Notes:

9 The access mode defines the direction of I/O transfers.

0 Because OS-9 files are byte-addressed and are unformatted, you can set up the filing system you want for a particular application. Your system can read the data contained

0 You can expand a file using PRINT, WRITE, or PUT statements to write beyond the current end-of-file.

Examples:

OPEN #TRANS,"transportation":UPDATE

OPEN #SPOOL,"/user4/report":WRITE

OPEN #OUTPATH,name$:UPDATE+EXEC

Sample Program:

PROCEDURE readerr ODIM A:STRINGL801 ODIM PATH:HYTE EOPEN #PATH,"/D0/SYS/ERRMSG":READ OWHILE EOFC#PATH)<>TRUE DO DREAD #PATH,A SPRINT A EENDWHILE OCLOSE #PATH REND

PRINT A$="YES" or B$="YES"

BASIC09 Command Reference / 11

PROCEDURE uppercase ODIM PHRASE,NEWSTRING:STRINGL807; CHARACTER: STRINGL1J; T,X:INTEGER ONEWSTRING="" PHRASE="" OPRINT "Type a phrase in lowercase and I will make it uppercase." OINPUT PHRASE OFOR T=1 TO LENCPHRASE) OCHARACTER=MID$CPHRASE,T,1) OX=ASCCCHARACTER) DIF X<97 OR X>122 THEN ONEWSTRING=NEWSTRING+CHARACTER OELSE OX=X-32 ONEWSTRING=NEWSTRING+CHR$CX) REND I F ONEXT T OPHRASE=NEWSTRING ONEWSTRING="" OPRINT PHRASE REND

PARAMEstablishes variables to receive from another procedure

Syntax: PARAM variable[,...] [: type] [; variable] [,... ] [: type] [...]

Function: Defines the parameters that a called procedure expects to receive from the procedure that calls it. When using PARAM, be sure that the total size of each parameter in the calling procedure's RUN statement is the same as the defined size in the called procedure's PARAM statement.

· BASIC09 checks the size of each parameter to prevent accidental access to storage other than that assigned to the parameter. However, BASIC09 does not check that parameters are of the proper type. In most cases you must be sure that types evaluated in RUN statements match the types defined in the PARAM statements.

However, because BASIC09 does not perform type checking, it is possible to perform useful but normally illegal type conversions of identically-sized data structures. For example, you could pass a string of 80 characters to a procedure expecting a byte array of 80 elements. Each character in the string is assigned a corresponding position in the array.

· You declare simple arrays by using the variable name, without a subscript, in a PARAM statement.

11-108

You can declare several variables of the same type by separating them with commas. To separate variables of different types, follow each type group with a colon, the type name, and then a semicolon.

If you do not include a maximum length for a string variable enclosed in brackets following the type, like this:

DIM name:string[251

BASIC09 uses a default length of 32 characters for strings. You can declare shorter or longer lengths, to the capacity of BASIC09's memory.

0 Arrays can have one, two, or three dimensions. The PARAM format for dimensioned arrays is the same as for simple variables except you must follow each array name with a subscript, enclosed in parentheses, to indicate its size. The maximum array size is 32767.

Arrays can be either of the standard BASIC09 type, or of a user-defined type. To create your own data types for simple variables, arrays, and complex data structures, see TYPE.

The first procedure asks you to enter a decimal number. Then, it asks you to choose whether you want to convert the number to binary or hexadecimal. Depending on your choice, the procedure calls (using RUN) either a procedure named Binary or a procedure named Hex. It passes the number you typed to the appropriate procedure for conversion.

REND

" in hexadecimal."

PAUSE The array is now full.

MEMVAL = PEEKC4450)

This procedure asks you to type a phrase in uppercase characters. It then uses ADDR to locate the area in memory where BASIC09 stores the phrase. Next, it reads each character from memory with PEEK, converts it to lowercase if necessary, and pokes the new value back into the same location. When the procedure displays the contents of the phrase, it is all lowercase.

