🚧 In the works

• Test version of BASIC Anywhere Machine
• Related draft version of Programming Reference and User Guide

New "View Code Issues" functionality

Details in this independent post: 

🚧 In the works: Code Issues Notification and Viewing

UrlQueryString$ function

This function returns the URL query string.

When a BAM program is exported as a stand-alone program, the URL to that HTML file can have a query string, providing us a way to pass any number of values to the BASIC program.

This is similar to command line parameters passed to an EXE.

This could also be a way of passing data to a BASIC program, via a URL to that program dynamically generated by something that wants to pass along data to the BASIC program.

Here's a sample program that shows and processes the query string:

• Run the program (parameters included in the URL)
• View the source code

PRINT "URL Query String: " + UrlQueryString$

 

UrlKey$ function

This is an include function (i.e. not built-into the interpreter, but rather a BASIC function meant to be included in programs if/when needed.)

Like this:

<<include "UrlKey$">>

The function as is currently implemented:

FUNCTION UrlKey$(key$)
  UrlKey$ = ""
  keyPos% = INSTR(ucase$(UrlQueryString$),{ucase$(key$) + "="})
  IF keyPos% THEN
    step1$ = RIGHT$(UrlQueryString$, LEN( UrlQueryString$ ) - keyPos% - LEN(key$) )
    step2% = INSTR(step1$, "&")
    UrlKey$ = IFF( step2%, LEFT$(step1$, step2% - 1 ), step1$)
  END IF
END FUNCTION

IFF function

Before IFF sample code:

FUNCTION GetUrlKey$(key$)
  GetUrlKey$=""
  keyPos%=INSTR(ucase$(UrlQueryString$),{ucase$(key$) + "="})
  IF keyPos% THEN
    step1$ = RIGHT$(UrlQueryString$, LEN( UrlQueryString$ ) - keyPos% - LEN(key$) )
    step2% = INSTR(step1$, "&")
    IF step2% THEN GetUrlKey$=LEFT$(step1$, step2% - 1 ) ELSE GetUrlKey$=step1$
  END IF
END FUNCTION

After IFF sample code:

FUNCTION GetUrlKey$(key$)
  GetUrlKey$ = ""
  keyPos% = INSTR(ucase$(UrlQueryString$),{ucase$(key$) + "="})
  IF keyPos% THEN
    step1$ = RIGHT$(UrlQueryString$, LEN( UrlQueryString$ ) - keyPos% - LEN(key$) )
    step2% = INSTR(step1$, "&")
    GetUrlKey$ = IFF( step2%, LEFT$(step1$, step2% - 1 ), step1$)
  END IF
END FUNCTION

Heads-up !!!  All three expressions in the function will all be evaluated every time that IFF function is executed.  So this function could be a performance hit (especially in a loop) if either or both TRUE and FALSE expressions are complex.  Best for these to be literals, constants, variables, or functions/expressions that are not complex (i.e. simple and quick to resolve.)  When dealing with complex expressions, better to go the traditional IF-THEN-ELSE route.

MIN and MAX functions

returnValue = MIN( expression1, expression2)

returnValue = MAX( expression1, expression2)

BIN$ function

BAM already had this function implemented as _BIN$ for compatibility with QB64/QB64pe.

Now:  if compatibility with QB64/QB64pe is not a concern, use either one you prefer.  Eventually, BIN$ will differ by having an optional second parameter: width.

DAY$ function

Returns the current day of the week in abbreviated form (SUN, MON, TUE, WED, THU, FRI, SAT)

DIV Operator

Integer division (an alternative to the already existing "\").

Whereas MOD returns the remainder after dividing two numbers, DIV returns the quotient after dividing two numbers.

FRAC function

returnValue = FRAC( numericExpression )

FRAC returns the fractional part of a number.

BETWEEN function

returnValue = BETWEEN( CheckedValue, MinValue, MaxValue)

CheckedValue, MinValue, and MaxValue can be any kind of expression that results in any one of the primitive data types (a string or any of the numeric data types).

