Amr Gharbeia
4e0b825fcc
draw-rect wrote \n after each row's fill, including the last row at the bottom of the frame. This caused a terminal scroll, shifting all content up by 1 and leaving the last row blank (terminal default bg). cursor-move-escape at the start of each iteration already repositions the cursor — the \n was never needed.
945 lines
34 KiB
Org Mode
945 lines
34 KiB
Org Mode
#+TITLE: Modern Backend
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#+STARTUP: content
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#+FILETAGS: :cl-tty:backend:
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* Overview
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The modern backend provides full-featured terminal rendering using raw
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escape sequences. It supports truecolor 24-bit color, OSC 8 hyperlinks,
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DECICM synchronized updates, SGR mouse tracking, kitty keyboard protocol,
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and Unicode box-drawing characters (single, double, rounded).
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All rendering functions produce CSI/OSC escape sequences directly --- no
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ncurses, no terminfo, no FFI. Color resolution handles named colors
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(~:red~, ~:blue~, etc.), hex strings (~"#FFD700"~), and semantic theme
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roles (~:accent~, ~:error~) via the ~*theme-colors*~ hash table.
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* Contract
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** Color and attribute helpers
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- ~(hex-to-rgb hex)~ (r g b) --- parse "#RRGGBB" or "#RGB"
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- ~(sgr-fg color)~ escape string --- foreground color escape
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- ~(sgr-bg color)~ escape string --- background color escape
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- ~(sgr-attr attr)~ escape string --- attribute escape (bold, italic, etc.)
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** Cursor helpers
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- ~(cursor-move-escape x y)~ escape string --- CSI cursor position
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- ~(cursor-style-escape shape blink)~ escape string --- DECSTR cursor shape
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** Sync and link helpers
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- ~(decicm-begin)~ escape string --- enable synchronized updates
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- ~(decicm-end)~ escape string --- disable synchronized updates
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- ~(osc8-link url text)~ escape string --- OSC 8 hyperlink wrapper
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** Border helpers
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- ~(border-char style pos)~ string --- Unicode box-drawing character
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** Modern backend class
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- ~(make-modern-backend &key output-stream)~ modern-backend
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- Implements all ~backend~ protocol methods with escape sequences
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* Tests
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The test suite lives in =modern-tests.lisp= and uses FiveAM. Each test
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covers one logical behavior.
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** Package and setup
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The test package uses =cl-tty.backend= to access internal symbols for
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white-box testing of escape generation.
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern-tests.lisp
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(defpackage :cl-tty-modern-backend-test
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(:use :cl :fiveam :cl-tty.backend)
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(:export #:run-tests))
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(in-package :cl-tty-modern-backend-test)
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#+END_SRC
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** Suite definition
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A single suite groups all modern backend tests.
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern-tests.lisp
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(def-suite modern-backend-suite :description "Modern backend tests")
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(in-suite modern-backend-suite)
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#+END_SRC
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** Test runner
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The =run-tests= entry point is called by the CI test harness.
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern-tests.lisp
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(defun run-tests ()
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(let ((result (run 'modern-backend-suite)))
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(fiveam:explain! result)
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(uiop:quit 0)))
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#+END_SRC
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** Constructor test
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Verifies that =make-modern-backend= returns an instance of the correct
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class. This is the most basic smoke test for the backend factory.
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern-tests.lisp
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(test make-modern-backend-creates
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"make-modern-backend returns a modern-backend instance"
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(let ((b (make-modern-backend)))
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(is (typep b 'cl-tty.backend::modern-backend))))
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#+END_SRC
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** SGR truecolor foreground escape
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Ensures a 6-digit hex string produces the correct 24-bit foreground
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escape sequence with red, green, and blue components in the right order.
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern-tests.lisp
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(test sgr-truecolor-foreground
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"SGR truecolor foreground escape is correct"
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(is (equal (cl-tty.backend::sgr-fg "#FFD700")
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(format nil "~C[38;2;255;215;0m" #\Esc))))
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#+END_SRC
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** SGR truecolor background escape
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Same as foreground but uses the =48= background prefix instead of =38=.
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern-tests.lisp
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(test sgr-truecolor-background
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"SGR truecolor background escape is correct"
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(is (equal (cl-tty.backend::sgr-bg "#1a1b26")
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(format nil "~C[48;2;26;27;38m" #\Esc))))
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#+END_SRC
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** SGR named color resolution
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Verifies that keyword symbols like =:red= and =:blue= resolve to the
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standard 8-color SGR codes (=31= foreground, =44= background).
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern-tests.lisp
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(test sgr-named-colors
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"SGR named colors resolve to 8-color codes"
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(is (equal (cl-tty.backend::sgr-fg :red)
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(format nil "~C[31m" #\Esc)))
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(is (equal (cl-tty.backend::sgr-bg :blue)
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(format nil "~C[44m" #\Esc))))
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#+END_SRC
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** SGR attribute escapes
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Each attribute keyword (=:bold=, =:italic=, =:underline=, =:reset=)
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should map to the correct SGR number.
