From 92073747bedbb2e8aabbb5154b5045400ce5ed33 Mon Sep 17 00:00:00 2001
From: Tom Ryder <tom@sanctum.geek.nz>
Date: Thu, 22 Dec 2016 12:39:11 +1300
Subject: Fork keep() to ksh

Mostly works.
---
 ISSUES.markdown      |   2 +
 ksh/kshrc.d/keep.ksh | 152 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 154 insertions(+)
 create mode 100644 ksh/kshrc.d/keep.ksh

diff --git a/ISSUES.markdown b/ISSUES.markdown
index 0949c0b6..db98183f 100644
--- a/ISSUES.markdown
+++ b/ISSUES.markdown
@@ -16,3 +16,5 @@ Known issues
 *   dr(1df) is probably more practical in awk
 *   How come commands I fix with the fc builtin always seem to exit 1 even if
     they succeed? Did I do that or is it Bash?
+*   mksh(1) when running keep() prints out variables with a "typeset" prefix
+    that seems to mask them when read back in
diff --git a/ksh/kshrc.d/keep.ksh b/ksh/kshrc.d/keep.ksh
new file mode 100644
index 00000000..90fd632f
--- /dev/null
+++ b/ksh/kshrc.d/keep.ksh
@@ -0,0 +1,152 @@
+#
+# keep -- Main function for kshkeep; provided with a list of NAMEs, whether
+# shell functions or variables, writes the current definition of each NAME to a
+# directory $KSHKEEP (defaults to ~/.kshkeep.d) with a .ksh suffix, each of
+# which is reloaded each time this file is called. This allows you to quickly
+# arrange to keep that useful shell function or variable you made inline on
+# subsequent logins.
+#
+# Consider a shell function declared inline with the NAME 'ayy':
+#
+#   $ ayy() { printf '%s\n' lmao ; }
+#   $ ayy
+#   lmao
+#   $ keep ayy
+#   $ keep
+#   ayy
+#   $ exit
+#
+# Then, on next login, the function is redefined for you:
+#
+#   $ ayy
+#   lmao
+#
+# To get rid of it:
+#
+#   $ keep -d ayy
+#
+function keep {
+
+    # Name self
+    typeset self
+    self=keep
+
+    # Figure out the directory to which we're reading and writing these scripts
+    typeset kshkeep
+    kshkeep=${KSHKEEP:-"$HOME"/.kshkeep.d}
+    mkdir -p -- "$kshkeep" || return
+
+    # Parse options
+    typeset opt delete
+    typeset OPTERR OPTIND OPTARG
+    while getopts 'dh' opt ; do
+        case $opt in
+
+            # -d given; means delete the keepfiles for the given names
+            d)
+                delete=1
+                ;;
+
+            # -h given; means show help
+            h)
+                cat <<EOF
+$self: Keep variables and functions in shell permanently by writing them to
+named scripts iterated on shell start, in \$KSHKEEP (defaults to
+~/.kshkeep.d).
+
+USAGE:
+  $self
+    List all the current kept variables and functions
+  $self NAME1 [NAME2 ...]
+    Write the current definition for the given NAMEs to keep files
+  $self -d NAME1 [NAME2 ...]
+    Delete the keep files for the given NAMEs
+  $self -h
+    Show this help
+
+EOF
+                return
+                ;;
+
+            # Unknown other option
+            \?)
+                printf 'ksh: %s -%s: invalid option\n' \
+                    "$self" "$opt" >&2
+                return 2
+                ;;
+        esac
+    done
+    shift "$((OPTIND-1))"
+
+    # If any arguments left, we must be either keeping or deleting
+    if (($#)) ; then
+
+        # Start keeping count of any errors
+        typeset -i errors
+        errors=0
+
+        # Iterate through the NAMEs given
+        typeset name
+        for name ; do
+
+            # Check NAMEs for validity
+            case $name in
+
+                # NAME must start with letters or an underscore, and contain no
+                # characters besides letters, numbers, or underscores
+                *[!a-zA-Z0-9_]*|[!a-zA-Z_]*)
+                    printf 'ksh: %s: %s not a valid NAME\n' \
+                        "$self" "$name" >&2
+                    ((errors++))
+                    ;;
+
+                # NAME is valid, proceed
+                *)
+
+                    # If -d was given, delete the keep files for the NAME
+                    if ((delete)) ; then
+                        rm -- "$kshkeep"/"$name".ksh ||
+                            ((errors++))
+
+                    # Save a function
+                    elif [[ $(whence -v "$name" 2>/dev/null) == *' is a function' ]] ; then
+                        typeset -f -- "$name" >"$kshkeep"/"$name".ksh ||
+                            ((errors++))
+
+                    # Save a variable
+                    elif [[ -n "$name" ]] ; then
+                        typeset -p -- "$name" >"$kshkeep"/"$name".ksh ||
+                            ((errors++))
+                    fi
+                    ;;
+            esac
+        done
+
+        # Return 1 if we accrued any errors, 0 otherwise
+        return "$((errors > 0))"
+    fi
+
+    # Deleting is an error, since we need at least one argument
+    if ((delete)) ; then
+        printf 'ksh: %s: must specify at least one NAME to delete\n' \
+            "$self" >&2
+        return 2
+    fi
+
+    # Otherwise the user must want us to print all the NAMEs kept
+    (
+        typeset keep
+        for keep in "$kshkeep"/*.ksh ; do
+            [[ -f "$keep" ]] || break
+            keep=${keep##*/}
+            keep=${keep%.ksh}
+            printf '%s\n' "$keep"
+        done
+    )
+}
+
+# Load any existing scripts in kshkeep
+for kshkeep in "${KSHKEEP:-"$HOME"/.kshkeep.d}"/*.ksh ; do
+    [[ -e $kshkeep ]] && source "$kshkeep"
+done
+unset -v kshkeep
-- 
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