PicLan-IP Pre-compiler Usage

PicLan-IP parses mv/Basic source code through a parsing "pre-compiler". This pre-compiler extends the mv/Basic language to include a number of elements that make web development easier. These elements include:

Pre-defining global EQUATES and COMMON
Defining additional mv/Basic functions
Defining additional mv/Basic statements

If you are writing mv/Basic application code as a part of an HTML page, then the code that you write will be processed by the pre-compiler and you need to be aware of it's behavior and limitations. If you are calling external subroutines from within your HTML page, you may want to compile those subroutines with the pre-compiler as well so that they may make use of PicLan-IP mv/Basic extensions.

mv/Basic EQUATES

The PicLan-IP pre-compiler will define the following constants:

      EQUATE AM          TO CHAR(254)
      EQUATE VM          TO CHAR(253)
      EQUATE SVM         TO CHAR(252)
      EQUATE SEPAR.CHAR  TO CHAR(249)
      EQUATE ESC         TO CHAR(27)
      EQUATE CR          TO CHAR(13)
      EQUATE FF          TO CHAR(12)
      EQUATE LF          TO CHAR(10)
      EQUATE BS          TO CHAR(8)
      EQUATE BELL        TO CHAR(7)
      EQUATE NUL         TO CHAR(0)
*
      EQUATE YES         TO 1
      EQUATE NO          TO 0
*
      EQUATE DAYS        TO 'Sun]Mon]Tue]Wed]Thr]Fri]Sat'

mv/Basic COMMON

The pre-compiler itself does not define any COMMON variables, but HTML docoments use a number of common elements in their processing. If you are writing mv/Basic subroutines that need to use PicLan-IP extensions, then you must include a number of items with the mv/Basic source code. As of this documentation, you need to include the following items:

INCLUDE PLIP.BP SYS.TYPE.INCLUDE
INCLUDE PLIP.BP PL.COMMON
INCLUDE PLIP.BP PL.COMMON.DEFS
INCLUDE PLIP.BP PL.DEFS
INCLUDE PLIP.BP PLIP.COMMON
INCLUDE PLIP.BP PLW.COMMON

Future releases of PicLan-IP may change these common areas, so you should be careful when upgrading PicLan-IP. You can verify the current PicLan-IP COMMON usage by looking at the generated source code in WWW.CTRL,PGBASIC.

Pre-compiler Usage

The PicLan-IP pre-compiler is designed to be an easy replacement for the BASIC (or COMPILE) verb. The format of the pre-compiler TCL command is:

PC filename item{ item ...} {=options}

You can also specify items with an active select list or use an asterisk to indicate all items in the file.

options:

There are also some options that are platform specific:

AP/Pro:

=V - use the COMPILE verb instead of the BASIC verb

D3:

How the pre-compiler works

The pre-compile operates by translating your mv/Basic source code into a second "intermediate source code". This intermediate source code is then compiled with the system BASIC (or COMPILE) command.

The intermediate source code is temporarily stored in a second data portion of the data file that contains the original source code. If you have a basic program file named BP, then the intermediate source code will be stored in BP,COMPILE.SOURCE. With normal usage the intermediate source code is deleted by the pre-compile immediately after the system compiler completes.

The intermediate source code is carefully constructed to behave as much like the original source code as possible:

mv/Basic commands that do not use PicLan-IP extensions are passed through without modifications.
mv/Basic commands that include PicLan-ip extensions are always built on a single line so that the original source code line numbering will be valid for the system object code.

Limitations of the pre-compiler

The pre-compiler does have some limitations. In general, the pre-compiler is very good at processing all legal mv/Basic code constructions with the exception of:

Single-line THEN/ELSE clauses.

READ X FROM DATA.FILE , ID ELSE X = PL_AMTOCRLF(Z)

READ X FROM DATA.FILE , ID ELSE

X = PL_AMTOCRLF(Z)

END

Delimiters in quoted strings.

Do not use system delimiters such as value or sub-value marks directly within quoted strings if the string occur on the same line as PicLan-IP extensions.