opam为什么不能安装图形包？

Question

我尝试安装 ocaml 图形包，但它失败了。关于如何修复它的任何建议？

~/Documents/Work/Code/OCaml with graphics: opam update

=-=- Updating package repositories =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=  ???? 
[default: http] Command started
[default: http] Command started
[default] synchronized from https://opam.ocaml.org

~/Documents/Work/Code/OCaml with graphics: opam upgrade
Already up-to-date.

~/Documents/Work/Code/OCaml with graphics: opam install graphics
The following actions will be performed:
  ∗  install graphics 1.0

=-=- Gathering sources =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=  ???? 

=-=- Processing actions -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=  ???? 
[graphics: ocamlc graphics.cma] Command started
[ERROR] The compilation of graphics failed at "ocamlc -custom graphics.cma -o
        test".

#=== ERROR while installing graphics.1.0 ======================================#
# opam-version         1.2.2
# os                   darwin
# command              ocamlc -custom graphics.cma -o test
# path                 /Users/Tim/.opam/system/build/graphics.1.0
# compiler             system (4.04.0)
# exit-code            2
# env-file             /Users/Tim/.opam/system/build/graphics.1.0/graphics-14648-7afd23.env
# stdout-file          /Users/Tim/.opam/system/build/graphics.1.0/graphics-14648-7afd23.out
# stderr-file          /Users/Tim/.opam/system/build/graphics.1.0/graphics-14648-7afd23.err
### stderr ###
# File "_none_", line 1:
# Error: Cannot find file graphics.cma

=-=- Error report -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=  ???? 
The following actions failed
  ∗  install graphics 1.0
No changes have been performed

=-=- graphics.1.0 troubleshooting -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=  ???? 
=> This package checks whether the Graphics library was compiled.

除了缺少图形包外，我的 ocaml 安装工作正常。

这里是 ~/.opam/system/build/graphics.1.0 中文件的内容

首先，graphics-14648-7afd23.err：

File "_none_", line 1:
Error: Cannot find file graphics.cma

然后是 graphics-14648-7afd23.info：

# opam-version         1.2.2
# os                   darwin
# command              ocamlc -custom graphics.cma -o test
# path                 /Users/Tim/.opam/system/build/graphics.1.0
# compiler             system (4.04.0)
# env-file             /Users/Tim/.opam/system/build/graphics.1.0/graphics-14648-7afd23.env
# stdout-file          /Users/Tim/.opam/system/build/graphics.1.0/graphics-14648-7afd23.out
# stderr-file          /Users/Tim/.opam/system/build/graphics.1.0/graphics-14648-7afd23.err

还有 graphics-14648-7afd23.env：

PATH=/Users/Tim/.opam/system/bin:/Library/Frameworks/Python.framework/Versions/3.2/bin:/opt/local/bin:/opt/local/sbin:/usr/bin:/bin:/usr/sbin:/sbin:/opt/local/bin:/usr/local/bin
OCAML_TOPLEVEL_PATH=/Users/Tim/.opam/system/lib/toplevel
PERL5LIB=/Users/Tim/.opam/system/lib/perl5:
MANPATH=/Users/Tim/.opam/system/man:/opt/local/share/man:
OPAMSWITCH=system
OPAMUTF8MSGS=1
CAML_LD_LIBRARY_PATH=/Users/Tim/.opam/system/lib/stublibs:/usr/local/lib/ocaml/stublibs
SHELL=/bin/bash
TERM=dumb
TMPDIR=/var/folders/kv/kmn525v16kb2mz2hrhq3q4mh0000gn/T/
BASHRC_HAS_BEEN_RUN=1
Apple_PubSub_Socket_Render=/private/tmp/com.apple.launchd.8tP8Ej926f/Render
EMACSDATA=/Applications/Emacs.app/Contents/Resources/etc
OLDPWD=/Users/Tim/Documents/Work/Code
EMACSPATH=/Applications/Emacs.app/Contents/MacOS/bin
USER=Tim
EMACS=t
SSH_AUTH_SOCK=/private/tmp/com.apple.launchd.EXKwsf0Dz0/Listeners
TERMCAP=
__CF_USER_TEXT_ENCODING=0x1F5:0x0:0x0
COLUMNS=190
BASH_PROFILE_HAS_BEEN_RUN=1
PWD=/Users/Tim/Documents/Work/Code/OCaml with graphics
XPC_FLAGS=0x0
XPC_SERVICE_NAME=0
EMACSLOADPATH=/Applications/Emacs.app/Contents/Resources/site-lisp:/Applications/Emacs.app/Contents/Resources/lisp:/Applications/Emacs.app/Contents/Resources/leim
SHLVL=1
HOME=/Users/Tim
LOGNAME=Tim
INFOPATH=/Applications/Emacs.app/Contents/Resources/info:
DISPLAY=/private/tmp/com.apple.launchd.jPYPDR7RIj/org.macosforge.xquartz:0
INSIDE_EMACS=23.1.1,comint
EMACSDOC=/Applications/Emacs.app/Contents/Resources/etc
_=/usr/local/bin/opam
OPAM_PACKAGE_VERSION=1.0
OPAM_PACKAGE_NAME=graphics
MAKELEVEL=
MAKEFLAGS=

最终文件 graphics-14648-7afd23.env 为空。

Answer 1

编辑：这个答案没有解决 OP 的问题。但我觉得这个答案还是有价值的，所以我把这个留在这里。

---

通过 OPAM 安装 OCaml 编译器，使用 opam switch <version number here>（可用版本号由 opam switch 显示）。 The graphics package 是一个用于检查the Graphics library 可用性的虚拟包，因此如果系统的OCaml 上没有库，opam install graphics 将失败。

您可以通过运行ls ~/.opam/*/lib/ocaml/graphics.cma 来确认图形库的存在。如果未找到文件，则未安装 Graphics，因此安装失败是有效行为。我不知道未安装 Graphics 的确切原因，但也许 Graphics 需要安装 X11 很重要。尤其是在 macOS 上安装 XQuartz 是很有必要的。有关详细信息，请参阅Shoe's answer。此外，之后还需要通过 OPAM 重新安装 OCaml。我们可以通过运行重新安装 OCaml：

opam switch reinstall <version number here>