E language Interpreter (Scala)
E Language Definition
Implementation Specs
- For ill-typed inputs, you can return arbitrary values, or raise exceptions.
- X* denotes that X can appear 0 or more times.
- let clauses create a new scope like a `block' in Scala. Name bindings def, and val work the similar way as in Scala.
- { (def f (A*) E) assigns name f to expression E with arguments
- A*. Examples include (def f (a b) (+ a b)) and (def g () 3).
- { (val x E) assigns name x to the value obtained by evaluating E.
- { We do not allow the same name to be defined twice in the frame.
- { You do not have to consider forward reference in val. For example, (val x (cons 1 x)).
- { Hint: Implement environment with mutable data structure for lazyness.
- Enviornment is collection of Frames. Frame is created when a new scope is created.
- (nil? E) first evaluates E into value v. If v is nil, it returns true. Otherwise, it returns false.
- For additional information, post questions on the GitHub course webpage.
- examples in src/test/scala/TestMain.scala.
- Optimize interp to handle tail recursive input programs
- Add lazy evaluation to interp by implementing by-name and lazy-val
- Add record to interp by implementing rmk and rfd following.
- rmk and rfd implement record types.
- { (rmk B*) constructs a record value.
- { (rfd E x) projects out the field x of the record value obtained by evaluating E.