如何通过自制软件安装composer

我是MacOS的新手,所以这可能是一个简单的问题.

我正在使用安装了默认PHP 7.1的High Sierra,我还安装了PHP 7.2运行：

curl -s http://PHP-osx.liip.ch/install.sh | bash -s 7.2

当我跑：

brew install composer

我越来越：

Error: No available formula with the name "composer" 
==> Searching for a prevIoUsly deleted formula...
Warning: homebrew/core is shallow clone. To get complete history run:
  git -C "$(brew --repo homebrew/core)" fetch --unshallow

Error: No prevIoUsly deleted formula found.
==> Searching for similarly named formulae...
==> Searching local taps...
Error: No similarly named formulae found.
==> Searching taps...
==> Searching taps on GitHub...
Error: No formulae found in taps.

问题是如何通过自制软件安装作曲家？ (也许我应该以某种方式卸载PHP我已经安装并通过自制软件安装PHP？)

解决方法:

现在可以安装运行的composer

brew install composer

以前的答案(旧版本)：

似乎解决方案正在运行：

brew tap homebrew/homebrew-PHP

然后

brew install composer

在那个作曲家好像被安装之后：

composer --version
Composer version 1.5.5 2017-12-01 14:42:57