1 files changed, 81 insertions, 0 deletions
diff --git a/lib/functions.sh b/lib/functions.sh
new file mode 100644
index 0000000..f8e679f
--- /dev/null
+++ b/lib/functions.sh
@@ -0,0 +1,81 @@
+#!/bin/bash
+
+### ariketa helper functions
+
+# establish key bindings in current session
+## accepts split string arrays or strings, one array or string per binding
+_bindings.load_from_arrays () {
+    local _binding
+    for _binding; do
+        declare -n _binding_array="${_binding}"
+        bind "${_binding_array[*]}"
+    done
+}
+
+_example.highlight () { 
+    hl < <(echo "${_examples[$_I]}")
+}
+
+### prompt / tagging helpers
+
+#custom tag:value tuple handlers for _examples array
+## tag delineator is ":\n"
+_example.unpack() {
+    printf "%s" "${1#*:$'\n'}"
+}
+
+_tag.unpack() {
+    local _tag
+    printf -v _tag "%s" "${1%%:$'\n'*}"
+    (( ${#_tag} < ${#1} )) || return 1
+    printf "%s" "$_tag"
+}
+
+#presentation page header prompt display functions
+## specify custom indicator as argument, '+' is default
+_ps2.swap () {
+    local _cur_ps2="${PS2}"
+    PS2="$_old_ps2"
+    _old_ps2="$_cur_ps2"
+}
+
+_tag.same_as_next? () {
+    [[ "$(_tag.unpack "${_examples[$_I]}")" \
+    == "$(_tag.unpack "${_examples[$((_I+1))]}")" ]] \
+        || return 1
+    printf "%s" "${1:-+}"
+}
+
+_tag.same_as_prev? () {
+    [[ "$(_tag.unpack "${_examples[$_I]}")" \
+    == "$(_tag.unpack "${_examples[$((_I-1))]}")" ]] \
+        || return 1
+    printf "%s" "${1:-+}"
+}
+
+_tag.display () {
+    local _tag=$(_tag.unpack "${_examples[$_I]}") \
+        && printf "[$(_tag.same_as_prev?) %s $(_tag.same_as_next?)]" "${_tag}"
+}
+
+### public functions
+
+#simple bash code highlighting if the 'highlight' program is installed
+## http://www.andre-simon.de/doku/highlight/en/highlight.php
+hl () { 
+    local hl=$(which highlight 2>/dev/null) || {
+        printf "%s\n" "${@}"
+	return
+    }
+    "$hl" --syntax bash -O xterm256 "${@}"
+}
+
+#diff between adjacent examples
+ydiff () {
+    diff -wyW${COLUMNS:-80} \
+        <(echo "${_examples[(( _I - ${1:-1} ))]}") \
+        <(echo "${_examples[(( _I ))]}")
+    local diff_err=$?
+    (( diff_err <= 1 )) || return $diff_err
+    return 0
+}