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.
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I know this sounds confusing, as messing with quotations can often be, but in most cases it is easier to learn them by example.
However, it is a quite complex piece of software and this is sometimes exposed to users. This post is meant to be a guide to the available documentation and tutorials about CamlP4, assuming no previous experience with kanual. Support for the original syntax inside quotations was added in OCaml 3. The only thing to be aware of is that OCaml code inside quotations must use the revised syntax.
Domain-specific languages are a major application of Camlp4. As I mentioned, this is not a tutorial on CamlP4. Camlp4 is a software system for writing extensible parsers for programming languages.
If you know the revised syntax, you can start to use quotations to generate OCaml code. Back to the Revised syntax: If, instead, you simply quote the line of code above, CamlP4 will expand the quotation into the same AST. Grammars and Extensible Parsers CamlP4 makes it easy to create parsers, because it includes an embedded notation for parser generation. It is often used to write syntax extensions to OCaml, like adding support for a notation for monads or for list comprehensions.
Conceptually, the plan is simple: Daniel de Rauglaudre wrote the original CamlP4, which was available for OCaml since its early versions. camllp4
Camlp4 – Wikipedia
I hope this post helps people get up to speed in using this handy tool. Quotations allow the programmer to treat a piece of code as data instead of being part of the program itself. Camlp4 stands for Caml Preprocessor and Pretty-Printer and one of its most important applications is the definition of domain-specific extensions of the syntax of OCaml.
Actually, although the old CamlP4 had an official reference manual and tutorial, the new CamlP4 has neither. De Rauglaudre maintains a separate backward-compatible version, which has been renamed Camlp5.
A Camlp4 preprocessor operates by loading a collection of compiled modules cqmlp4 define a parser as well as a pretty-printer: It is also possible to define new printers, though most of the time this is not very useful. Filters and Printers So CamlP4 parses its input and then damlp4 an abstract syntax tree out of it. However, this has some disadvanges: The difference is only at the level of the concrete syntax, since these three versions are equivalent representations of the same abstract syntax tree.
The latter one is defined as an extension of the former, so you may need to consult both. CamlP4 gives OCaml programmers much of the power of metaprogramming available in Lisp languages, added with static type checking and customizable components.
If the target language is OCaml, simple syntax add-ons or syntactic sugar can be defined, in order to provide an expressivity which is not easy to achieve using the standard features of the OCaml language.
The abstract syntax tree is at the center cxmlp4 the syntax extensions, which are in fact OCaml programs.
The output of the program is as follows, showing that the fac function factorial only computes products that were not computed previously:. Part 2 and part 3 are about quotations from the perspective of a user, while part 8 and part 9 are about implementing mamual quotations and antiquotations. Other target languages can also be used, such as C.
From Wikipedia, the free encyclopedia. The user defines a grammar using a special notation, and CamlP4 generates a parser for it.
A (meta-)guide to CamlP4: Metaprogramming in OCaml
The intention manuak to give the Big Picture, so that the details can be worked out later. Quotations and Abstract Syntax Quotations allow the programmer to treat a piece of code as data instead of being part of the program itself.
All of the examples below are for Camlp5 or the previous version of Camlp4 versions 3.
The topics are presented in the best order IMO, of course for learning, under this assumption.