In this paper, we present a type system for typing Web applications in SMLserver, an e#cient multi-threaded Web server platform for Standard ML scriptlets. The type system guarantees that only conforming XHTML documents are sent to clients and that forms are used consistently and in a type-safe way. The type system is encoded in the type system of Standard ML using so-called phantom types.

WASH/CGI is an embedded domain-specific language for server-side Web scripting. Due to its reliance on the strongly typed, purely functional programming language Haskell as a host language, it is highly flexible and—at the same time—it provides extensive guarantees due to its pervasive use of type information. WASH/CGI can be structured into a number of sublanguages addressing different aspects of the application. The document sublanguage provides tools for the generation of parameterized XHTML documents and forms. Its typing guarantees that almost all generated documents are valid XHTML documents. The session sublanguage provides a session abstraction with a transparent notion of session state and allows the composition of documents and Web forms to entire interactive scripts. Both are integrated with the widget sublanguage which describes the communication (parameter passing) between client and server. It imposes a simple type discipline on the parameters that guarantees that forms posted by the client are always understood by the server. That is, the server never asks for data not submitted by the client and the data submitted by the client has the type requested by the server. In addition, parameters are received in their typed internal representation, not as strings. Finally, the persistence sublanguage deals with managing shared state

We exhibit the rationale behind the design of Epigram, a dependently typed programming language and interactive program development system, using refinements of a well known program—merge sort—as a running example. We discuss its relationship with other proposals to introduce aspects of dependent types into functional programming languages and sketch some topics for further work in this area. 1.

In this paper, we present a type system for typing Web applications in SMLserver, an e#cient multi-threaded Web server platform for Standard ML programs. The type system guarantees that only conforming XHTML documents are sent to clients and that the target scriptlets of client-submitted forms use form data consistently and in a type-safe way.

Abstract—J % (J-mod), is a Java language extension that supports integration with Domain-Specific Languages. The integration is realized through an architecture that permits external modules to support DSLs. The DSL statements can be syntactically checked at compile-time. An additional facility allows the static type checking of Java variables that appear within DSL code. To support this process each DSL module comes as a library that is used both at compile time and during program execution. I.