CBASIC in General CBASIC2 Compile-Time Toggled Options XREF Cross Reference Facility Compiler Error Messages Run-Time Error Messages -- Warnings Run-Time Error Messages -- Error Codes CBASIC2 Reserved Words CBASIC2 Expression Hierarchy CBASIC2 Predefined Functions :CBASIC2: CBASIC in General CBASIC is a compiler BASIC which may be executed on any floppy disk based CP/M system having at least 20K bytes of memory. In order to make the best use of the power and flexibility of CBASIC, a dual floppy disk system and at least 32K of memory is recommended. If CBASIC is executed in a system smaller than 20K, a CP/M LOAD ERROR may occur. The CBASIC system consists of two programs -- CBASIC and CRUN. CBASIC is the compiler, and CRUN is the run-time intepreter. In a typical CBASIC session, the user will write the program using ED, compile it using CBASIC (with the $B option to suppress listing), and run it using CRUN. Refer to the 84-page CBASIC manual -- C B A S I C A Commercially Oriented Compiler/Interpreter BASIC Language Facility for CP/M Systems February 17, 1978 CBASIC2 is an upward-compatable (in terms of source code) extension of the original CBASIC. In addition to all of the features of the original CBASIC, CBASIC2 adds the following: 1. Integer variables 2. Chaining with common variables 3. Additional pre-defined functions 4. Cross Reference capability Note that CBASIC2 is upward-compatable with CBASIC only in terms of the source code files. An INT file created under CBASIC will not execute with the Version 2 Run-Time Monitor (CRUN2). For further information, refer to the 100-page reference manual -- C B A S I C A Commercially Oriented Compiler/Interpreter BASIC Language Facility for CP/M Systems Version 2 May 1, 1979 :CBASIC2: CBASIC2 Compile-Time Toggled Options Compiler toggles are a series of switches that can be set when the compiler is executed. The toggles are set by typing a dollar-sign ($) followed by the letter designations of the desired toggles starting one space or more after the program name on the command line. Toggles may only be set for the compiler. Examples of compiler toggles and invocation forms are -- CBAS2 INVENTRY $BGF B:CBAS2 A:COMPARE $GEC CBAS2 PAYROLL $B CBAS2 B:VALIDATE $E CBASIC Compiler Toggles TOGGLE B: Suppresses the listing of the program on the console during compilation. If an error is detected, the source line with the error and the error message will be printed even if Toggle B is set. Toggle B does not affect listing to the printer (Toggle F) or disk file (Toggle G). Toggle B is initially off. TOGGLE C: Suppresses the generation of an INT file. Engaging this toggle will provide a syntax check without the overhead of writing the intermediate file. Toggle C is initially off. TOGGLE D: Suppresses translation of lower-case letters to upper-case. For example, if Toggle D is on, 'AMT' will not refer to the same variable as 'amt'. Toggle D is initially off. TOGGLE E: Causes the run-time program (CRUN2) to accompany any error messages with the CBASIC line number in which the error occurred. Toggle E must be set in order for the TRACE option (see section 13.4 of the manual) to work. Toggle E is initially off. TOGGLE F: Causes the compiler output listing to be printed on the LST: device in addition to the system console. Toggle F is initially off. TOGGLE G: Causes the compiler output listing to be written to diskette. The file containing the compiler listing has the same name as the .BAS file, but its type is .LST. Normally the disk listing will be placed on the same source drive as the source file. The operator may select another drive by specifying the desired drive, enclosed in parens, following the G toggle; for example, CBAS2 B:TAX $G(A:) extracts the source from drive B: and sends the listing to drive A:. Toggle G is initially off. :CBASIC2: XREF Cross Reference Facility The XREF.COM Cross Reference utility program produces a file which contains an alphabetized list of all identifiers used in a CBASIC program. The usage of the identifier (function, parameter, or global) is provided, as well as a list of each line in which that identifier is used. The file created has the same name as the CBASIC source file and is of type XRF. The standard output is 132 columns wide. The following command is used to invoke XREF -- XREF [disk ref] [$] ['title'] If the disk reference is specified, it instructs XREF as to what disk to place the output on. The toggles are described on the next display. The optional title field must be the last field in the command line. All characters