PROCEDURE lowercase ODIM LOC,T:INTEGER; PHRASE:STRINGI80J OPRINT "Type a phrase in UPPERCASE and I'll make it lowercase." OINPUT PHRASE OLOC=ADDRCPHRASE) OFOR T=LOC TO LOC+LENCPHRASE) OX=PEEKCT) OIF X>32 AND X<91 THEN OX=X+32 OPOKE T, X REND I F ONEXT T OPRINT PHRASE REND

BASIC09 Command Reference / 11

11-115

BASIC09 Reference

POKE Stores a value in a memory location

Syntax: POKE mem, value

Function: Stores a value at the specified memory address, relative to the current process's address space. Mem is an absolute address at which BASIC09 stores a byte type value. POKE is the complement of the PEEK statement.

You should use care when using POKE. Because it changes the value in memory, a POKE to the wrong portion of memory could cause OS-9, BASIC09, or your procedures to malfunction until you reboot the system.

See also ADDR.

Parameters:
mem An integer value representing the location of
the memory byte you want to change.
value The value to store in the specified memory
location.
Examples:

POKE 1 5250 , 1 3

11-116

BASIC09 Command Reference / 11

Sample Program:

This procedure asks you to type a phrase in uppercase characters. It then uses ADDR to locate the area in memory where BASIC09 stores the phrase. Next, it reads each character from memory, converts it to lowercase if necessary, and uses POKE to store the new value back in the same location. When the procedure next displays the contents of the phrase, it is all lowercase.

PROCEDURE lowercase ODIM LOC,T:INTEGER; PHRASE:STRINGL80J OPRINT "Type a phrase in UPPERCASE and I'll make it lowercase." DINPUT PHRASE OLOC=ADDRCPHRASE) OFOR T=LOC TO LOC+LENCPHRASE) OX=PEEKCT) OIF X32 AND X<91 THEN OX=X+32 OPOKE T, X OENDI F ONE XT T OPRINT PHRASE REND

11-117
BASIC09 Reference

POS Returns cursor's column position

Syntax: POS

Function: Returns the current column position of the cursor. Parameters: None Examples:

PRINT POS

Sample Program:

This procedure is a simple typing program that uses POS to make sure that words are not split when you type to the end of the screen. After you type 25 characters on a line, the procedure breaks the line at the next space character.

PROCEDURE wordwrap
ODIM CHARACTER:STRINGf1J
OPRINT USING "S32^"; "Word Wrap Program"
OPRINT USING "S32^"; "Press LCTRLILCl to Exit"
OPRINT
OSHELL "TMODE -ECHO"
OWHILE CHARACTER<>" " DO
OGET *1 ,CHARACTER
OPRINT CHARACTER;
OIF POS>25 AND CHARACTER=" " THEN
OPRINT CHR$C13)
REND I F
OENDWHILE
OSHELL "TMODE ECHO"
REND

11-118

BASIC09 Command Reference l 11

PRINT Displays text

Syntax: PRINT [#path] [TAB(pos);] data[;data...]

Function: Prints numeric or string data on the video display unless another path is specified.

Parameters:

path The number corresponding to an opened device
or file. If you do not specify path, the default
is # 1, the video screen (standard output
device). To print to another device or file, first
OPEN a path to that file or device (see
OPEN).
pos A column number that tells TAB where to
begin printing. Specify any number from 0 to
the width of your video display.
data Any numeric or string constant or variable.
Enclose string constants within quotation
marks. All data items must be separated by a
semicolon or comma.
Notes:

· If you specify more than one data item in the statement, separate them with commas or semicolons.

· If you use commas, PRINT automatically advances to the next tab zone before printing the next item. In BASIC09, tab zones are 16 characters apart.

· If you use semicolons or spaces to separate data items, BASIC09 prints the items without any spaces between them. BASIC09 begins the next print item immediately following the end of the last print item.