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern-tests.lisp
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(test sgr-bold-italic
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"SGR attribute escapes are correct"
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(is (equal (cl-tty.backend::sgr-attr :bold) (format nil "~C[1m" #\Esc)))
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(is (equal (cl-tty.backend::sgr-attr :italic) (format nil "~C[3m" #\Esc)))
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(is (equal (cl-tty.backend::sgr-attr :underline) (format nil "~C[4m" #\Esc)))
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(is (equal (cl-tty.backend::sgr-attr :reset) (format nil "~C[0m" #\Esc))))
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#+END_SRC
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** Cursor move escape
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Verifies that =cursor-move-escape= produces a CSI =H= sequence with
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1-indexed row and column.
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern-tests.lisp
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(test cursor-move-escape
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"cursor-move generates correct CSI escape"
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(let ((b (make-modern-backend)))
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(is (equal (cl-tty.backend::cursor-move-escape 5 10)
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(format nil "~C[11;6H" #\Esc)))))
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#+END_SRC
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** Cursor style block
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Verifies the DECSTR escape for a block cursor without blinking (code 2).
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern-tests.lisp
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(test cursor-style-block
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"cursor-style :block generate correct escape"
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(let ((b (make-modern-backend)))
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(is (equal (cl-tty.backend::cursor-style-escape :block nil)
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(format nil "~C[2 q" #\Esc)))))
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#+END_SRC
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** Cursor style bar
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Verifies the DECSTR escape for a bar cursor without blinking (code 6).
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern-tests.lisp
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(test cursor-style-bar
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"cursor-style :bar generate correct escape"
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(let ((b (make-modern-backend)))
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(is (equal (cl-tty.backend::cursor-style-escape :bar nil)
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(format nil "~C[6 q" #\Esc)))))
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#+END_SRC
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** Cursor style underline with blink
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Verifies that =:underline= with =blink=t= produces code 5 (underline
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blinking), which is base 4 + blink offset 1.
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern-tests.lisp
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(test cursor-style-underline-blink
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"cursor-style :underline with blink"
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(let ((b (make-modern-backend)))
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(is (equal (cl-tty.backend::cursor-style-escape :underline t)
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(format nil "~C[5 q" #\Esc)))))
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#+END_SRC
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** DECICM synchronized update escapes
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Confirms that =decicm-begin= and =decicm-end= produce =?2026h= and
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=?2026l= respectively.
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern-tests.lisp
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(test decicm-escapes
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"DECICM synchronized update escapes"
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(is (equal (cl-tty.backend::decicm-begin) (format nil "~C[?2026h" #\Esc)))
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(is (equal (cl-tty.backend::decicm-end) (format nil "~C[?2026l" #\Esc))))
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#+END_SRC
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** OSC 8 hyperlink escape
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Verifies the full OSC 8 wrapping: opening sequence with URL, the text,
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and the closing sequence. The FORMAT string uses ~~ for literal tilde
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and ~\\ for literal backslash.
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern-tests.lisp
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(test osc8-escape
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"OSC 8 hyperlink escape wraps text"
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(is (equal (cl-tty.backend::osc8-link "http://example.com" "click here")
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(format nil "~C]8;;http://example.com~C\\click here~C]8;;~C\\"
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#\Esc #\Esc #\Esc #\Esc))))
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#+END_SRC
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** Hex color parsing (gold)
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Verifies that ="#FFD700"= parses to (255, 215, 0).
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern-tests.lisp
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(test hex-color-parsing
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"hex-to-rgb parses valid hex colors"
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(multiple-value-bind (r g b) (cl-tty.backend::hex-to-rgb "#FFD700")
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(is (= r 255))
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(is (= g 215))
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(is (= b 0))))
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#+END_SRC
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** Hex color parsing (black)
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Verifies all-zero parsing.
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern-tests.lisp
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(test hex-color-black
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"hex-to-rgb parses black"
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(multiple-value-bind (r g b) (cl-tty.backend::hex-to-rgb "#000000")
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(is (= r 0))
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(is (= g 0))
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(is (= b 0))))
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#+END_SRC
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** Hex color parsing (3-digit short form)
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Verifies that ="#F00"= expands to ="#FF0000"= = (255, 0, 0).
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern-tests.lisp
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(test hex-color-short-form
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"hex-to-rgb parses 3-digit hex"
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(multiple-value-bind (r g b) (cl-tty.backend::hex-to-rgb "#F00")
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(is (= r 255))
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(is (= g 0))
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(is (= b 0))))
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#+END_SRC
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** Border characters --- rounded style
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Confirms that =:rounded= style maps to the Unicode box-drawing
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characters for the four corners and edges.