following the first apostrophe on the command line up to the second apostrophe or until the end of the command line become the title. The title is truncated to 30 characters if the listing is 132 columns wide and 20 characters if the D toggle (80 column listing) is specified. XREF Toggles Toggle A: Causes the listing to be otput to the list device as well as the disk file. Toggle B: Suppresses output to the disk. If only the B toggle is specified, no output is produced. Toggle C: Suppresses output to the disk and permits output to the list device; same as A and B combined. Toggle D: Causes output to be 80 columns wide instead of 132. Toggle E: Produces output with only the identifiers and their usage. For example, the following command produces a cross reference listing on the list device which is 80 columns wide -- XREF PROG $CD :CBASIC: Compiler Error Messages Text Messages NO SOURCE FILE: .BAS The compiler could not locate a source file used in either a CBASIC command or an INCLUDE directive. PROGRAM CONTAINS n UNMATCHED FOR STATEMENT(S) There are n FOR statements for which a NEXT could not be found. PROGRAM CONTAINS n UNMATCHED WHILE STATEMENT(S) There are n WHILE statements for which a WEND could not be found. WARNING: INVALID CHARACTER IGNORED The previous line contains an invalid ASCII character; this character is ignored by the compiler, and a question mark is printed in its place. OUT OF DISK SPACE The compiler has run out of disk space while attempting to write either the INT or LST files. Text Messages (Con't) OUT OF DIRECTORY SPACE The compiler has run out of directory entries while attempting to create or extend a file. DISK ERROR A disk error occurred while trying to read or write to a disk file. INCLUDE NESTING TOO DEEP NEAR LINE n An include statement near line n in the source program exceeds the maximum level of nesting of source files. 2-Letter Error Codes BF -- Branch into Function A branch into a multiple line function from outside was attempted. BN -- Bad Number An invalid numeric constant was encountered. CE -- Close Error The intermediate (.INT) file could not be closed. CI -- Close Include An invalid file name in an %INCLUDE statement. CS -- COMMON Statement error A COMMON statement which was not the first statement in the program was detected. CV -- COMMON Variable error An improper reference to a subscripte variable in a COMMON statement. DE -- Disk Error A disk error occurred while trying to read the .BAS file. DF -- Disk Full There was no space on the disk or the disk directory was full. The .INT file was not created. DL -- Duplicate Line number The same line number was used on two different lines. Other compiler errors may cause a DL error message to be printed even if duplicate line numbers do not exist. DP -- Defined Previously A variable in a DIM statement was previously defined. EF -- Exponential Format A number in exponential format was input with no digits following the E. FA -- Function Attribute A function name appears on the left side of an assignment statement but is not within that function. FD -- Function Definition A function name that has been previously defined is being redefined in a DEF statement. FE -- FOR Error A mixed mode expression exists in a FOR statement which the compiler cannot correct. FI -- FOR Index An expression which is not an unsubscripted numeric variable is being used as a FOR loop index. FN -- Function parameter Number A function reference contains an incorrect number of parameters. FP -- Function Parameter type A function reference parameter type does not match the parameter type used in the function's DEF statement. FU -- Function Undefined A function has been referenced before it has been defined. IE -- IF Expression An expression used immediately following an IF evaluates to type string. Only type numeric is permitted. IF -- In File A variable used in a FILE statement is of type numeric where type string is required. IP -- Input Prompt An input prompt string is not surrounded by quotes. IS -- Invalid Subscript A subscripted variable was referenced before it was dimensioned. IT -- Invalid Toggle An invalid compiler directive was encountered. IU -- Invalid Use A variable defined as an array is used with no subscripts. MF -- Mixed Format An expression evaluates to type string when type numeric is required. MM -- Mixed Mode Variables of type string and type numeric are combined in the same expression. MS -- Mixed String A numeric expression was used where a string expression is required. ND -- No DEFFN A FEND statement was encountered without