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sva_cli/
help.rs

1// Concern: the `--help` page, each flag's default printed from its own constant | Non-concern: parsing those flags (args/), the JSON a subcommand answers (output.rs) | IO: () -> the page
2
3use sva_core::DEFAULT_STORE_BYTES;
4use sva_core::solve;
5use sva_engine::resample;
6use sva_engine::{
7    DEFAULT_BAND_FLOOR_DB, DEFAULT_BUFFER_SECS, DEFAULT_CELL_SECS, DEFAULT_FLOOR_DB,
8    DEFAULT_FRAME_SECS, DEFAULT_LEDGER_DEPTH, DEFAULT_MAX_PAIRS, DEFAULT_MAX_PEAKS,
9    DEFAULT_MODULATION_WINDOW_SECS, DEFAULT_NOVELTY_WINDOW_SECS, DEFAULT_OVERSAMPLE,
10    DEFAULT_PERIODICITY_WINDOW_SECS, DEFAULT_PRUNE_DB, DEFAULT_SAMPLE_RATE, DEFAULT_SMOOTH_SECS,
11    PSYCHOACOUSTIC_V1, READINGS, Reads, self_similarity::MAX_CELLS, spectrum,
12};
13
14/// Read off the constants the parser itself defaults to, so a printed default cannot drift
15/// from the one a render actually uses.
16pub fn help_text() -> String {
17    let bits = PSYCHOACOUSTIC_V1.precision_bits;
18    let store_gb = DEFAULT_STORE_BYTES >> 30;
19    let representations = representations();
20    let (min_frame, max_frame) = (spectrum::MIN_FRAME, spectrum::MAX_FRAME);
21    let rules = solve_rules();
22    let floor = solve::FLOOR_DB;
23    let (max_renders, step_tol, cost_tol) = (
24        solve::DEFAULT_MAX_RENDERS,
25        solve::DEFAULT_STEP_TOL,
26        solve::DEFAULT_COST_TOL,
27    );
28    let (passband, stopband) = (resample::PASSBAND, resample::STOPBAND);
29    let bound = format!("{} dB", 20.0 * resample::BOUND.log10());
30    format!(
31        r#"USAGE:
32  sva-cli (render | analyze | solve | lint | trace | builtins | outline | new) [arguments]
33
34DESCRIPTION:
35  A composition is a directory of node files, each one closed-form expression in
36  `t` or `f` on one line, or a score placing notes in time. sva-cli reads that
37  composition and prints what it is and what it sounds like, as JSON on stdout.
38  `render`, `solve`, `lint` and `trace` read the current directory; `new` writes
39  beside it and `analyze` reads a file. `solve` fits variables to a reference.
40
41SCORES:
42  A score is a `.jsonl` file: JSON Lines, one object per line, sorted by `at`;
43  `@score/drop` reads `score/drop.jsonl`, and a ref never writes `.jsonl`. A
44  file with no extension opening with `{{` refuses with the rename. Line 1 is
45  its annotation, the doc comment's four fields, which `lint` holds it to:
46    {{"annotation": "Models: ... | Neglects: ... | IO: (t) -> amplitude | Tags: ..."}}
47  Every other line is one kind, told by its keys, and may add `"comment"`:
48    event    "at", "node", "deg", "len" and the node's parameters: plays it
49    mark     "at", "mark": a point `mark(name)` reads in this file's times
50    comment  "at", "comment": a note to the reader at a time
51    move     "at", "lane", "to", and "node", "len", "shape" where written
52  A score lowers to equations, the sum of its events in written order, each
53  its node shifted to its `at`; marks, comments and moves sound nothing.
54    at     a time string, "0.25b" or "0.5s", or arithmetic over times, "2b +
55           1b/3" for a triplet; a bare number has no unit and refuses. A file
56           counts every time in bars or every one in seconds. "mark(verse) -
57           2b" is a position, "mark(drop) - mark(build)" a duration.
58    node   an `@ref` from the score's own directory: a sound, an equation or
59           another score. On a line placing a score `len` crops it there and
60           nothing else binds; a `node` list mixing scores and sounds refuses
61           `len`.
62    deg    a whole scale degree counted from 1, the tonic: sugar for "f0":
63           "deg(n)". In a seven-row scale 8 is the tonic an octave up, 0 the
64           seventh below and -6 the tonic an octave down. A chromatic note
65           binds "f0": "deg(7)*1st"; a line writing both refuses.