· If you end a print item without any trailing punctuation, PRINT begins printing at the beginning of the next line.

11-119

BASIC09 Reference

If the data being printed is longer than the display screen width, PRINT moves to the next line and continues printing the data.

TAB causes BASIC09 to begin displaying the specified data at the column position specified by TAB. If the output line is already past the specified TAB position, PRINT ignores TAB.

You can concatenate items for printing using the plus (+ symbol, for example: print "hello "+name$+" +lastname$.

PRINT displays REAL numbers with nine or fewer digits in regular format. It displays REAL numbers with more than nine digits in exponential format. For example, 1073741824 is displayed as 1 . 0 7 3 7 41 8 2 E + 0 9.

You must enclose string constants within quotation marks.

Examples:

PRINT A$

PRINT "Menu Items"

PRINT COUNT

PRINT VALUE,TEMP+Cn/2.5),LOCATION$
PRINT #PRINTER-PATH,"The result i5 ";NUMBER
PRINT #OUTPATH FMT$,COUNT,VALUE

PRINT "what

i5"+NAME$+`5 age? ";

PRINT "INDEX:

";I;TAHC25);"VALUE

";VALUE

11-120

BASIC09 Command Reference / 11

Sample Program:

This procedure asks you to type a word or phrase, then displays it backwards by reading each character from end to beginning and using PRINT to display it on the screen.

PROCEDURE reverse ODIM PHRASE,TITLE:STRING; T,HEGIN:INTEGER ODIM INSTRUCTIONS:STRINGL431 OTITLE="Word Reversing Program" pINSTRUCTIONS="Type a word or phrase you want to reverse: " OPRINT TITLE
pPRINT " "
OWHILE PHRASE<),'"' DO
OPRINT
OPRINT INSTRUCTIONS
OINPUT PHRASE
OHEGIN=LENCPHRASE)
OPRINT "This is how your phrase looks backwards:"
OFOR T=BEGIN TO 1 STEP -1
OPRINT MID$CPHRASE,T,1);
ONEXT T
OPR I NT
DENDWHILE
REND

11-121
BASIC09 Reference

PRINT USING Displays formatted text

Syntax: PRINT [#path] USING [format,] data[;data...]

Function: Prints data using a format you specify. This statement is especially useful for printing report headings, accounting reports, checks, or any document requiring a specific format. USING is actually an extension of the PRINT statement; therefore, the same rules that apply to the PRINT statement also apply to the PRINT USING statement (see PRINT).

Parameters:

path The number corresponding to an opened device
or file. If you do not specify pith, the default
is # 1, the video screen (standard output
device). To print to another device or file, first
OPEN a path to that file or device (see
OPEN).
format An expression specifying the arrangement of
the displayed data.
data Any numeric or string constant or variable.
Always enclose string constants within quota
tion marks. Each data item must be separated
by semicolons or commas.
Notes:

Each PRINT USING format specifier begins with a single identifier letter that specifies the type of format, as shown in the following table:

B Boolean format
E exponential format
H hexadecimal format r~
I integer format
R real format
S string format

11-122

BASIC09 Command Reference / 11

Follow the identifier letter with a constant number that specifies the field width. This number indicates the exact number of print

,,i-~ columns the output occupies. It must allow for both the data and

any overhead characters, such as sign characters, decimal points,

exponents, and so on.

Optionally, you can add a justification indicator to the format expression. The indicators are <, >, and ^. The meaning of these indicators varies, depending on the format type in which you use them. See the format type descriptions for specific information.

Note: Do not use any spaces within format expressions.

The following are the format type descriptions:

Real

Use this format for real, integer, or byte type numbers. The total field width specification must include two overhead positions for the sign and decimal point. The field width has two parts, separated by a period. The first part specifies the integer portion of the field. The second part specifies how many fractional digits to

,~^ display to the right of the decimal point.

If a number has more significant digits than the field allows, BASIC09 uses the undisplayed digits to round the number within the correct field width.

