Abstract Syntax Tree (PAST)

Once we have a parse tree, we convert it to an abstract syntax tree.

An abstract syntax tree is a de-sugared form of the program code.

Currently there are at least three separate implementations of "PAST" in Parrot:

• punie/pheme has one(?)
• perl6 has another
• APL has yet another

The separate implementations simply reflect compilers that were started at different phases of compiler tool development.

Eventually they'll be unified -- we're still exploring the design space.