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern-tests.lisp
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(test border-char-rounded
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"modern-border-char returns Unicode box-drawing for rounded style"
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(is (equal (cl-tty.backend::border-char :rounded :top-left) "╭"))
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(is (equal (cl-tty.backend::border-char :rounded :horizontal) "─"))
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(is (equal (cl-tty.backend::border-char :rounded :vertical) "│"))
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(is (equal (cl-tty.backend::border-char :rounded :bottom-right) "╯")))
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#+END_SRC
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** Border characters --- double style
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Confirms that =:double= style maps to double-line box-drawing characters.
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern-tests.lisp
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(test border-char-double
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"modern-border-char returns double-line chars"
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(is (equal (cl-tty.backend::border-char :double :top-left) "╔"))
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(is (equal (cl-tty.backend::border-char :double :horizontal) "═"))
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(is (equal (cl-tty.backend::border-char :double :vertical) "║")))
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#+END_SRC
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** Suspend/resume backend
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Verifies that suspend-backend and resume-backend are no-ops when called
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on a backend not attached to a real terminal (no errors, return nil).
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern-tests.lisp
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(test suspend-resume-noop
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"suspend-backend and resume-backend are no-ops in test context"
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(let ((b (make-modern-backend)))
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(is (null (multiple-value-list (suspend-backend b))))
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(is (null (multiple-value-list (resume-backend b))))))
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#+END_SRC
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* Implementation
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** Color and attribute helpers
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*** hex-to-rgb
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~hex-to-rgb~ parses hex color strings into (r g b) triplets. Handles
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both 6-digit (fully specified) and 3-digit (shorthand) formats. The
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3-digit form expands each hexit by duplicating it (=#F00= => =#FF0000=).
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
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(in-package :cl-tty.backend)
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(defun hex-to-rgb (hex)
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"Parse a hex color string like \"#FFD700\" into (values r g b).
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Also handles 3-digit hex like \"#F00\" (expands to \"#FF0000\")."
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(let ((clean (string-trim '(#\# #\Space) hex)))
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(if (= (length clean) 3)
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;; Expand 3-digit: #F00 -> #FF0000
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(let* ((r (parse-integer (subseq clean 0 1) :radix 16 :junk-allowed t))
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(g (parse-integer (subseq clean 1 2) :radix 16 :junk-allowed t))
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(b (parse-integer (subseq clean 2 3) :radix 16 :junk-allowed t)))
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(values (+ r (* r 16)) (+ g (* g 16)) (+ b (* b 16))))
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(values (parse-integer (subseq clean 0 2) :radix 16 :junk-allowed t)
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(parse-integer (subseq clean 2 4) :radix 16 :junk-allowed t)
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(parse-integer (subseq clean 4 6) :radix 16 :junk-allowed t)))))
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#+END_SRC
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*** *named-colors*
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Maps keyword color names to 8-color SGR index values. Used as the
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primary lookup in =sgr-fg= and =sgr-bg= before falling back to the
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theme colors hash table.
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
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(defparameter *named-colors*
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'((:black . 0) (:red . 1) (:green . 2) (:yellow . 3)
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(:blue . 4) (:magenta . 5) (:cyan . 6) (:white . 7)))
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#+END_SRC
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*** *theme-colors*
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Hash table mapping semantic theme role keywords to hex color strings.
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Populated by the theme system's =load-preset=. When a keyword is not in
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=*named-colors*=, =sgr-fg= and =sgr-bg= consult this table as a
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fallback, enabling user themes to define custom color roles.
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
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(defvar *theme-colors* (make-hash-table :test 'eq)
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"Hash table mapping theme keywords to hex color strings.
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Populated by the theme system's load-preset. Checked by sgr-fg/sgr-bg
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as a fallback when a keyword is not in *named-colors*.")
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#+END_SRC
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*** sgr-fg
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~sgr-fg~ produces the SGR foreground escape sequence. Resolution chain:
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hex string => named color => semantic theme role => empty string if
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unresolved. Truecolor uses =38;2;R;G;B=, named colors use =3n=.
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
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(defun sgr-fg (color)
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"Return SGR foreground escape for COLOR."
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(if (null color) ""
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(cond ((and (stringp color) (char= (char color 0) #\#))
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(multiple-value-bind (r g b) (hex-to-rgb color)
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(format nil "~C[38;2;~d;~d;~dm" #\Esc r g b)))
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((keywordp color)
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(let ((index (cdr (assoc color *named-colors*))))
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(if index
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(format nil "~C[~dm" #\Esc (+ 30 index))
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(let ((hex (gethash color *theme-colors*)))
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(if hex
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(multiple-value-bind (r g b) (hex-to-rgb hex)
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(format nil "~C[38;2;~d;~d;~dm" #\Esc r g b))
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"")))))
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(t ""))))
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#+END_SRC
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*** sgr-bg
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~sgr-bg~ produces the SGR background escape. Same resolution chain as
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=sgr-fg= but uses =48;2;R;G;B= for truecolor and =4n= for named colors.
