From d3f1e04bd759b7c3f75c7f14a3d700c1ee87f799 Mon Sep 17 00:00:00 2001
From: Tony Garnock-Jones <tonygarnockjones@gmail.com>
Date: Mon, 13 Aug 2018 09:32:01 +0100
Subject: [PATCH] Tweak guard; small demo

---
 ansi/lcd-terminal.rkt     |  3 ++-
 ansi/test-screen-size.rkt | 24 ++++++++++++++++++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)
 create mode 100644 ansi/test-screen-size.rkt

diff --git a/ansi/lcd-terminal.rkt b/ansi/lcd-terminal.rkt
index 53dfeee..6442f09 100644
--- a/ansi/lcd-terminal.rkt
+++ b/ansi/lcd-terminal.rkt
@@ -126,7 +126,8 @@
     ["c" (S- 'right)]
     ["d" (S- 'left)]
     ["h" #:when (equal? params '(4)) (simple-key 'insert)] ;; st, http://st.suckless.org/
-    ["t" #:when (equal? (car params) 8) (apply screen-size-report (cdr params))]
+    ["t" #:when (and (= (length params) 3) (= (car params) 8))
+         (apply screen-size-report (cdr params))]
     [_ (simple-key (unknown-escape-sequence lexeme))]))
 
 (define (analyze-vt-O-mainchar lexeme mainchar)
diff --git a/ansi/test-screen-size.rkt b/ansi/test-screen-size.rkt
new file mode 100644
index 0000000..c925426
--- /dev/null
+++ b/ansi/test-screen-size.rkt
@@ -0,0 +1,24 @@
+#lang racket/base
+
+(require "main.rkt")
+
+(define (display* . things)
+  (for-each display things)
+  (flush-output))
+
+(define (main)
+  (tty-raw!)
+
+  (display* (dec-soft-terminal-reset)
+            (device-request-screen-size))
+
+  (define report (lex-lcd-input (current-input-port)))
+  (printf "The reported screen size is ~a columns and ~a rows.\r\n"
+          (screen-size-report-columns report)
+          (screen-size-report-rows report))
+  (printf "The raw report value itself is ~v.\r\n" report)
+
+  (display* (dec-soft-terminal-reset)))
+
+(module+ main
+  (main))