66    len    a time as `at` takes, bound as the node's `len`.
67    other  binds the node's parameter of that name: a number, or a constant in
68           a string, "0.03s", "-6db", "900hz", "A1", "0.8*0.9", "deg(5)/2".
69  Any field but `comment` may be a list. A line listing N items is N events,
70  moves or marks, item i of every list going to the i-th and a single value to
71  all; lists of different lengths refuse. A chord is a `deg` list on one `at`:
72    {{"at": "0b", "node": "@../instruments/keys", "deg": [1, 3, 5],
73      "vel": [0.8, 0.5, 0.6]}}
74  `deg(n)` is the tonic in `variables/key` times degree n's ratio in the scale
75  `variables/scale` names, read where the line sits, in a score or in any
76  equation. A scale is one the language names, as `minor` or `dorian` (`sva-cli
77  builtins` lists each with its cents), or a file of one row per degree in cents
78  above the tonic, ascending, the last the period, named by a ref: a file
79  `scales/custom` holding 200 400 500 700 900 1100 1200 is the major scale. A
80  value reading `t` or a `@ref`, a field the node does not read, a parameter it
81  reads that nothing binds, and a `deg` with no scale refuse before any audio,
82  each naming the score's file, line and column.
83
84  A lane is one value moving through the song: a node's parameter, a move
85  naming "node" and "lane": "cutoff", or a variable under `variables/`, a move
86  naming "lane" alone: "energy", "key", "scale", "bpm" (never "meter"). A move
87  with no `len` sets the lane at `at`; with "len" and "shape", `lin` or `exp`,
88  it ramps there from the value it holds:
89    {{"at": "24b", "node": "@../instruments/saw", "lane": "cutoff",
90      "to": "9khz", "len": "8b", "shape": "exp"}}
91    {{"at": "72b", "lane": "key", "to": "key*2st", "comment": "a tone up"}}
92    {{"at": "92b", "lane": "bpm", "to": "bpm*8/9", "len": "4b", "shape": "lin"}}
93  A `to` naming the lane means its home value, the node's default or the
94  variable's file, so it follows `--set`. A lane reaches every instance of its
95  node, from a score or an equation, inside a wrapper too, unless the line or
96  an invoking equation passes that parameter, which wins. Where it holds one
97  value over an instance's span it binds that number; where it moves there the
98  instance reads it at its song time, and where the engine refuses a moving
99  value, such as `sat`'s `drive`, the move refuses as `bad-lane`: pass a
100  constant, move the lane between notes, or close the sound's tail with a crop.
101  A score's times ride the tempo curve the `bpm` lane draws; `b` in an equation
102  stays a bar of `variables/bpm`. A song places its sections at marks:
103    {{"at": "0b", "mark": "intro"}}
104    {{"at": "mark(intro)", "node": "@intro"}}
105    {{"at": "mark(intro) + 8b", "mark": "verse"}}
106    {{"at": "mark(verse)", "node": "@verse"}}
107  `concat` and `repeat` place parts on the curve too: `repeat(@score/riff-1b, 4)`.
108  An equation reading a score at `t - d`, an echo or a send, hears the song as
109  it was d earlier: its lines keep their song time, and a move however many
110  reads reach it is one move.
111  A control score is one no sounding score places, read by an equation as a
112  signal: `@score/song(t) * (1 - @score/pump(t))` ducks the song under it.
113  `sva-cli outline @score/song` prints a song's marks, tempo, lanes, events and
114  size. Lint and render warn of a line passing a parameter whose lane ramps
115  under it (`line-overrides-lane`), and of a lane no instance reads
116  (`lane-reaches-nothing`).