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
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(defun sgr-bg (color)
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"Return SGR background escape for COLOR."
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(if (null color) ""
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(cond ((and (stringp color) (char= (char color 0) #\#))
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(multiple-value-bind (r g b) (hex-to-rgb color)
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(format nil "~C[48;2;~d;~d;~dm" #\Esc r g b)))
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((keywordp color)
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(let ((index (cdr (assoc color *named-colors*))))
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(if index
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(format nil "~C[~dm" #\Esc (+ 40 index))
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(let ((hex (gethash color *theme-colors*)))
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(if hex
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(multiple-value-bind (r g b) (hex-to-rgb hex)
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(format nil "~C[48;2;~d;~d;~dm" #\Esc r g b))
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"")))))
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(t ""))))
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#+END_SRC
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*** *sgr-attr-codes*
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Maps attribute keywords to SGR parameter numbers. Covers bold, dim,
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italic, underline, blink, reverse video, and reset.
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
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(defparameter *sgr-attr-codes*
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'((:bold . 1) (:dim . 2) (:italic . 3) (:underline . 4)
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(:blink . 5) (:reverse . 7) (:reset . 0)))
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#+END_SRC
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*** sgr-attr
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~sgr-attr~ looks up the keyword in =*sgr-attr-codes*= and produces the
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matching SGR escape.
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
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(defun sgr-attr (attr)
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"Return SGR attribute escape for ATTR keyword."
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(let ((code (cdr (assoc attr *sgr-attr-codes*))))
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(if code
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(format nil "~C[~dm" #\Esc code)
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"")))
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#+END_SRC
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** Cursor escapes
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*** cursor-move-escape
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Produces a CSI =H= (CUP) sequence to position the cursor. Coordinates
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are 1-indexed: =cursor-move-escape 0 0= moves to row 1, column 1.
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
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(defun cursor-move-escape (x y)
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"Return CSI escape to move cursor to (x, y), 1-indexed."
|
|
(format nil "~C[~d;~dH" #\Esc (1+ y) (1+ x)))
|
|
#+END_SRC
|
|
|
|
*** cursor-style-escape
|
|
|
|
Produces a DECSTR sequence (=CSI Ps q=) to set the cursor shape.
|
|
Base codes: block=2, underline=4, bar=6. When =blink= is true the code
|
|
is incremented by 1 (e.g. blinking block = code 3).
|
|
|
|
#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
|
|
(defun cursor-style-escape (shape blink)
|
|
"Return DECSTR escape for cursor shape."
|
|
(let* ((base (case shape
|
|
(:block 2) (:underline 4) (:bar 6)
|
|
(t 2)))
|
|
(code (if blink (1+ base) base)))
|
|
(format nil "~C[~d q" #\Esc code)))
|
|
#+END_SRC
|
|
|
|
** Sync and link escapes
|
|
|
|
*** decicm-begin
|
|
|
|
Enables DEC private mode 2026 (synchronized updates). All output
|
|
between =begin= and =end= is buffered by the terminal and rendered
|
|
atomically.
|
|
|
|
#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
|
|
(defun decicm-begin ()
|
|
"Return escape to enable synchronized updates."
|
|
(format nil "~C[?2026h" #\Esc))
|
|
#+END_SRC
|
|
|
|
*** decicm-end
|
|
|
|
Disables DEC private mode 2026, flushing the buffered frame to the
|
|
display.
|
|
|
|
#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
|
|
(defun decicm-end ()
|
|
"Return escape to disable synchronized updates."
|
|
(format nil "~C[?2026l" #\Esc))
|
|
#+END_SRC
|
|
|
|
*** osc8-link
|
|
|
|
Wraps text in an OSC 8 hyperlink. The opening sequence carries the URL,
|
|
the closing sequence (=ESC]8;;ESC\)=) terminates the link. This
|
|
allows clickable text in terminals that support the protocol.
|
|
|
|
#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
|
|
(defun osc8-link (url text)
|
|
"Wrap TEXT in an OSC 8 hyperlink to URL."
|
|
(format nil "~C]8;;~A~C\\~A~C]8;;~C\\"
|
|
#\Esc url #\Esc text #\Esc #\Esc))
|
|
#+END_SRC
|
|
|
|
** Border characters
|
|
|
|
*** *border-chars*
|
|
|
|
Lookup alist mapping =(style position)= pairs to Unicode box-drawing
|
|
characters. Covers single, double, and rounded styles with all four
|
|
corners plus horizontal and vertical connectors.
