Vaxscan (#4049)

* Adding vaxscan ANTLR4 parser

* Update README.md

* Adding desc.xml file and changed alt to alt_ to avoid conflicts.

* Remove the spurious lexer rules for some of the string literals.

* Grammar reformatted using antlr-format tool.

* Adding pom.xml file for maven

---------

Co-authored-by: William Cox <bill@dev-ubuntu-vm>

vaxscan/README.md

@@ -0,0 +1,49 @@
+This is the grammar for VAX SCAN. The following description is lifted from the
+Guide to VAX SCAN (Copyright ©1985, 1986, 1989 by Digital Equipment 
+Corporation).
+
+"VAX SCAN is a block-structured programming language in the
+VAX/VMS environment that is designed to build tools to manipulate
+text strings and text files. The primary applications for VAX SCAN are
+filters, translators, extractors/analyzers, and preprocessors."
+
+Digital Equipment (DEC) having decided not to continue the product or port
+it to their new hardware platforms (ALPHA and Itanium) made the source
+code FREEWARE.
+
+This ANTLR4 grammar is based on the BNF provided in the source code.
+
+The following copyright statement is used throughout the source code. As they
+copied the source directory tree and provided it AS-IS I would assume this no
+longer applies.
+
+******************************************************** 
+                COPYRIGHT  1989, 1996
+            DIGITAL EQUIPMENT CORPORATION, MAYNARD, MASS.
+
+THIS SOFTWARE IS FURNISHED UNDER A LICENSE AND MAY BE USED AND COPIED ONLY IN ACCORDANCE WITH THE TERMS OF SUCH  LICENSE
+AND  WITH THE INCLUSION OF THE ABOVE COPYRIGHT NOTICE.  THIS SOFTWARE OR ANY OTHER COPIES THEREOF MAY NOT BE PROVIDED OR
+OTHERWISE MADE AVAILABLE TO ANY OTHER PERSON.  NO TITLE TO AND OWNERSHIP OF THE SOFTWARE IS HEREBY TRANSFERRED.
+
+THE INFORMATION IN THIS SOFTWARE IS SUBJECT TO CHANGE WITHOUT NOTICE AND SHOULD NOT BE  CONSTRUED  AS  A  COMMITMENT  BY
+DIGITAL EQUIPMENT CORPORATION.
+
+DIGITAL  ASSUMES  NO  RESPONSIBILITY  FOR  THE  USE OR RELIABILITY OF ITS SOFTWARE ON EQUIPMENT WHICH IS NOT SUPPLIED BY
+DIGITAL.
+
+*********************************************************
+
+The source code along with VAX/VMS binaries are available on the VMS Software
+Inc (VSI) website under Freeware.
+
+https://vmssoftware.com/community/freeware/
+
+The source code is a mix of Bliss, PLI, and Macro Assembler. The compiler uses
+a code generator (VAX Code Generator) that will create VAX/VMS object files.
+Bliss is a family of compilers across several DEC platforms. It was designed as
+a systems implementation language.
+
+Under the examples directory are a number of small sample programs that were
+provided with the software kit. They all parse cleanly.
+
+

vaxscan/desc.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<desc xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../_scripts/desc.xsd">
+   <antlr-version>^4.10</antlr-version>
+   <targets>Antlr4ng;CSharp;Cpp;Dart;Go;Java;JavaScript;PHP;Python3;TypeScript</targets>
+   <inputs>examples</inputs>
+</desc>

