1 files changed, 58 insertions, 0 deletions
diff --git a/src/vars.sh b/src/vars.sh
new file mode 100644
index 0000000..d74506b
--- /dev/null
+++ b/src/vars.sh
@@ -0,0 +1,58 @@
+# Copyright (c) 2016 Egor Tensin <Egor.Tensin@gmail.com>
+# This file is part of the "Configuration file sharing" project.
+# For details, see https://github.com/egor-tensin/config-links.
+# Distributed under the MIT License.
+
+# Variable resolution
+
+declare -A cached_paths
+
+resolve_variable() {
+    if [ "$#" -ne 1 ]; then
+        echo "usage: ${FUNCNAME[0]} VAR_NAME" >&2
+        return 1
+    fi
+
+    local var_name="$1"
+
+    if [ -n "${cached_paths[$var_name]+x}" ]; then
+        echo "${cached_paths[$var_name]}"
+        return 0
+    fi
+
+    if [ "$var_name" = "$root_var_name" ]; then
+        echo ''
+        return 0
+    fi
+
+    if [ -z "${!var_name+x}" ]; then
+        dump "variable is not set: $var_name" >&2
+        return 1
+    fi
+
+    local var_path="${!var_name}"
+    traverse_path --exist --directory -- "$var_path"
+}
+
+cache_variable() {
+    local var_name
+    for var_name; do
+        [ -n "${cached_paths[$var_name]+x}" ] && continue
+        cached_paths[$var_name]="$( resolve_variable "$var_name" )"
+    done
+}
+
+readonly root_var_name='CONFIG_LINKS_ROOT'
+readonly var_name_regex='%\([_[:alpha:]][_[:alnum:]]*\)%'
+
+extract_variable_name() {
+    local s
+    for s; do
+        local var_name
+        if ! var_name="$( expr "$s" : "$var_name_regex/" )"; then
+            dump "couldn't extract variable name from: $s" >&2
+            return 1
+        fi
+        echo "$var_name"
+    done
+}