|
|
|
|
#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
|
|
(defparameter *border-chars*
|
|
'(((:single :top-left) . "┌") ((:single :top-right) . "┐")
|
|
((:single :bottom-left) . "└") ((:single :bottom-right) . "┘")
|
|
((:single :horizontal) . "─") ((:single :vertical) . "│")
|
|
((:double :top-left) . "╔") ((:double :top-right) . "╗")
|
|
((:double :bottom-left) . "╚") ((:double :bottom-right) . "╝")
|
|
((:double :horizontal) . "═") ((:double :vertical) . "║")
|
|
((:rounded :top-left) . "╭") ((:rounded :top-right) . "╮")
|
|
((:rounded :bottom-left) . "╰") ((:rounded :bottom-right) . "╯")
|
|
((:rounded :horizontal) . "─") ((:rounded :vertical) . "│")))
|
|
#+END_SRC
|
|
|
|
*** border-char
|
|
|
|
Looks up a border character by style and position. Falls back to
|
|
horizontal/vertical lines (=U+2500=, =U+2502=) if the style is unknown
|
|
for edge positions, or =+= for corners --- ensuring the UI never shows
|
|
a blank gap.
|
|
|
|
#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
|
|
(defun border-char (style pos)
|
|
"Return the Unicode box-drawing character for STYLE at POS."
|
|
(let ((char (cdr (assoc (list style pos) *border-chars* :test #'equal))))
|
|
(or char (if (member pos '(:horizontal :vertical))
|
|
(case pos (:horizontal "─") (:vertical "│"))
|
|
"+"))))
|
|
#+END_SRC
|
|
|
|
** Modern backend class
|
|
|
|
*** modern-backend (class)
|
|
|
|
Subclasses the abstract =backend= class. =output-stream= is where escape
|
|
sequences are written; =in-sync-p= tracks whether we are inside a
|
|
DECICM synchronized update block.
|
|
|
|
#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
|
|
(defclass modern-backend (backend)
|
|
((output-stream :initform *standard-output*
|
|
:initarg :output-stream
|
|
:accessor backend-output-stream)
|
|
(in-sync-p :initform nil :accessor in-sync-p)))
|
|
#+END_SRC
|
|
|
|
*** make-modern-backend
|
|
|
|
Factory function that creates a =modern-backend= instance. Accepts an
|
|
optional =output-stream=; defaults to =*standard-output*=. The
|
|
=color-palette= argument is ignored in favor of the dynamic
|
|
=*theme-colors*= hash table.
|
|
|
|
#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
|
|
(defun make-modern-backend (&key color-palette output-stream)
|
|
(declare (ignore color-palette))
|
|
(make-instance 'modern-backend :output-stream (or output-stream *standard-output*)))
|
|
#+END_SRC
|
|
|
|
** Lifecycle
|
|
|
|
*** initialize-backend
|
|
|
|
Enters the alternate screen buffer, enables mouse tracking (basic +
|
|
drag + SGR), bracketed paste mode, and the Kitty keyboard protocol.
|
|
Hides the cursor and flushes the stream. Returns the backend instance
|
|
for chaining.
|
|
|
|
#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
|
|
(defmethod initialize-backend ((b modern-backend))
|
|
(backend-write b (format nil "~C[?1049h" #\Esc)) ; alt screen
|
|
(backend-write b (format nil "~C[?1000h" #\Esc)) ; mouse basic
|
|
(backend-write b (format nil "~C[?1002h" #\Esc)) ; mouse drag
|
|
(backend-write b (format nil "~C[?1006h" #\Esc)) ; SGR mouse
|
|
(backend-write b (format nil "~C[?2004h" #\Esc)) ; bracketed paste
|
|
(backend-write b (format nil "~C[?u" #\Esc)) ; kitty keyboard
|
|
(cursor-hide b)
|
|
(finish-output (backend-output-stream b))
|
|
b)
|
|
#+END_SRC
|
|
|
|
*** shutdown-backend
|
|
|
|
Restores the terminal: shows the cursor, disables the Kitty keyboard
|
|
protocol, bracketed paste, SGR mouse, drag, basic mouse, and finally
|
|
leaves the alternate screen. Returns =nil= (via =(values)=).
|
|
|
|
#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
|
|
(defmethod shutdown-backend ((b modern-backend))
|
|
(cursor-show b)
|
|
(backend-write b (format nil "~C[?u" #\Esc))
|
|
(backend-write b (format nil "~C[?2004l" #\Esc))
|
|
(backend-write b (format nil "~C[?1006l" #\Esc))
|
|
(backend-write b (format nil "~C[?1002l" #\Esc))
|
|
(backend-write b (format nil "~C[?1000l" #\Esc))
|
|
(backend-write b (format nil "~C[?1049l" #\Esc)) ; normal screen
|
|
(finish-output (backend-output-stream b))
|
|
(values))
|
|
#+END_SRC
|
|
|
|
*** Suspend backend (temporary)
|
|
|
|
Temporarily suspends the modern backend, restoring the terminal to a
|
|
usable state so the shell (or parent process) can take over. Called
|
|
before =SIGTSTP= or similar process suspension.
