Pattern Matching and Match Statements

[Sunjay Varma]

Pretty much required to make #41 usable.

• new match statement added to grammar
• pattern matching on struct fields, tuples, enum variants, etc.
• Ignore struct fields with ..
• Wildcard _ or identifier to match all
• Multiple patterns separated by |
• Bind names with @
• irrefutable patterns can be used in assignment or as function parameters

Reference:

• https://doc.rust-lang.org/book/patterns.html