NOCC: Guppy Implementation

This page contains some notes about the Guppy implementation within NOCC. There is no formal language documentation, yet. There is some informal documentation here: http://frmb.org/guppy.html.

fetrans spaghetti

Guppy adds a couple of extra front-end passes to the compiler, that do much of the work of transforming the Guppy language structure into something that can be code-generated into C (assuming the default CCCSP back-end). All of the front-end transforms are done target-unaware. Back-end transforms are used in one or two places to handle things prior to name-mapping (where most of the target-dependent stuff happens).

• fetrans:

  • par: create process abstractions and instances for parallel processes.

  • fcndef: create process abstraction of function if needed (result-less processes only).

• fetrans1:

  • alt: create temporary to hold selected guard index.

  • fcndef: parameterise results.

  • instance: pull apart into temporaries and assignments.

  • cflow: turn return statements into assignments and return.

  • io: create temporaries for non-addressable things (typically constants and expressions).

  • litstring: create temporary.

• fetrans15:

  • name: remove lonely names (discarded expressions, particularly from instance fiddling in fetrans1).

• fetrans2:

  • assign: from instance, push LHS into result parameters.

• fetrans3:

  • io: dismantle complex outputs into sequenced events.

  • alt: breaks into alt then choice on selection.