|
|
|
|
Shows the cursor and exits the alternate screen buffer so the user
|
|
sees the normal terminal content. Does NOT disable mouse modes or
|
|
kitty keyboard — those would add ~100ms of overhead on every
|
|
suspend/resume cycle and are harmless while suspended (the terminal
|
|
just ignores the escape sequences).
|
|
|
|
#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
|
|
(defmethod suspend-backend ((b modern-backend))
|
|
(cursor-show b)
|
|
(backend-write b (format nil "~C[?1049l" #\Esc)) ; normal screen
|
|
(cursor-move b 0 0)
|
|
(finish-output (backend-output-stream b))
|
|
(values))
|
|
#+END_SRC
|
|
|
|
*** Resume backend (after suspend)
|
|
|
|
Re-initializes the modern backend after a suspension. Called after
|
|
=SIGCONT= or similar process resume.
|
|
|
|
Re-enters the alternate screen buffer and re-enables all input
|
|
features (mouse, bracketed paste, kitty keyboard). The application
|
|
is responsible for redrawing the full screen after resume.
|
|
|
|
#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
|
|
(defmethod resume-backend ((b modern-backend))
|
|
(backend-write b (format nil "~C[?1049h" #\Esc)) ; alt screen
|
|
(backend-write b (format nil "~C[?1000h" #\Esc)) ; mouse basic
|
|
(backend-write b (format nil "~C[?1002h" #\Esc)) ; mouse drag
|
|
(backend-write b (format nil "~C[?1006h" #\Esc)) ; SGR mouse
|
|
(backend-write b (format nil "~C[?2004h" #\Esc)) ; bracketed paste
|
|
(backend-write b (format nil "~C[?u" #\Esc)) ; kitty keyboard
|
|
(cursor-hide b)
|
|
(finish-output (backend-output-stream b))
|
|
(values))
|
|
#+END_SRC
|
|
|
|
** Backend-size via ioctl
|
|
|
|
*** backend-size
|
|
|
|
Uses ioctl (TIOCGWINSZ = 21523) to query actual terminal dimensions
|
|
from the kernel, with a ~/dev/tty~ fallback and 80x24 last resort.
|
|
|
|
#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
|
|
(defmethod backend-size ((b modern-backend))
|
|
;; Try ioctl on stdout, fall back to /dev/tty, then 80x24.
|
|
;; Each arm uses multiple-value-bind/values to preserve both cols and rows
|
|
;; (or discards secondary values, so we avoid it for multi-value returns).
|
|
(multiple-value-bind (cols rows)
|
|
(ignore-errors
|
|
(let* ((winsize (sb-alien:make-alien sb-alien:unsigned-short 4)))
|
|
(unwind-protect
|
|
(let ((ok (sb-unix:unix-ioctl
|
|
(sb-sys:fd-stream-fd (backend-output-stream b))
|
|
21523 (sb-alien:alien-sap winsize))))
|
|
(when ok
|
|
(values (sb-alien:deref winsize 1) ;; cols
|
|
(sb-alien:deref winsize 0)))) ;; rows
|
|
(sb-alien:free-alien winsize))))
|
|
(if (and cols rows (> cols 0) (> rows 0))
|
|
(values cols rows)
|
|
;; Direct ioctl on /dev/tty.
|
|
(multiple-value-bind (cols rows)
|
|
(ignore-errors
|
|
(let ((tty-fd (sb-unix:unix-open "/dev/tty" 0 0)))
|
|
(when (and tty-fd (numberp tty-fd) (> tty-fd 0))
|
|
(unwind-protect
|
|
(let* ((winsize (sb-alien:make-alien sb-alien:unsigned-short 4)))
|
|
(let ((ok (sb-unix:unix-ioctl tty-fd 21523
|
|
(sb-alien:alien-sap winsize))))
|
|
(when ok
|
|
(let ((cols (sb-alien:deref winsize 1))
|
|
(rows (sb-alien:deref winsize 0)))
|
|
(values cols rows)))))
|
|
(sb-unix:unix-close tty-fd)))))
|
|
(if (and cols rows (> cols 0) (> rows 0))
|
|
(values cols rows)
|
|
(values 80 24))))))
|
|
#+END_SRC
|
|
|
|
** Capability query and write
|
|
|
|
*** backend-write
|
|
|
|
Writes a string to the backend's output stream. Does NOT flush — the
|
|
caller is responsible for calling ~finish-output~ at appropriate sync
|
|
points (frame boundaries via ~end-sync~, initialization, shutdown).
|
|
Returns the string length for protocol compatibility.
|
|
|
|
#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
|
|
(defmethod backend-write ((b modern-backend) string)
|
|
(let ((stream (backend-output-stream b)))
|
|
(write-string string stream)
|
|
(length string)))
|
|
#+END_SRC
|
|
|
|
*** capable-p
|
|
|
|
Advertises which features this backend supports. =modern-backend=
|
|
supports truecolor, OSC 8 hyperlinks, DECICM sync, SGR mouse,
|
|
bracketed paste, cursor style control, and the Kitty keyboard protocol.
