XTRAN Example — Tally RPG Statement Types

Scenario -- you're the software development manager for an RPG shop, and you want to monitor your developers' use of RPG's statement types, to ensure they're taking advantage of the useful ones and avoiding those that might be problematic.

XTRAN to the rescue!

The following example uses an XTRAN rules file comprising only 21 non-comment lines of "meta-code" (XTRAN's rules language) to tally the occurrence of statement types in RPG.

These rules are not specific to RPG; they can be used unchanged to tally statement type occurrences in any language.

We then use another set of XTRAN rules, comprising 77 noncomment lines, to format the results into a report. Because these rules manipulate only text, the XTRAN version used is "rules only". NOTE that these rules can report any kind of tallies, regardless of the source.

The code mining rules for this example can easily be enhanced to produce DSV output that can be interactively queried using existing XTRAN rules.

How can such powerful and generalized code analysis and reporting be automated in only 98 total code lines of XTRAN rules? Because there is so much capability already available as part of XTRAN's rules language. These rules take advantage of the following functionality:

Text file input and output
Text manipulation
Environment variable manipulation
Regular expression matching
Delimited list manipulation
Content-addressable data bases
"Per statement" recursive iterator
Access to XTRAN's Internal Representation (XIR)
XIR's language-independent properties

The input to and output from XTRAN are untouched.

Process Flowchart

Here is a flowchart for this process, in which the elements are color coded:

BLUE for XTRAN versions (runnable programs)
ORANGE for XTRAN rules (text files)
RED for code
PURPLE for text data files

Input to XTRAN:

00100C           FUNC      BEGSR
00200C                     MOVE 1         FLD2
00300C           FLD1      IFEQ 1
00400C           FLD2      IFEQ 1
00500C           FLD2      ADD  1         FLD2
00600C           FLD2      IFLE 1
00700C           1         ADD  FLD2      FLD2
00800C                     END
00900C                     ELSE
01000C           FLD1      IFGT 1
01100C           1         ADD  FLD2      FLD2
01200C                     END
01300C           1         ADD  FLD2      FLD2
01400C                     END
01500C                     END
01600C           FLD2      ADD  1         FLD2
01700C                     ENDSR

Output from XTRAN code analysis rules:

ADD,5
BEGSR,1
ELSE,1
END,4
ENDSR,1
IFEQ,2
IFGT,1
IFLE,1
MOVE,1

Output from XTRAN tally reporting rules:

                           RPG Statement Type Tallies

ADD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .     5
BEGSR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .     1
ELSE  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .     1
END . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .     4
ENDSR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .     1
IFEQ  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .     2
IFGT  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .     1
IFLE  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .     1
MOVE  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .     1