117
118RESERVED VARIABLES:
119  Four nodes under `variables/` are reserved: a ref reads one like any node,
120  and a bar or a degree reads one by name:
121    variables/bpm     a number, the beats per minute: 120
122    variables/meter   beats per bar over the note: 4/4
123    variables/key     the tonic `deg` counts from, a note or hertz: C3
124    variables/scale   the scale `deg` counts in, a built-in's name: major, or a
125                      ref to a scale file: @../scales/custom
126  A `b` literal or a file's `-2b` span reads bpm and meter; a `deg(n)` reads key
127  and scale. Before anything renders, each read is replaced by its value, by one
128  pass for all four: a bar becomes `n*(beats*60/bpm)` seconds and `deg(n)`
129  becomes `@variables/key` times degree n's ratio, the tonic still a ref. A
130  read with no value to replace it refuses as `bad-tempo` or `bad-scale`, as
131  does a variable holding no such value, such as bpm without meter, or a
132  scale name no built-in has, which refuses listing every built-in. A stream's
133  edit to a variable, or to the scale file it names, replaces every read of it
134  again. A node elsewhere named `bpm` is an ordinary node. Any other file under
135  `variables/`, as `variables/energy` holding 0.5, is a variable of the
136  composition's own: a ref reads it, `--set` sets it, and a score's moves move
137  it, as they move the reserved ones but `meter` (SCORES).
138
139RENDER:
140  sva-cli render '<expression>' --representation <list> [--until '<condition>']
141                 [--bits <n>] [--rate <hz>] [--threads <n>] [--cache <path|none>]
142                 [--set <name>=<text>]... [--confirm]
143
144  Renders one expression, in the grammar a node file's body uses, and prints one
145  reading per representation under `data.representations`. `@path` reads a node
146  from the current directory and `@/abs/path` one anywhere; there is no default
147  target. Every reading states its `source` (exact or measured), the
148  conformance profile it ran under, and its rate.
149
150  The target's own ref may read an interval: `@piano4([0, 2b], f0=C4,
151  vel=0.5, release=1s)`, where `release` is the instrument's own parameter. Its ends are the language's literals (`s`, `ms`, `b`,
152  `sp`, or a bare `0`); `[a, inf)` and `[a,)` leave the end open; the other
153  arguments are the node's own named ones. The start trims the output alone:
154  history before it is still computed, so a loop or a filter carries the state
155  it had there. With no interval the render starts at 0, earlier only where a
156  crop reaches before it, and its end is open. Inside an expression a window is
157  a `crop`. A target that samples its one ref read, `sample(@piano4([0, 2b],
158  f0=C4))`, reads that ref's interval and binds and the same node values.
159
160  `sample("<path>")` is a recording: a `.wav` file, relative to the directory
161  sva-cli runs in or absolute; keep it outside the composition, where it would
162  be read as a node. It is the file's samples at the render's rate, one
163  component per channel as `join` makes them, silent outside the file's span. At
164  its own rate every sample passes unchanged. At another a cos^16-windowed sinc
165  reads it: a tone up to {passband} of the lower rate reads within {bound} of
166  itself, and one from {stopband} of it at most {bound} of its level, a bound
167  proven for the kernel that the label states under `resampled` beside the rate
168  it came from. The path is the language's one string, in double quotes and
169  only as `sample`'s one argument; one naming no file refuses as `not_found`. A
170  store keys a recording by its samples and rate, never its path.
171
172  Every node is computed over its support met with what reads it, and nowhere
173  else: outside its support a node is exactly zero. A closed interval renders
174  exactly its length, nothing cut. An open one ends where the root's support
175  does: a crop's end, the exact underflow of an `exp`, a clamp holding a factor
176  at zero; or earlier, where a proven upper bound on the root's magnitude stays
177  under the profile's silence threshold (-120 dBFS) from a sample on. A root
178  with no such bound (a held sine, a loop) is never cut. The label's `pruned`
179  states the threshold as `db` and the root's cut, `from` the sample the render
180  is treated as silent from. A stream's term leaves `@notes` where its support
181  ends. An open interval over a root whose support never ends and is never cut
182  (a held sine, a physical solver) refuses as `render.no_end`. A short-time
183  transform reads its input whole, and refuses one with no end as
184  `engine.unbounded_extent`. A form in `f` with no dual in `t` has no samples
185  and refuses as its dual does, `cast.left_algebra`.
186
187  A render is a stream pulled to its end: a closed form, a short-time
188  transform and what either reads are computed over their whole extent first,
189  and every other node block by block. `--until '<condition>'` stops the render
190  at the first sample the condition holds at, or at the interval's end,
191  whichever is first. It is checked as each block is pulled, so no node driven
192  block by block runs past the block it holds in. A condition compares (`<`,
193  `<=`, `>`, `>=`) `t`, `envelope(t)` (the RMS over every channel of the
194  `envelope` representation's frame holding `t`, framed by its own `frame`
195  where one is asked) and literals, joined by `and`/`or`.
