Add IO cleaning utilities

1 files changed, 32 insertions, 0 deletions

diff --git a/irc/clean.rkt b/irc/clean.rkt
new file mode 100644
index 0000000..09c2f93
--- /dev/null
+++ b/irc/clean.rkt
@@ -0,0 +1,32 @@
+#lang racket/base
+(require irc/command
+         racket/sequence racket/function racket/format)
+(provide (all-defined-out))
+
+(define (short-arg? v)
+  (or (string? v) (symbol? v) (number? v)))
+
+(define (ensure-all-short v)
+  (unless (andmap short-arg? v)
+    (error-user "You may only supply short (string, symbol, number) arguments")))
+
+(define (stringify v)
+  (cond [(string? v) (clean-control v)]
+        [(symbol? v) (clean-control (symbol->string v))]
+        [(number? v) (~a v)]
+        [else "<invalid>"]))
+
+(define (clean-control s)
+  (list->string
+    (sequence->list
+      (sequence-filter (negate char-iso-control?)
+                       (in-string s)))))
+
+; insert zero-width space to prevent clients from notifying a user
+(define (break-highlight s)
+  (if (zero? (string-length s))
+    s
+    (string-append
+      (substring s 0 1)
+      "\u200B"
+      (substring s 1))))