vaxscan/examples/caps.scn

@@ -0,0 +1,93 @@
+!
+!			  COPYRIGHT (c) 1989 BY
+!	      DIGITAL EQUIPMENT CORPORATION, MAYNARD, MASS.
+!
+! THIS SOFTWARE IS FURNISHED UNDER A LICENSE AND MAY BE USED AND  COPIED
+! ONLY  IN  ACCORDANCE  WITH  THE  TERMS  OF  SUCH  LICENSE AND WITH THE
+! INCLUSION OF THE ABOVE COPYRIGHT NOTICE.  THIS SOFTWARE OR  ANY  OTHER
+! COPIES  THEREOF MAY NOT BE PROVIDED OR OTHERWISE MADE AVAILABLE TO ANY
+! OTHER PERSON.  NO TITLE TO AND OWNERSHIP OF  THE  SOFTWARE  IS  HEREBY
+! TRANSFERRED.
+!
+! THE INFORMATION IN THIS SOFTWARE IS SUBJECT TO CHANGE  WITHOUT  NOTICE
+! AND  SHOULD  NOT  BE  CONSTRUED  AS  A COMMITMENT BY DIGITAL EQUIPMENT
+! CORPORATION.
+!
+! DIGITAL ASSUMES NO RESPONSIBILITY FOR THE USE OR  RELIABILITY  OF  ITS
+! SOFTWARE ON EQUIPMENT WHICH IS NOT SUPPLIED BY DIGITAL.
+!
+
+MODULE process_basic_identifiers;
+
+    !+
+    !   This SCAN program will transform a BASIC program
+    !   printing all the BASIC keyword in upper case and 
+    !   printing all the identifiers in lower case
+    !-
+
+    SET alpha	( 'a'..'z' OR 'A'..'Z' );
+    SET other	( alpha OR '0'..'9' OR '$' OR '_' OR '.' OR '%' );
+
+    TOKEN id	{ alpha [ other ]... };
+
+    DECLARE keyword: TREE( string ) OF INTEGER;
+
+    MACRO match_id TRIGGER { id_text: id };
+
+	IF EXISTS( keyword( UPPER( id_text ) ))
+	THEN
+	    ANSWER UPPER( id_text );
+	ELSE
+	    ANSWER LOWER( id_text );
+	END IF;
+
+    END MACRO;
+
+    PROCEDURE process_ids MAIN;
+
+    !+
+    !   This is a representative list of BASIC keywords.
+    !   You can add more if you desire.
+    !-
+
+	keyword( 'TYPE' ) = 0;
+	keyword( 'EXPLICIT' ) = 0;
+	keyword( 'DECLARE' ) = 0;
+	keyword( 'INTEGER' ) = 0;
+	keyword( 'CONSTANT' ) = 0;
+	keyword( 'STRING' ) = 0;
+	keyword( 'EDIT$' ) = 0;
+	keyword( 'ON' ) = 0;
+	keyword( 'ERROR' ) = 0;
+	keyword( 'GOTO' ) = 0;
+	keyword( 'OPEN' ) = 0;
+	keyword( 'FOR' ) = 0;
+	keyword( 'INPUT' ) = 0;
+	keyword( 'AS' ) = 0;
+	keyword( 'OUTPUT' ) = 0;
+	keyword( 'NOMARGIN' ) = 0;
+	keyword( 'WHILE' ) = 0;
+	keyword( 'LINPUT' ) = 0;
+	keyword( 'OR' ) = 0;
+	keyword( 'POS' ) = 0;
+	keyword( 'LEFT$' ) = 0;
+	keyword( 'RIGHT$' ) = 0;
+	keyword( 'SEG$' ) = 0;
+	keyword( 'LEN' ) = 0;
+	keyword( 'END' ) = 0;
+	keyword( 'NEXT' ) = 0;
+	keyword( 'PRINT' ) = 0;
+	keyword( 'CLOSE' ) = 0;
+	keyword( 'RESUME' ) = 0;
+	keyword( 'OPTION' ) = 0;
+	keyword( 'IF' ) = 0;
+	keyword( 'THEN' ) = 0;
+	keyword( 'ELSE' ) = 0;
+
+	START SCAN
+	    INPUT FILE  'caps.bas'
+	    OUTPUT FILE 'new_caps.bas';
+
+    END PROCEDURE;
+
+END MODULE;

vaxscan/examples/comment.scn

@@ -0,0 +1,33 @@
+MODULE recognize_comment;
+
+!+
+!    This module recognizes PL/I or C style comments of the form:
+!
+!		/* anything_but_star_slash...  */
+!-
+
+    SET NON_star ( NOT '*' );
+    SET NON_star_or_slash ( NOT ( '*' OR '/' ) );
+
+    TOKEN comment { '/*'
+		    [ NON_star | '*'... NON_star_or_slash ]... 
+		    '*'... '/' };
+
+    MACRO do_comment TRIGGER { r : comment};
+	WRITE 'The comment is: ', r;
+	END MACRO;
+
+    PROCEDURE main_routine MAIN (  );
+
+    !+
+    !    Specify the DATA STACK clause so we can recognize longer comments,
+    !    since they can span multiple lines.
+    !-
+
+	START SCAN
+		DATA STACK 4096
+		OUTPUT FILE 'NL:';
+
+	END PROCEDURE;
+
+END MODULE;

vaxscan/examples/compress.scn

@@ -0,0 +1,26 @@
+module compress_blanks;
+
+    !+
+    !   This SCAN program will read the file bound to the logical name
+    !   SCN$INPUT.  One or more tabs or spaces found in the file will
+    !   be compressed to a single space.  The result of the translation
+    !   is placed in the file bound to the logical name SCN$OUTPUT.
+    !-
+
+    token blanks	{ { ' ' | s'ht' }... };
+
+    macro compress trigger { blanks };
+
+    	answer ' ';
+
+    end macro;
+
+    procedure main main;
+
+    	start scan 
+	    input file 'scn$input'
+	    output file 'scn$output';
+
+    end procedure;
+
+end module;