XAWK

1
XAWK

• John Cieslewicz
• Shi Tak Man

Gabriela Cretu Prashant Puri
2
Introduction

• XAWK is inspired by the AWK programming language
  by Aho, et al.
• Goal Provide an easy to use XML processing
  language whose syntax resembles AWK
• Instead of matching text patterns (AWK), match
  patterns of XML elements (XAWK).

3
Language Features

• XML Pattern Matching (XPath)
• Associative Arrays
• Undeclared variables OK!

• Fully featured control statements
• for(x in array)
• Implicit promotion between strings and numbers
• Concatenation by juxtaposition

4
Example XML File

• ltstudentsgt
• ltgroup nameXAWKgt
• ltstudent fnameJohn mt45.0/gt
• ltstudent fnameGabriela mt88.9/gt
• ltstudent fnameShi Tak mt66.6/gt
• ltstudent fnamePrashant mt67/gt
• lt/groupgt
• lt/studentsgt

5
Example Grading Program

• /doc(roster.xml)/students/group/
• print Group name , _at_name
• /student/
• print Student name , CAfname
• print Midterm score , _at_mt

6
Grading with Descendent

• /doc(roster.xml)//group/
• print Group name , _at_name
• /student/
• print Student name , CAfname
• print Midterm score , _at_mt

7
More Language Examples

• j 0
• /student/
• name _at_fname
• studentNamej name
• gradesname _at_mt
• gradesname _at_final
• j

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XAWK Implementation
9
XAWK Implementation
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XAWK Testing

• ant build file for robust compiling and test
  execution
• Shell script for testing failure cases
• Test cases
• Pattern matching
• Control statements
• Arrays
• Mathematical and Relational Operators
• Concatenation
• Promotion

11
Conclusion and Lessons Learned

• Antlr can be made to do just about anything, but
  you might need a crowbar
• Testing is very important
• Coding in pairs helps catch errors and solve
  problems
• Constant code refactoring keeps it clear and
  clean
• Get to work early, make a good plan