a corresponding DEF. NI -- NEXT Index A variable referenced by a NEXT statement does not match the variable referenced by the associated FOR statement. NU -- NEXT Unexpected A NEXT statement occurs without an associated FOR statement. OF -- Out of Function A branch out of a multiple line function from inside the function was attempted. OO -- ON Overflow More than 25 ON statements were used in the program. PM -- ?? A DEF statement appeared within a multiple line function. Functions may not be nested. SE -- Syntax Error The source line contains a syntax error. SF -- SAVEMEM File A SAVEMEM statement uses an expression of type numeric to specify the file to be loaded. This expression must be a string. Possibly the quotation marks were left off a string constant. SN -- Subscript Number A subscripted variable contains an incorrect number of subscripts. SO -- Syntax Overflow The expression is too complex and should be simplified and placed on more than one line. TO -- Table Overflow The program is too large for the system. The program must be simplified or the system size increased. UL -- Undefined Line number A line number that does not exist has been referenced. US -- Undefined String A string has been terminated by a carriage return rather than quotes. VO -- Variable Overflow Variable names are too long for one statement. This should not occur. WE -- WHILE Error The expression immediately following a WHILE statement is not numeric. WU -- WHILE Undefined A WEND statement occurs without an associated WHILE statement. :CBASIC: Run-Time Error Messages -- Warnings Two textual run-time error messages are presented by CRUN: NO INTERMEDIATE FILE A file name was not specified with the CRUN command, or no file of type .INT and the specified file name was found on disk. IMPROPER INPUT - REENTER This message occurs when the fields entered from the console do not match the field specified in the INPUT statement. This can occur when field types do not match or the number of fields entered is different from the number of fields specified. All fields specified by the INPUT statement must be reentered. 2-Letter Warning Codes DZ -- Divide by Zero A number was divided by zero. The result is set to the largest valid CBASIC number. FL -- Field Length A field length greater than 255 bytes was encountered during a READ LINE. Only the first 255 characters of the record are retained. LN -- Logarithm error The argument given in the LOG function was zero or negative. The value of the argument is returned. NE -- NEgative number A negative number was specified following the raise to a power operator (^). The absolute value is used in the calculation. OF -- OverFlow A calculation produced a number too large. The result is set ot the largest valid CBASIC number. SQ -- SQuare root error A negative number was specified in the SQR function. The absolute value is used. :CBASIC: Run-Time Error Messages -- Error Codes AC -- AsCii error The string used as the argument in an ASC function evaluated to a null string. BN -- BUFF Number The value following the BUFF option in an OPEN or CREATE statement is less than 1 or greater than 52. CC -- Chain Code A chained program's code area is larger than the main program's code area. CD -- Chain Data A chained program's data area is larger than the main program's data area. CE -- Close Error An error occurred upon closing a file. CF -- Chain Function A chained program's constant area is larger than the main program's constant area. CP -- Chain Var Storage A chained program's variable storage area is larger than the main program's variable storage area. CS -- Chain SAVEMEM A chained progra reserved a difference amount of memory with a SAVEMEM statement than the main program. CU -- Close Undefined file A close statement specified a file number that was not active. DF -- Defined File An OPEN or CREATE was specified with a file number that was already active. DU -- Delete Undefined file A DELETE statement specified a file number that was not active. DW -- Disk Write error An error occurred while writing to a file. This occurs when either the directory or the disk is full. EF -- End of File A read past the end of file occurred on a file for which no IF END statement has been executed. ER -- Error in Record An attempt was made to write a record of length greater than the maximum record size specified in the associated OPEN, CREATE, or FILE statement. FR -- File Rename An attempt was made to rename a file to an existing file name. FT -- File Toggle A FILE statement was executed when 20 files were already