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A-Shell Consolidated Reference

The /X:1 switch (or equivalently, COMPLP) extends the compiler support to include certain statements which were originally implemented by BASICplus; these are listed below. Refer to the BASICplus User's Manual for more details on these language features.

Note that although A-Shell supports these BASICplus language extensions in source code, in no way does it support the .RP (compiled BASICplus) file format. Instead, it compiles them as non-standard extensions to the .RUN format, and any such .RUN files will not be compatible with RUN.LIT or RUNP.LIT under AMOS. Thus, if you choose to use these language extensions and want to run them under both A-Shell and AMOS, you will have to recompile the source on both platforms.

The /RC (Run Compatible) on COMPIL, when used in place of the /X:1 or /X:2 switch, allows many of these extensions to be compiled into a RUN format that remains compatible with AMOS. In the following table, the "/RC?" column says whether, when compiling with the RC switch, use of this statement or feature will produce a run file that is run compatible ("RC") with AMOS.  

Extension

/RC?

Meaning

AMOS

 

Execute AMOS commands as subroutines

CMDLIN

 

Retrieve command line

DEFINE

Yes

Define a symbolic constant

UNDEF

 

Cancels (undefines) a symbol created by a prior DEFINE or DEFALIAS directive

DIVIDE’BY’0

 

Determine how to handle divide by zero

DO LOOP

Yes

Repeat loop while (or until) a condition is (or becomes) true.

EDIT$()

 

String editing function

ERRMSG(x)

 

Returns the text of the error message associated with the specified error number (from the SYS:ERRMSG.xxx file).

EXIT

Yes

May be placed inside of a DO...WHILE or For ... Next loop to cause an immediate exit of the loop.

FILL$()

 

Copies the given expression, partially or multiple times, up to the specified length.

FOR … NEXT

Yes

Traditional loop structure using a loop counter.

GETKEY

 

Input a character

Hex, Octal, ASCII Values

Yes

Specifying literal values in an alternate radix

I variable type

 

Integer variable type

IF / ENDIF

Yes

IF <condition> THEN
   statements
ENDIF

INPUT RAW

 

Raw input, from file channel or keyboard, into X variables.

ISAM’INDEXED {‘EXCLUSIVE}, ISAMP’INDEXED {‘EXCLUSIVE}

Yes

These file type specifiers may be used in file OPEN statements to clarify if the file is to be handled as ISAM 1.x or ISAM-A. See /I switch above. Note that this applies to AlphaBASIC 1.4 as well as BASICplus.

LOOKUP ("fspec")

 

Similar to LOOKUP but returns file size as value of expression. Note that a zero block file returns 0.5.

ODTIM()

 

Day / Time output conversion/formatting

OPEN for APPEND

 

Enhancement to OPEN #CH, FSPEC, APPEND

PRAGMAS

 

See ++PRAGMAs in A-Shell Extensions.

READ'ONLY

 

File open mode modifier

REPEAT

Yes

Jump to top of loop structure to begin next iteration

STRIP(var) or STRIP$(var)

 

Returns var with all trailing spaces removed.  

 

Yes

Conditional execution based on value of an expression.