1 files changed, 62 insertions, 0 deletions

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+# utility functions for all shells
+# these should be POSIX-compatible.
+
+# add a path to PATH, but only if it's not already there
+path_add_to_PATH() { # path_add [-a] PATH...
+    # -a appends (default is prepend)
+    APPEND=false
+    if [ "x$1" = "x-a" ]; then
+        APPEND=true
+        shift
+    fi
+
+    for p; do
+        case ":$PATH:" in
+            *:"$p":*) ;;
+            *)
+                if $APPEND; then
+                    PATH="$PATH:$p"
+                else
+                    PATH="$p:$PATH"
+                fi
+                ;;
+        esac
+    done
+
+    unset APPEND
+}
+
+# Generalization of `path_add_to_PATH' for any variable.
+path_add_unsafe() { #path_add_unsafe [-a] [-d DELIM] VAR PATH...
+    ## Add PATH... to VAR, delimiting with DELIM (default :).
+    # By default, the VAR will be prepended to; passing -a will append the
+    # variable.  -d DELIM defines the delimiter.
+    #
+    # This function has the _unsafe suffix because it uses `eval' to set
+    # variables.
+    APPEND=false; DELIM=:
+    while getopts ad: opt; do
+        case "$opt" in
+            a) APPEND=true ;;
+            d) DELIM="$OPTARG" ;;
+            *) return 1 ;;
+        esac
+    done
+    shift $(expr $OPTIND - 1)
+
+    var="$1"; shift
+
+    for path; do
+        case ":$(eval "echo \$$var"):" in
+            *:"$path":*) ;;
+            *)
+                if $APPEND; then
+                    eval "$var=\$$var${var:+$DELIM}$path"
+                else
+                    eval "$var=$path${var:+$DELIM}\$$var"
+                fi
+                ;;
+        esac
+    done
+    unset -v APPEND DELIM var
+}