add 'rvm export' and 'rvm unexport' actions.

these actions allow environment variables to be set per-project, by
setting them in the project rvmrc. unlike when using the 'export'
builtin, the changes to the environment are reverted when leaving
the environment or resetting rvm.

scripts/cli

@@ -35,7 +35,7 @@ __rvm_parse_args()
     if [[ $# -gt 0 ]] ; then next_token="$1" ; shift ; else next_token="" ; fi
 
     case "$rvm_token" in
-      fetch|version|srcdir|reset|debug|reload|update|monitor|notes|implode|seppuku|question|answer|env)
+      fetch|version|srcdir|reset|debug|reload|update|monitor|notes|implode|seppuku|question|answer|env|unexport)
         rvm_action=$rvm_token
       ;;
 
@@ -265,6 +265,18 @@ __rvm_parse_args()
         rvm_ruby_args="${rvm_token/%ss/s}"
       ;;
 
+      export)
+        if [[ ! -z "$next_token" ]] ; then
+          rvm_export_args="$next_token $@"
+          rvm_action="export"
+          rvm_parse_break=1
+
+        else
+          rvm_action="error"
+          rvm_error_message="rvm export must be followed by a NAME=VALUE argument"
+        fi
+      ;;
+
       -v|--version)
         if [[ -z "$next_token" ]] ; then
           rvm_action="version"
@@ -658,7 +670,7 @@ rvm()
 
   rvm_action="${rvm_action:-usage}"
 
-  export GEM_HOME GEM_PATH rvm_action rvm_archflags rvm_bin_flag rvm_bin_path rvm_clang_flag rvm_configure_flags rvm_debug_flag rvm_delete_flag rvm_docs_type rvm_dump_environment_flag rvm_error_message rvm_file_name rvm_gemdir_flag rvm_gemset_name rvm_head_flag rvm_install_arguments rvm_install_on_use_flag rvm_interactive_flag rvm_llvm_flag rvm_loaded_flag rvm_make_flags rvm_niceness rvm_only_path_flag rvm_parse_break rvm_patch_names rvm_patch_original_pwd rvm_pretty_print_flag rvm_prior_cc rvm_proxy rvm_quiet_flag rvm_ree_options rvm_reload_flag rvm_remove_flag rvm_ruby_alias rvm_ruby_aliases rvm_ruby_args rvm_ruby_file rvm_ruby_gem_home rvm_ruby_interpreter rvm_ruby_load_path rvm_ruby_make rvm_ruby_make_install rvm_ruby_patch_level rvm_ruby_repo_url rvm_ruby_repo_branch rvm_ruby_require rvm_ruby_string rvm_ruby_strings rvm_ruby_version rvm_script_name rvm_sdk rvm_silent_flag rvm_system_flag rvm_token rvm_trace_flag rvm_use_flag rvm_user_flag rvm_verbose_flag rvm_wrapper_name rvm_version rvm_static_flag
+  export GEM_HOME GEM_PATH rvm_action rvm_archflags rvm_bin_flag rvm_bin_path rvm_clang_flag rvm_configure_flags rvm_debug_flag rvm_delete_flag rvm_docs_type rvm_dump_environment_flag rvm_error_message rvm_file_name rvm_gemdir_flag rvm_gemset_name rvm_head_flag rvm_install_arguments rvm_install_on_use_flag rvm_interactive_flag rvm_llvm_flag rvm_loaded_flag rvm_make_flags rvm_niceness rvm_only_path_flag rvm_parse_break rvm_patch_names rvm_patch_original_pwd rvm_pretty_print_flag rvm_prior_cc rvm_proxy rvm_quiet_flag rvm_ree_options rvm_reload_flag rvm_remove_flag rvm_ruby_alias rvm_ruby_aliases rvm_ruby_args rvm_ruby_file rvm_ruby_gem_home rvm_ruby_interpreter rvm_ruby_load_path rvm_ruby_make rvm_ruby_make_install rvm_ruby_patch_level rvm_ruby_repo_url rvm_ruby_repo_branch rvm_ruby_require rvm_ruby_string rvm_ruby_strings rvm_ruby_version rvm_script_name rvm_sdk rvm_silent_flag rvm_system_flag rvm_token rvm_trace_flag rvm_use_flag rvm_user_flag rvm_verbose_flag rvm_wrapper_name rvm_version rvm_static_flag rvm_export_args
 
   case "$rvm_action" in
     use)             __rvm_use        ;;
@@ -760,6 +772,14 @@ rvm()
       fi
     ;;
 