active. FU -- File Undefined An attempt was made to read or write to a file that was not active. IF -- Invalid File name A file name was invalid. IR -- Invalid Record number A record number less than one was specified. IV -- Invalid Version An attempt was made to execute an INT file created by a Version 1 Compiler. IX -- ?? A FEND statement was encountered prior to executing a RETURN statement. LW -- Line Width A line width less than 1 or greater than 133 was specified in an LPRINTER WIDTH statement. ME -- MAKE Error An error occurred while creating or extending a file because the disk directory was full. MP -- MATCH Parameter The third parameter in a MATCH function was zero or negative. NF -- Number of FILE The file number specified was less than 1 or greater than 20. NM -- No Memory There was insufficient memory to load the program. NN -- No Number field An attempt was made to print a number with a PRINT USING statement but there was not a numeric data field in the USING string. NS -- No String field An attempt was made to print a string with a PRINT USING statement but there was not a string field in the USING string. OD -- Overflow Data A READ statement was executed with no DATA available. OE -- OPEN Error An attempt was made to OPEN a file that didn't exist and for which no IF END statement had been previously executed. OI -- ON Index The expression specified in an ON ... GOSUB or an ON ... GOTO statement evaluated to a number less than 1 or greater than the number of line numbers contained in the statement. OM -- Overflow Memory The program ran out of memory during execution. QE -- Quote Error An attempt was made to PRINT to a file a string containing a quotation mark. RB -- Random BUFF Random access was attempted to a file activated with the BUFF option specifying more than 1 buffer. RE -- READ Error An attempt was made to read past the end of a record in a fixed file. RG -- RETURN with no GOSUB A RETURN occurred for which there was no GOSUB. RU -- Random Undefined A random read or print was attempted to other than a fixed file. SB -- SuBscript An array subscript was used which exceeded the boundaries for which the array was defined. SL -- String Length A concatenation operation resulted in a string of more than 255 bytes. SO -- SAVEMEM The file specified in a SAVEMEM statement could not be located on the referenced disk. SS -- SubString error The second parameter of a MID$ function was zero or negative. TF -- Too many Files An attempt was made to have more than 20 active files simultaneously. TL -- TAB Length A TAB statement contained a parameter less than 1 or greater than the current line width. UN -- UNdefined edit string A PRINT USING statement was executed with a null edit string. WR -- WRite error An attempt was made to write to a file after it had been read, but before it had been read to the end of the file. :CBASIC: CBASIC Reserved Words ABS AND AS ASC ATN BUFF CALL CHAIN CHR$ CLOSE COMMAND$ COMMON CONCHAR% CONSOLE CONSTAT% COS CREATE DATA DEF DELETE DIM ELSE END EQ EXP FEND FILE FOR FRE GE GO GOSUB GOTO GT IF INITIALIZE INP INPUT INT INT% LE LEFT$ LEN LET LINE LOG LPRINTER LT MATCH MID$ NE NEXT NOT ON OPEN OR OUT PEEK POKE POS PRINT RANDOMIZE READ RECL RECS REM REMARK RENAME RESTORE RETURN RIGHT$ RND SADD SGN SIN SIZE SQR STEP STOP STR$ SUB TAB TAN THEN TO UCASE$ USING VAL WEND WHILE WIDTH XOR :CBASIC2: Expression Hierarchy The Hierarchy for expression evaluation is a follows -- 1. nested parentheses () 2. power operator ^ 3. * / 4. + - concatenation[+] unary[+ -] 5. relational operators: < <= > >= = <> LT LE GT GE EQ NE 6. NOT 7. AND 8. OR XOR :CBASIC2: Predefined Functions I/O Functions CONSTAT% - Returns the console status as an integer. If ready, a logical TRUE is returned. CONCHAR% - Reads one character from the console device. Machine-Language Functions PEEK () - Returns the contents of the memory location given by the expression. POKE , - Low-order eight bits of second expression are stored in memory location selected by first expression. CALL - CALL a machine language program at address specified. SAVEMEM , - Reserve number of bytes and load the file specified by the string into the reserved area. Numeric Functions FRE ABS(x) INT(x) INT%(x) FLOAT(i%) RND SGN(x) ATN(x) COS(x) EXP(x) LOG(x) [e] SIN(x) SQR(x) TAN(x) String Functions ASC(a$) CHR$(i%) LEFT$(a$,i%) LEN(a$) UCASE$(a$) MATCH(a$,b$,i%) MID$(a$,i%,j%) RIGHT$(a$,i%) STR$(x) VAL(a$) COMMAND$ SADD(a$) Disk Functions RENAME(a$,b$) SIZE(a$) User-Defined Functions The general forms are -- [] DEF [] = and [] DEF [] . . . [] FEND