Stefan Monnier's research while affiliated with Université de Montréal and other places

... In recent years, modal type systems based on this dual-context style have received renewed attention and provided insights into a wide range of seemingly unconnected areas: from reasoning about universes in homotopy type theory [30,38] to mechanizing meta-theory [36,37], to reasoning about effects [40], and meta-programming [27]. This line of work builds on the dual-context formulation of Pfenning and Davies. ...

... A related body of work has used regions as a low-level primitive on which to build type-safe garbage collectors [20][21][22]. Each of these approaches requires non-lexical regions, since, in a copying collector, the from-and to-spaces have non-nested lifetimes. ...

... subst. in a neutral producing a neutral term. (Belanger et al., 2013), or normalization by evaluation for the simply typed λ-calculus (Cave and Pientka, 2012). ...

... Another interesting implementation has been carried out in Beluga [22], a functional programming language that is based on contextual modal type theory and that supports higher-order abstract syntax [21]. Rich properties of programs can be embedded in types in Beluga and [5] shows how this feature can be exploited to ensure type preservation. It remains to be seen if types can also be used to encode semantics preservation. ...

... Here, we can (potentially) exploit code generation via the Autosubst framework to ease the definition of the initial infrastructure. In fact, contextual objects may be viewed as an abstraction of well-typed de Bruijn encodings (Hofmann, 1999) and can actually be compiled to well-typed de Bruijn (Ferreira et al., 2013). Thus one could approximate some of Beluga's features through code generation (Kaiser et al., 2017) and Coq's rewriting facilities. ...

... Typically, artifacts of later phases are created from higher-level artifacts of the previous phases, but dependencies are not linear and difficult to trace: Diverse analysis requirements, platform constraints and modeling acts such as architectural decisions , pattern applications, etc. manifest themselves in later artifacts. While the knowledge about these manifestations is available at the point of decision-making, this information often is not part of a SE process [10]. Instead, such information has to be recorded in additional documentation which accompanies the process. ...

... Although the ideas behind the encodings are inspired by dependently typed programs, the code does not look like code in any full-spectrum dependently typed language, such as Cayenne [Augustsson 1998], Coq [Coq development team 2004], Epigram [McBride 2004], or Agda [Norell 2007]. As a result, several authors [Guillemette and Monnier 2008b; McBride 2002; Neubauer and Thiemann 2002] have pushed for more direct mechanisms , and GHC implementors have responded with Generalized Algebraic Datatypes (GADTs) [Cheney and Hinze 2002; Peyton Jones et al. 2006; Schrijvers et al. 2009; Xi et al. 2003] , typelevel functions [Chakravarty et al. 2005], and type-level datatypes with kind polymorphism [Yorgey et al. 2012]. These additions provide native support for constrained data (replacing the use of phantom types, nested datatypes, and type equality encodings) and type-level computation (replacing the use of logic programming with type classes and functional dependencies). ...

... It is not clear to us whether, in practice, one can get away with only, say, homogeneous regions. Monnier (2008) introduces an interesting hybrid that subsumes homogeneous and heterogeneous regions. Boyland (2010) describes nesting, a mechanism by which one permission can become (irreversibly) nested within another permission. ...

... However, it is not always easy that a Simple Scalar model can be made to implement latest parallel micro architectures without doing any modifications in the underlying morphology. Still two Simple Scalar Siddons were developed to adapt multithreading in the SSMT [9] and M-Sim [10] simulators. These tools are suitable to fabricate designs stationed on simultaneous multithreaded processors, with the constraint of implementing a set of workloads progressively. ...

... To demonstrate the macro system, consider the desugaring of the n-ary And (&&) function as implemented within the compiler: [18] is also performed as part of the binding analysis. Escaped variables are annotated and are used during closure conversion [35,73]. ...