • Number of program lines. In the QuickBasic implementation of Cheesecake BASIC this is limited to 500.

  • Number of parameters in user-defined functions. In the QuickBasic implementation of Cheesecake BASIC this number is 3.

  • Maximum loop nesting: 5 levels

  • Maximum subroutine levels: 10

  • Etc.

FEEDBACK

Comments, bug reports etc. can be sent to the author at noktosoft@megafolio.com

UPDATES

The latest version of the interpreter can be downloaded from noktosoft.megafolio.com

LEGAL

This is free software subject to the GNU General Public License as described in the source code