The justification modes are:

< Left justify with leading sign and trailing spaces. This is the default if you omit a justification indicator.

> Right justify with leading spaces and sign.

Right justify with leading spaces and trailing sign (financial format).

Some examples and their results are:

PRINT USING 1IR8.2<11,5678.123 5678.12

PRINT USING 1IR8.2>11,5678.123 5678.12

PRINT USING "R8.2>",12.3 12.30

PRINT USING "R8.2>",-555.9 -555.90

PRINT USING "R10.2^",-6722.4599 6722.46-

11-123

BASIC09 Reference

Exponential

Use this format to display real, integer, or byte values in the scientific notation format-using a mantissa and decimal exponent. The field has two parts: the first part must allow for six overhead positions for the mantissa sign, decimal point, and exponent characters.

The justification modes are:

< Left justify with leading sign and trailing spaces. This is the default if you omit a justification indicator.

Right justify with leading spaces and sign.

Some examples and their results are:

PRINT USING "E1 2. 3",1 234.567 1.235E+03
PRINT USING "E13.6>",-.001234 -1.234000E-03
PRINT USING "E18. 5>",1 23456789 1.23457E+08
Integer

Use this format to display integer, byte, or real type numbers in
an integer or byte format. The field width must allow for one
position of overhead for the sign.
The justification modes are:

< Left justify with leading sign and trailing spaces. This is the default if you omit a justification indicator.

Right justify with leading spaces and sign.

" Right justify with leading sign and zeroes. Some examples and their results are:

PRINT USING "I4<",10 10
PRINT USING "I4<",10 10
PRINT USING "I4^",-10 -010

Hexadecimal

Use this format to display any data type in hexadecimal notation. The field width specification determines the number of hexadecimal characters BASIC09 displays. If the data to display is string type, this function displays the ASCII value of each character in hexadecimal.

11-124

BASIC09 Command Reference / 11

The justification modes are:

< Left justify with trailing spaces. This is the default if you omit a justification indicator.

Right justify with leading spaces.

^ Center digits.

The number of bytes of memory used to represent data varies according to data type. The following chart suggests field widths for specific data types:

Memory Field Width
Type Bytes To Specify
Boolean and Byte 1 2
Integer 2 4
Real 5 10
String 1 per 2 times the string
character length

Some examples and their results are:

PRINT USING "H4",100 0064
PRINT USING "H4",-1 FFFF
PRINT USING "H81%--,--ABC" 414243

String

Use this format to display string data of any length. The field width specifies the total field size. If the string to display is shorter than the field size, PRINT USING pads it with spaces according to the justification mode. If the string to display is longer than the specified field width, PRINT USING truncates the right portion of the string.

The justification modes are:

< Left justify with trailing spaces. This is the default if you omit a justification indicator.

Right justify with leading spaces.

^ Center characters.

11-125

BASIC09 Reference

Some examples and their results are:

PRINT USING "S9<","HELLO" HELLO
PRINT USING "S9>","HELLO" HELLO
PRINT USING "S9^","HELLO" HELLO
Boolean

Use this format to display Boolean expression results. BASIC09
converts the result of the expression to the strings "True" or
"False." The format and results are identical to STRING formats.
The justification modes are:

< Left justify with trailing spaces. This is the default if you omit a justifcation indicator.

> Right justify with leading spaces.
" Center characters.
If A = 5 and B = 6, some examples and their results are:

PRINT USING "B9<",A<B True

PRINT USING "B9>",A>B Fa15e

PRINT USING "B9"",A=B Fa15e

Control Specifiers You can also use control specifiers within PRINT USING formats. The three specifiers are:

Tn Tab. n specifies a tab column at which to display
the next data.
Xn Spaces. n specifies a number of spaces to insert.
`text' Constant string. text is a string that is constant to
the format.
An example and its result is:

PRINT USING "'Addre55',X1,H4,X4,'Data',X1,H2",

1 000 ,1 00
Address 03E8 Data 64

11-126