add secret-values utility, to hide passwords

fixes https://github.com/ciel-lang/CIEL/issues/53

ciel.asd

@@ -101,6 +101,9 @@
                ;; string manipulation
                :str
 
+               ;; security
+               :secret-values
+
                ;;;
                ;;; Language extensions.
                ;;;

docs/dependencies.md

@@ -58,6 +58,7 @@ simple string literal definition that doesn't require escaping characters.
 - shasht: JSON reading and writing for the Kzinti.
 - shlex: Lexical analyzer for simple shell-like syntax.
 - spinneret: Common Lisp HTML5 generator.
+- secret-values: reduce the risk of accidentally revealing secret values such as passwords.
 - str: Modern, consistent and terse Common Lisp string manipulation library.
 - sxql: A SQL generator
 - trivia: NON-optimized pattern matcher compatible with OPTIMA, with extensible optimizer interface and clean codebase

docs/libraries.md

@@ -782,6 +782,29 @@ Use `ppcre`.
 
 See <https://common-lisp-libraries.readthedocs.io/cl-ppcre> and <https://lispcookbook.github.io/cl-cookbook/regexp.html>
 
+## Security
+
+We ship [secret-values](https://github.com/rotatef/secret-values) that
+helps in reducing the risk of accidentally revealing secret values,
+such as passwords.
+
+When you read a password, you can hide it behind a `secret-values` object:
+
+```lisp
+(secret-values:conceal-value "secret")
+;; => #<SECRET-VALUES:SECRET-VALUE {100F2EC9E3}>
+```
+
+To reveal it, at the last moment, use:
+
+```lisp
+(secret-value:reveal-value *)
+;; => "secret"
+```
+
+See also what `ensure-value-revealed` does on their documentation.
+
+
 ## Threads, monitoring, scheduling
 
 We ship: