slosh.git/src/expr.h, branch master

slosh: defaults most people can live in, said by shaders

2026-08-19T11:46:57Z

The out-of-the-box look, rethought as one piece: - the compiled-in palette calms down: muted blue #7aa2f7 on the same neutral darks, with the colours that mean something kept semantic -- amber bell, red-orange dead. sl0p stays one include away as the house style, and contrib/themes/default.kdl is the starting point written down (theme-tour shows it). - derived state defaults now actually follow the theme: the scrolled wash is rebuilt from scroll_bg after the theme block (it used to bake the compiled accent), and declaring a state -- in any file of an include chain -- still wins. The dump writes derived states as comments so C-a e cannot pin what is meant to keep following. - a bell you can see: the frame blinks three times in theme's bell colour then breathes until answered, and a soft diagonal shimmer -- the bell colour halved towards default_fg, width breathing on a sine -- crosses the body for the same 900ms. bell_indicator false silences all of it; states { bell { } } replaces it like any state. since carries the clock dependency, so an idle session pays nothing. - scrollback says where it continues: while scrolled, the viewport's top and bottom rows melt towards an edge with content past it and turn solid at the buffer's end. New expression variables above/below (lines hidden past each edge, own dependency bit, cached per scroll position), carried in shade_ctx_t -- SLOSH_SHADER_ABI 3 -> 4. - expressions survive the dump: a program keeps its source and cb_chain writes it back, so amount="(y % 2) * 40" no longer dumps as a number. - headers move to include/, -Iinclude everywhere; the plugin Makefile's SLOSH var becomes SLOSH_DIR because slosh exports SLOSH=1 into every pane it runs, and building from inside a session read that as a path. - comment drift culled where features outran the prose, and the derivation boilerplate folded into derived_pass()/ctx_scroll().

slosh: rename the project from sl0ppty

2026-08-18T19:26:00Z

sl0p + pty was error-prone to type and the zero made it worse; slosh (slop + sh) is one syllable, impossible to typo, and slosh.foo is ours. Mechanical rename everywhere it appears: binary, env vars (SLOSH, SLOSH_SESSION, SLOSH_BIN, SLOSH_CONFIG), socket dir (/tmp/slosh-, $XDG_RUNTIME_DIR/slosh), config path (~/.config/slosh), header guards, src/sl0ppty.h -> src/slosh.h, contrib/sl0ppty-dev -> contrib/slosh-dev, the driving-slosh skill, docs and tests. The sl0ppi fork references and the sl0p theme stay: one is history, the other is the brand. The rename surfaced a latent bug in test_osc5577: the hello-reply answer always appeared on screen twice (ECHOCTL echo plus cat -v), but a seven-character implementation name happened to wrap the second copy across the 60-column boundary, so counting substrings in wrapped text found one and passed for the wrong reason. A five-character name moved the wrap and exposed it. The loop guard itself is correct -- with echo off before the request there is exactly one reply -- so the test now counts on de-wrapped text and tolerates the pane's own echo.

sl0ppty: shaders on the chrome, and two keys for the arrangement

2026-08-15T21:06:32Z

Five things, in one commit because they land in the same few files -- the action table, the shader pass, config.kdl -- and splitting them by hunk would buy a tidier log at the price of commits that do not build. Each is verified end to end; the suite is 46 files green. Chrome shaders. `where="chrome"` on any entry in `shaders` or in a `states` block runs that pass over a pane's frame -- border, padding, title, buttons -- instead of its contents. Nothing else changes: same registry, same `amount`, same expressions, same chain order, one new word, because a frame is another rect and so it is another pass. It runs over the frame's whole rect with the contents punched out as a hole, rather than four passes over four sides: an effect has to be able to travel round a border, and four passes would each count x/y from zero and restart at every corner. The hole keeps the two honest -- a skipped cell is never visited, so a full-strength chrome tint cannot reach your text. It is also the only kind of pass that can colour a pane a small window has collapsed to a single row (D6), which is the state where a colour is worth the most. `channel="fg"|"bg"|"both"` came out of looking at the first border flash: `tint` mixes both of a cell's colours, and a frame's background is the terminal's own default, so the pass materialised it to our guess at that default and mixed towards the colour -- a dark rectangle behind the glyphs, left there until the pane changed state. The mask is enforced by the pass, not the shader: the other colour is snapshotted before materialising and put back after, so an unset colour goes back to unset, it works for a built-in and a plugin alike, and no shader grows an fg-only twin of itself. A `bell` pane state and a `since` variable, because "flash the border when a pane rings" needed both and neither existed. `since` is milliseconds since the pane entered its current state, stamped in the one function that decides the state -- a transition is the one thing a frame cannot tell you, so it is remembered where it cannot disagree with the state it dates. `bell` ranks above the ambient states and below `dead`: a pane that rang while you were elsewhere is news, and a pane that rang and then exited is a pane that exited. It ends when you look at the pane, because that is what answering a bell is. Animation needed a clock and did not have one: a shader reading `t` only advanced when something else caused a frame, so a pulse froze the moment you stopped typing. `app_next_deadline_ms` now reports `anim_ms` while a chain that reads the clock ran over the last frame -- derived from what was applied, so a pulse hung off `dead` costs a clock while a pane is dead and nothing for the rest of the session. A `deadline` verb makes that observable; the server's poll loop already lived on the number. contrib/chrome has seven presets and the perimeter trick they are built on: on a frame the coordinate you want is distance along the ring, which the language can work out, and `min(d, P - d)` is what makes an effect cross the corner it started from. Hand-written, unlike contrib/shaders, because the toy previews contents and a frame has no preview to give -- so tests/test_chrome_presets.py checks each one the only way left: load it into a real session, assert the frame moves and the contents do not. `equalize` (C-a =) puts every share back to even: each split's children weighted by how many visible panes are behind them, so one pane beside a stack of three is a quarter of the width and "even" means the same thing at every depth. Exactly equal cell counts are not something a tree can always express, so the action promises the even division it can. `rotate-layout` (C-a Space) turns the whole tab a quarter turn clockwise. Every split changes axis and a row split's children reverse, because the pane on top of a stack is the pane on the right once you turn it; get that asymmetry wrong and you have a mirror image, which looks almost right until four turns fail to come back. They do come back, exactly, which is why the inverse is three more turns rather than a second mirrored routine with its own chance of being wrong -- and why a key as easy as space is the right one rather than a hazard. A turn is refused when it would not fit: a share of the height is not always a share the width can afford, and a node that cannot give its children their floor takes the whole tab down to a list. So the turn is tried, the layout is asked what it made of it, and one that flattened the tab is put back with a word. Same rule `split_fits` applies to splitting. Keys: the palette moves from `shift+p` to `p`, and cycling tabs from `n`/`p` to tab/shift+tab. `p` is pressed far more often than "the tab before this one" and was the only shifted letter in the defaults; tab is what every other tabbed thing cycles with, and `\e[Z` decodes as shift+tab on a plain terminal, so this costs nothing on a client without the kitty protocol. `n` is free again. The actions are untouched: two lines of config put the old binds back. The shader ABI goes to 3: `shade_ctx_t` gained `state_ms` and struct shader gained `channels`, both the pass's business rather than a shader's. Plugins need a rebuild, which is what the version is for.

sl0ppty: a shader's strength can be an expression

2026-08-14T20:39:18Z

Adding an effect meant writing C -- in the binary, or since D15 in a shared library. Both are a lot of ceremony for "dim every other row". So: `amount` may be an expression, compiled to bytecode when the config is read and evaluated per cell. shaders { dim amount="(y % 2) * 40" // scanlines dim amount="(x > cols - 10) * 120" // a right margin tint amount="255 - dist(x, y, curx, cury) * 12" color="#ff5fd7" } The scope is the argument, and that is the whole design. Every built-in here is already colour_op(amount) with the amount a pure function of position -- vignette, zebra, ruler, margin and spotlight differ only in that function -- so the part worth handing to a config is the *number*, not the colour maths. Three things follow at once: the mixing stays in C where it is fast and correct; an expression cannot produce an invalid cell, because it produces one byte; and that byte is cacheable. The cache is what makes an interpreter affordable, and the numbers are why this exists at all. Measured on a 200x50 pane, one pass: native vignette 6.1 ns/cell constant expression, folded 5.6 ns/cell positional expression, mapped 5.2 ns/cell animated (reads the clock) 35.0 ns/cell A shader you wrote in your config costs what a compiled one does. A program that does not read the clock is evaluated once per cell into a byte map and reused until something it reads changes; one that does read the clock is interpreted per cell, per frame, which is the honest price of animation and is opt-in. (The earlier measurement of 56ns for interpretation was per evaluation -- correct, and the reason the map exists rather than an argument against the language.) What a program reads is derived by the compiler rather than declared, and that dependency set *is* the cache key. A stale map is therefore unrepresentable rather than merely unlikely -- the same rule the layout follows, arrived at from the other direction. A unit test caught the first violation of it before anything else did: `cols` and `rows` carried no dependency flag, on the theory that the key always contains the rect, and so a program reading only the size looked constant and was folded at compile time, where every size is zero. The language is deliberately total. No loops, no recursion, no jumps: even `?:` compiles to evaluating both sides and selecting, because nothing in it has an effect. Evaluation is O(program length), so a config cannot spin, and there is nothing to sandbox. Division by zero is 0 rather than a trap: an expression that is wrong should look wrong, not take the session with it. One that does not compile drops that one shader with a warning -- not the config, and not the half-strength version of what you asked for, which is what the number path did with garbage and is now also fixed. shader_t gained the compiled program, so the plugin ABI goes to 2. A plugin built against 1 is refused with "shader ABI 1, we speak 2" and needs nothing but a rebuild -- the check earning its keep the first time it was asked to.