|
|
|
|
#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
|
|
(defmethod capable-p ((b modern-backend) feature)
|
|
(member feature '(:truecolor :osc8 :sync :mouse
|
|
:bracketed-paste :cursor-style
|
|
:kitty-keyboard)))
|
|
#+END_SRC
|
|
|
|
** Drawing
|
|
|
|
*** draw-text
|
|
|
|
Combines cursor positioning, SGR colors, optional attributes, the text
|
|
itself, and a reset into a single concatenated string. Minimizes output
|
|
calls --- one =backend-write= per draw operation --- by packing everything
|
|
into one buffer.
|
|
|
|
#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
|
|
(defmethod draw-text ((b modern-backend) x y string fg bg
|
|
&key bold italic underline reverse dim blink
|
|
&allow-other-keys)
|
|
(let ((parts (list (cursor-move-escape x y)
|
|
(sgr-fg fg) (sgr-bg bg)
|
|
(when bold (sgr-attr :bold))
|
|
(when italic (sgr-attr :italic))
|
|
(when underline (sgr-attr :underline))
|
|
(when reverse (sgr-attr :reverse))
|
|
(when dim (sgr-attr :dim))
|
|
(when blink (sgr-attr :blink))
|
|
string
|
|
(sgr-attr :reset))))
|
|
(backend-write b (apply #'concatenate 'string parts))))
|
|
#+END_SRC
|
|
|
|
*** draw-border
|
|
|
|
Builds the full border as three distinct string parts (top with optional
|
|
title, repeated mid sections, bottom) and writes them with minimal
|
|
output calls. The title can be left-aligned or centered within the top
|
|
border line. Uses the border character lookup for the chosen style.
|
|
|
|
#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
|
|
(defmethod draw-border ((b modern-backend) x y width height
|
|
&key style fg bg title title-align)
|
|
(let* ((s (or style :single))
|
|
(tl (border-char s :top-left))
|
|
(tr (border-char s :top-right))
|
|
(bl (border-char s :bottom-left))
|
|
(br (border-char s :bottom-right))
|
|
(h (border-char s :horizontal))
|
|
(v (border-char s :vertical))
|
|
(fg-esc (sgr-fg fg))
|
|
(bg-esc (sgr-bg bg))
|
|
(reset (sgr-attr :reset))
|
|
(inner-width (- width 2))
|
|
(hc (char h 0))
|
|
(top (if (and title (plusp (length title)))
|
|
(let* ((align (or title-align :left))
|
|
(max-tlen (- inner-width 2))
|
|
(tlen (min (length title) max-tlen))
|
|
(trunc-title (subseq title 0 tlen)))
|
|
(ecase align
|
|
(:left
|
|
(let ((right-hyphens (- inner-width tlen 2)))
|
|
(concatenate 'string
|
|
fg-esc bg-esc tl (string #\Space)
|
|
trunc-title (string #\Space)
|
|
(make-string (max 0 right-hyphens) :initial-element hc)
|
|
tr reset (string #\Newline))))
|
|
(:center
|
|
(let* ((total-pad (- inner-width tlen))
|
|
(left-pad (floor total-pad 2))
|
|
(right-pad (- total-pad left-pad)))
|
|
(concatenate 'string
|
|
fg-esc bg-esc tl
|
|
(make-string left-pad :initial-element hc)
|
|
trunc-title
|
|
(make-string right-pad :initial-element hc)
|
|
tr reset (string #\Newline))))))
|
|
(concatenate 'string
|
|
fg-esc bg-esc tl
|
|
(make-string inner-width :initial-element hc)
|
|
tr reset (string #\Newline))))
|
|
(mid (concatenate 'string
|
|
fg-esc bg-esc v
|
|
(make-string inner-width :initial-element #\Space)
|
|
v reset (string #\Newline)))
|
|
(bot (concatenate 'string
|
|
fg-esc bg-esc bl
|
|
(make-string inner-width :initial-element hc)
|
|
br reset)))
|
|
(backend-write b top)
|
|
(loop repeat (- height 2) do (backend-write b mid))
|
|
(backend-write b bot)))
|
|
#+END_SRC
|
|
|
|
*** draw-rect
|
|
|
|
Fills a rectangular area with a background color. For each row, moves
|
|
the cursor and writes a filled line. This is simpler than =draw-border=
|
|
because it has no border characters --- just spaces with a background
|
|
color.