If the CheckedValue is between MinValue and MaxValue, or equal to either MinValue or MaxValue, then BETWEEN returns -1 (i.e. TRUE);  Otherwise, BETWEEN returns 0 (i.e. FALSE).

CHOOSE function

returnValue = CHOOSE( ChoiceIndex%, ResultExpression1, ResultExpression2 [, ...])

• ChoiceIndex% is any kind of expression that results in any integer inclusively between 1 and the number of ResultExpression* parameters specified; if the expression results in an invalid number, the CHOOSE function will return nothing (0 assigned to a numeric variable, empty string to a string variable)

DEFtype Statements: Improved Compatibility

BAM's syntax for the DEFtype statements, as per original wwwBASIC  code:

DEFtype letter - letter [, letter - letter]

Unlike classic BASIC implementations, BAM did not allow single letters, allowing only letter ranges.

Now, BAM allows letter ranges and single letters, and a mixture of those declarations in one statement.

So for all DEFtype statements, the syntax:

DEFtype letterExpression [, letterExpression]

• type is one of the following: DBL, INT, LNG, SNG, STR
• letterExpression can be one of:
• a single letter
• a letter range consisting of two letters separated by a dash (i.e. a minus sign)
• startingLetter - endingLetter
• the range is inclusive
• this parameter is required
•  [, letterExpression]
• the square brackets says that more letterExpressions are optional: there can be none, one, or many. added after the first DEFtype parameter
• each occurrence must be preceded by a comma

Improvements to BIN$, _BIN$, HEX$, OCT$

All were mishandling non-integer numbers.  Now, all functions round numbers to integers before converting those to the other numeric system.

HEX$ and OCT$ were not converting negative numbers to negative number representations of the other systems.  BAM was effectively stripping the negative sign, converting the number, and then adding the sign as a prefix to the number.  The functions in the new version of BAM returns converted numbers the same way as GW-BASIC and QB64.

SLEEP Improvement

The SLEEP statement now allows for no parameter.  When no parameter is provided, the  program will pause until a keyboard key is pressed.

For QBASIC compatibility: if the parameter = 0, that will also cause the program to pause until a keyboard key is pressed. 

 

INSTR Improvement

Previously allowed only two parameters.  Now allows two or three parameters.

Syntax Options:

INSTR(baseString$, searchString$)

INSTR(start%, baseString$, searchString$)

WIDTH improvement

Fixed issue with console window not being quite right after WIDTH and until the browser window gets resized.

Also, a note: the WIDTH statement effectively changes the width of the console not only for text, but for graphics too.  So WIDTH(numberOfColumns%) sets the width of the console to numberOfColumns% * 8.

RANDOMIZE compatibility improvement

BAM previously required a parameter for the RANDOMIZE statement.  Now, BAM also accepts the RANDOMIZE statement without a parameter.

Although BAM ignores the RANDOMIZE statement (BAM's RND function does not need to be seeded), BAM does recognise and validate the statement for compatibility with other BASIC implementations.

Typically, when RANDOMIZE has no parameter, the program will pause and ask for a value.  BAM skips this.  

HEIGHT statement

Since seemingly forever BASIC has had the WIDTH statement to set the number of character columns on a screen, why not have a statement to specify the number of character rows?

PUTSTRING statement

The statement places a string on the screen at the specified x and y pixel coordinates.

INTEGER data type

"INTEGER" was previously treated by BASIC Anywhere Machine as equivalent to a LONG integer.

"DEFINT" defines variables that begin with a specified letter as SHORT integer.

To be consistent with DEFINT, and to be consistent/compatible with GW-BASIC, QBASIC, and QB64, "INTEGER" has been changed to be treated as equivalent to  SHORT integer.

SCROLL statement

Scroll the entire screen, or part of the screen either vertically, horizontally, or both.

 

Documentation: Adding Syntax Diagrams