构建使用列表理解的OCaml代码 [英] Building OCaml code that uses list comprehension

问题描述

从这个SO问题中:在Ocaml中进行列表理解?，我可以安装理解包opam install pa_comprehension，并在顶级REPL中使用该软件包.

From this SO question: List Comprehension in Ocaml?, I could install the comprehension package with opam install pa_comprehension, and use the package in toplevel REPL.

# #require "pa_comprehension";;
# open Batteries;;
# [? 2 * x | x <- 0 -- max_int ; x * x > 3 ?];;
- : int Batteries.Enum.t = <abstr>

然后，我该如何编译代码?

Then, how can I compile the code?

推荐答案

不幸的是，由于pa_comprehension软件包名称不以.syntax扩展名结尾，因此这比应做的要难一些. (此问题仍未得到解决的事实表明，在现代OCaml中使用pa_comprehension并不十分流行).因此，如果没有适当的扩展，我们需要手动进行所有操作.如果您的文件名为pr.ml，则正确的调用是:

Unfortunately, since pa_comprehension package name is not ended with .syntax extension, this is a little bit harder than it should be. (The fact that this issue is still not fixed, shows that using pa_comprehension is not very popular in modern OCaml). So, without the proper extension, we need to do everything manually. If your file is named pr.ml, then the correct invocation is:

$ ocamlbuild -use-ocamlfind -syntax camlp4o -pkg camlp4,pa_comprehension pr.native

如果不想每次都键入它，则可以创建具有以下内容的_tags文件:

If you don't wan't to type it every time, then you can create _tags file, with the following contents:

$ cat _tags
<**/*> : package(camlp4),syntax(camlp4o),package(pa_comprehension)

在这种情况下，命令行拼写要简单一些:

In that case, the command line spell is a little bit easier:

$ ocamlbuild -use-ocamlfind pr.native

这篇关于构建使用列表理解的OCaml代码的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！