June 6, 2019 posted by

Contribute to ocaml/camlp4 development by creating an account on GitHub. #toc Camlp4 is part of the standard OCaml distribution and Camlp5 is distributed separately. name change. Camlp5 Reference Manual (by Daniel de Rauglaudre). Camlp4 stands for Caml Preprocessor and Pretty-Printer and one of its most important applications is the definition of domain-specific.

Author: Malkis Kijar
Country: Mongolia
Language: English (Spanish)
Genre: Medical
Published (Last): 12 December 2009
Pages: 29
PDF File Size: 8.52 Mb
ePub File Size: 15.49 Mb
ISBN: 454-5-34458-771-8
Downloads: 97838
Price: Free* [*Free Regsitration Required]
Uploader: Dalabar

Any loaded cmlp4 can extend a grammar defined in another module, and an extension can not only add new productions, but also change existing ones or even delete them. Most of them are linked in a previous part.

Camlp4 includes a domain-specific language as it provides syntax extensions which ease the development of syntax extensions. They are widely used in Lisp because of its uniform representation for code and data, and are widely used when programming in CamlP4 because they make it easier to generate code.

They would all converge to an abstract syntax tree in a unique format that a compiler can handle.

The Camlp4 syntax extension

Many factors contribute to this. Furthering the difficulties, it is now fragmented CamlP4 and CamlP5 and not very well documented.

Instead, each template has gaps that must be filled with data which depends on the situation. It provides a set of OCaml libraries that are used to define grammars as well as loadable syntax extensions of such grammars. This is basic in code generation: CamlP4 is mostly used as a metaprogramming tool for OCaml, but it can be used in many ways: Memoization consists in storing the results of previous computations in a table so that the actual computation of the function for each possible argument occurs at most once.


Retrieved from ” https: This page in the CamlP4 wiki has a good overview about using CamlP4 by itself and together with a compiler. This AST will be emitted, or printed, in a chosen format.

Camlp4 – Wikipedia

Filters and Printers So CamlP4 parses its input and then builds an abstract syntax tree out of it. I just found out about it as I was almost finished ca,lp4 this post. Quotations also allow for antiquotations, which are parts of a quotation that should be evaluated instead of directly transformed to AST nodes.

Other target languages can also be used, such as C. As I mentioned, this is not a tutorial on CamlP4.

CamlP4 has an embedded notation for parser generation. As this list shows, it is a very powerful and useful tool for parsing and metaprogramming. And now for the punchline: The difference is only at the level of the concrete syntax, since these three versions are equivalent representations of the same abstract syntax tree. So a fork ensued: The marshaled tree also includes location information, which allows the compiler to report errors correctly for the input source.

Jake Donham probably knows a lot more about this stuff than me, but sometimes he seems to be writing to people who already know about CamlP4, especially in the first few posts. Although the definition of grammars must be done in OCaml, the parser that is being defined or extended is not necessarily related to OCaml, in which case the syntax tree that is being manipulated is not the one of OCaml.

This can be used for defining parsers or extending existing ones. You could feed the output of the pretty-printer to the OCaml compiler, thus effectively activating the syntax extension. CamlP4 makes it easy to create parsers, because it includes an embedded notation for parser generation. Daniel de Rauglaudre wrote the original CamlP4, which was available for OCaml since its early versions.


To learn how to use quotations to generate OCaml AST nodes, you can look at this appendix from the same manual.

A (meta-)guide to CamlP4: Metaprogramming in OCaml

So CamlP4 parses its input and then builds an abstract syntax tree out of it. However, there is a good source of examples of the revised syntax: CamlP4 uses an alternative concrete syntax for OCaml.

A Camlp4 preprocessor operates by loading a collection of compiled modules which define a parser as well as a pretty-printer: It provides a new keywordmemowhich can be used as a replacement for function and provides automatic memoization of functions with pattern matching. This brings up another source of confusion: The only thing to be aware of is that OCaml code inside quotations must use the revised syntax. However, it is a quite complex piece of software and this is sometimes exposed to users.

Conceptually, the plan is simple: For example, this piece of code: To extend the OCaml parser, it may be useful to take a look at how it is defined for the standard syntax es. This CamlP5 tutorial by Martin Jambon is very good. The series of posts on CamlP4 over at Ambassador at the Computers is a good source, with manuual caveats. The maanual about the Revised syntax in the latest official reference manual for the old CamlP4 version 3.