+    export)
+      __rvm_export "$rvm_export_args"
+    ;;
+
+    unexport)
+      __rvm_unset_exports
+    ;;
+
     error) false ;;
 
     *)

scripts/utility

@@ -48,7 +48,7 @@ __rvm_teardown()
 
   fi
 
-  unset rvm_ruby_strings rvm_head_flag rvm_prior_cc next_token rvm_bin_path rvm_error_message rvm_gems_cache_path rvm_gems_path rvm_gemset_name rvm_interactive_flag rvm_man_path rvm_parse_break rvm_rc_files rvm_ruby_binary rvm_ruby_gem_home rvm_ruby_gem_path rvm_ruby_home rvm_ruby_interpreter rvm_ruby_irbrc rvm_ruby_log_path rvm_ruby_major_version rvm_ruby_minor_version rvm_ruby_package_name rvm_ruby_patch_level rvm_ruby_release_version rvm_ruby_repo_url rvm_ruby_repo_branch rvm_ruby_revision rvm_ruby_selected_flag rvm_ruby_tag rvm_ruby_version rvm_selfcontained rvm_token rvm_ruby_load_path rvm_path_flag rvm_ruby_require rvm_action rvm_ruby_package_file rvm_ruby_name rvm_static_flag
+  unset rvm_ruby_strings rvm_head_flag rvm_prior_cc next_token rvm_bin_path rvm_error_message rvm_gems_cache_path rvm_gems_path rvm_gemset_name rvm_interactive_flag rvm_man_path rvm_parse_break rvm_rc_files rvm_ruby_binary rvm_ruby_gem_home rvm_ruby_gem_path rvm_ruby_home rvm_ruby_interpreter rvm_ruby_irbrc rvm_ruby_log_path rvm_ruby_major_version rvm_ruby_minor_version rvm_ruby_package_name rvm_ruby_patch_level rvm_ruby_release_version rvm_ruby_repo_url rvm_ruby_repo_branch rvm_ruby_revision rvm_ruby_selected_flag rvm_ruby_tag rvm_ruby_version rvm_selfcontained rvm_token rvm_ruby_load_path rvm_path_flag rvm_ruby_require rvm_action rvm_ruby_package_file rvm_ruby_name rvm_static_flag rvm_export_args
 
   [[ ${rvm_dump_environment_flag:-0} -eq 1 ]] && __rvm_dump_environment
 
@@ -688,6 +688,8 @@ __rvm_reset()
 
   __rvm_unset_ruby_variables
 
+  __rvm_unset_exports
+
   configs=(system_ruby system_gem_path system_user_gem_path)
 
   for system_config in "${configs[@]}" ; do
@@ -1421,6 +1423,8 @@ __rvm_project_rvmrc()
 
         unset rvm_rvmrc_cwd rvm_previous_environment
 
+        __rvm_unset_exports
+
       fi
       break
     else
@@ -1438,6 +1442,8 @@ __rvm_project_rvmrc()
             rvm_previous_environment="$(__rvm_environment_identifier)"
 
             rvm_rvmrc_cwd="$cwd"
+
+            __rvm_unset_exports
 
             source "$cwd/.rvmrc"
 
@@ -1599,3 +1605,43 @@ __rvm_expand_ruby_string()
 
   return $?
 }
+
+__rvm_export()
+{
+
+  # extract the variable name from the first arg.
+  local name=${1%%=*}
+
+  # store the current value, to be restored later.
+  builtin export rvm_old_$name=${!name}
+
+  # pass-through the return value of the builtin.
+  export "$@"
+  return $?
+}
+
+__rvm_unset_exports()
+{
+  for pair in $(env); do
+
+    # ignore everything except for wrapped variables.
+    if [[ $pair =~ "rvm_old_" ]]; then
+
+      local wrap_name=${pair%%=*}
+      local name=${wrap_name#rvm_old_}
+      local value=${!wrap_name}
+
+      # if the old value is non-empty, restore it.
+      if [[ -n $value ]]; then
+        export $name=${value}
+
+      # otherwise, just remove it.
+      else
+        unset $name
+      fi
+
+      # unset the wrapped variable.
+      unset $wrap_name
+    fi
+  done
+}