(wip) semantic aliases

lib/scheme.class.js

@@ -22,6 +22,17 @@ function reverseHex(hex) {
   return `${m[3]}${m[2]}${m[1]}`;
 }
 
+// all other keys are assumed to be base00 colors or aliases
+RESERVED_KEYS = [
+  "scheme",
+  "author",
+]
+
+const MAX_ALIAS_DEPTH = 10
+const HEXCOLOR = /^([0-9A-F]){6}$/i
+class AmbiguousAlias extends Error {}
+class AliasRecursionOverflow extends Error {}
+
 /**
  * Represents a Base16 scheme definition.
  */
@@ -41,9 +52,29 @@ class Scheme {
    * for use with Base16 mustache templates.
    */
   parseScheme (data) {
+    const resolveAliases = (key, data) => {
+      let maxdepth = MAX_ALIAS_DEPTH;
+
+      let alias = data[key];
+      while (maxdepth--) {
+        if (!data[alias]) { return };
+
+        if (HEXCOLOR.test(alias)) {
+          let err = `Alias '${alias}' is ambiguous (could also be a hexcolor) and not allowed.`
+          throw new AmbiguousAlias(err);
+        }
+
+        data[key] = data[alias]
+        alias = data[alias]
+      }
+
+      throw new AliasRecursionOverflow(`Key ${key} led to alias recursion overflow.`)
+    }
     const hexDefinitions = Object.keys(data).reduce((accumulator, key) => {
+      resolveAliases(key, data);
+
       // we're only interested in the hex bases at this point
-      if (!/^base/i.test(key)) return accumulator
+      if (RESERVED_KEYS.includes(key)) return accumulator;
 
       const hex = data[key]
         // strip leading # if present for 0.10.0 spec