|
|
|
|
#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
|
|
(defmethod draw-rect ((b modern-backend) x y width height &key bg)
|
|
(let* ((bg-esc (sgr-bg bg))
|
|
(reset (sgr-attr :reset))
|
|
(line (concatenate 'string
|
|
bg-esc
|
|
(make-string width :initial-element #\Space)
|
|
reset "")))
|
|
(loop :for row :from 0 :below height :do
|
|
(backend-write b (cursor-move-escape x (+ y row)))
|
|
(backend-write b line))))
|
|
#+END_SRC
|
|
|
|
*** draw-link
|
|
|
|
Draws a hyperlinked text at position (x, y). Combines cursor
|
|
positioning, optional fg/bg colors, the OSC 8 link wrapper around the
|
|
text, and a reset. This lets the user click the text to open the URL
|
|
in terminals that support OSC 8.
|
|
|
|
#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
|
|
(defmethod draw-link ((b modern-backend) x y string url
|
|
&key fg bg)
|
|
(let ((parts (list (cursor-move-escape x y)
|
|
(sgr-fg fg) (sgr-bg bg)
|
|
(osc8-link url string)
|
|
(sgr-attr :reset))))
|
|
(backend-write b (apply #'concatenate 'string parts))))
|
|
#+END_SRC
|
|
|
|
*** draw-ellipsis
|
|
|
|
Draws a three-dot ellipsis at the given position. The =width= parameter
|
|
is ignored since dots have a fixed visual length; delegates to
|
|
=draw-text= for uniform rendering.
|
|
|
|
#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
|
|
(defmethod draw-ellipsis ((b modern-backend) x y width
|
|
&key fg bg)
|
|
(declare (ignore width))
|
|
(let ((dots "..."))
|
|
(draw-text b x y dots fg bg)))
|
|
#+END_SRC
|
|
|
|
** Cursor and input methods
|
|
|
|
*** cursor-move
|
|
|
|
Delegates to =cursor-move-escape= and writes the resulting CSI sequence
|
|
to the output stream.
|
|
|
|
#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
|
|
(defmethod cursor-move ((b modern-backend) x y)
|
|
(backend-write b (cursor-move-escape x y)))
|
|
#+END_SRC
|
|
|
|
*** cursor-hide
|
|
|
|
Sends the DECTCEM private mode =?25l= to hide the cursor.
|
|
|
|
#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
|
|
(defmethod cursor-hide ((b modern-backend))
|
|
(backend-write b (format nil "~C[?25l" #\Esc)))
|
|
#+END_SRC
|
|
|
|
*** cursor-show
|
|
|
|
Sends =?25h= to restore the cursor visibility.
|
|
|
|
#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
|
|
(defmethod cursor-show ((b modern-backend))
|
|
(backend-write b (format nil "~C[?25h" #\Esc)))
|
|
#+END_SRC
|
|
|
|
*** cursor-style
|
|
|
|
Sets the cursor shape (block/underline/bar, optionally blinking) by
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delegating to =cursor-style-escape=.
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
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(defmethod cursor-style ((b modern-backend) shape &key blink)
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(backend-write b (cursor-style-escape shape blink)))
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#+END_SRC
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*** enable-mouse
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|
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Enables basic mouse tracking, button-event tracking (drag), and SGR
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|
extended mouse mode. These three modes together give full mouse
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|
support while staying compatible with modern terminal emulators.
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|
|
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#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
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(defmethod enable-mouse ((b modern-backend))
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(backend-write b (format nil "~C[?1000h" #\Esc))
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(backend-write b (format nil "~C[?1002h" #\Esc))
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|
(backend-write b (format nil "~C[?1006h" #\Esc))
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(finish-output (backend-output-stream b)))
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|
#+END_SRC
|
|
|
|
*** enable-bracketed-paste
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|
|
|
Enables bracketed paste mode, where the terminal wraps pasted text in
|
|
=ESC[200~= and =ESC[201~= delimiters. This allows the application to
|
|
distinguish user input from pasted content.
|
|
|
|
#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
|
|
(defmethod enable-bracketed-paste ((b modern-backend))
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|
(backend-write b (format nil "~C[?2004h" #\Esc))
|
|
(finish-output (backend-output-stream b)))
|
|
#+END_SRC
|
|
|
|
*** begin-sync
|
|
|
|
Begins a synchronized update frame using DECICM. Sets the =in-sync-p=
|
|
slot so other methods can check whether we are inside a sync block.
|
|
|
|
#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
|
|
(defmethod begin-sync ((b modern-backend))
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|
(setf (in-sync-p b) t)
|
|
(backend-write b (decicm-begin)))
|
|
#+END_SRC
|
|
|
|
*** end-sync
|
|
|
|
Ends the synchronized update frame and flushes the output, causing the
|
|
terminal to render the buffered changes atomically.
|
|
|
|
#+BEGIN_SRC lisp :tangle ~/.local/share/cl-tty/src/backend/modern.lisp
|
|
(defmethod end-sync ((b modern-backend))
|
|
(setf (in-sync-p b) nil)
|
|
(backend-write b (decicm-end))
|
|
(finish-output (backend-output-stream b)))
|
|
#+END_SRC
|