196
197  `--representation <list>` takes a comma list of readings and may repeat. Each
198  is a call in the language's own syntax, its options its named arguments:
199  `spectrum(peaks=8, frame=50ms)`, `ledger(depth=3, brief=1)`. A `frame`,
200  `window`, `cell` or `smooth` is a time as a score writes one, in seconds,
201  `50ms`, or in bars, `1b/8` (`1/8b` is one over eight bars), a bar lasting
202  what the render's tempo says; where none is known, as in `analyze`, bars
203  refuse as `tempo.invalid_bpm_meter`. An entry
204  followed by `=<path>` writes a file instead, listed under `written`:
205  `samples=<path>.wav` writes audio, encoded as `--bits` says; any other path
206  takes the reading's JSON, uncapped. A path that already holds a file refuses
207  unless `--confirm` is written. `samples=alsa:<device>` plays the samples on
208  that ALSA device (`alsa:default`, `alsa:hw:1`, `alsa:plughw:1,0`) as each
209  block is pulled, in real time, through `aplay` from alsa-utils; Linux only,
210  anywhere else it refuses as `destination.unsupported_platform`. It sends
211  32-bit floats, or integer PCM where `--bits` is 16 or under. A device that
212  cannot take the format refuses with aplay's reason, and one aplay says plays
213  another rate than the render's stops there as `destination.rate_inexact`.
214  `samples(buffer=<t>)` is how much the device holds ahead of what it plays.
215  Once it has played out, `data.played` states the device, its seconds, rate,
216  channels, format, the buffer asked and the one granted, and every underrun
217  aplay reported, with what it cannot see.
218  `lines`, `atoms`, `derivative`, `bindings`, `arguments`, and a closed form's
219  `spectrum`, `envelope` and `pitch`, read the expression and ignore the range.
220
221  A closed form's `spectrum` and `pitch` are its exact lines, so a term under a
222  crop or an envelope, which has a width and is no line, refuses them; so do
223  `spectrum(frame=)` and `envelope(frame=)`, as a closed form has no frames. To
224  measure any of them frame by frame, a reader samples the target's ref,
225  `sample(@x([0, 1s]))`, and an author writes `sample(...)` inside the node.
226  A closed form with no exact envelope, such as a crop of a decay, refuses
227  `envelope` with the reason rather than measuring it unasked; `sample(...)`
228  asks for the measured one. A measured `spectrum` is one spectrum: whole
229  windows across the range, averaged, the first at its first sample and the last
230  ending at its last, evenly at most half a window apart; a window is `frame`
231  rounded up to a power of two samples, at least {min_frame}, or without `frame`
232  the range's length so rounded, at most {max_frame}. `pitch` is framed, one entry
233  per `frame`; for the spectrum at one instant, read a range one frame long.
234  A measured `envelope` is framed too, and reads every channel: a frame's
235  `rms` is the root mean square of all its channels' samples together, its
236  `peak` the largest magnitude in any channel. `onsets` reads every channel
237  as well: a frame's flux is the sum of each channel's, and a strike's energy
238  that of all channels' samples together, so opposite phases cancel nothing.
239  Every other measured reading but `stereo` reads every channel in power, as
240  `envelope` reads a level: a spectrum's power per bin (`spectrum`, `pitch`,
241  the partials `dissonance`, `voice_leading`, `tonal_distance`,
242  `inharmonicity` and `self_similarity` pick), a formant frame's
243  autocorrelation and each auditory band's energy (`bands`, `periodicity`,
244  `modulation`, `self_similarity`) are each channel's averaged, so a channel
245  copied to two reads as itself; `crest` sets any channel's peak against the
246  RMS of all of them together. A closed form's exact readings read every
247  channel in power too: a partial's squared amplitude (`pitch`, `dissonance`,
248  `voice_leading`, `tonal_distance`, `inharmonicity`) is summed over the
249  channels at its frequency and divided by their count, and a spectrum of more
250  than one channel lists each frequency once, its amplitude the root of that
251  mean power, real, as channels share no phase.
252
253  `--bits <n>` is the precision every sample is written to, from 2 to 52: the
254  point where a series is truncated, and the encoding of a `.wav`, integer PCM
255  at n bits up to 16 and 32-bit float above. `--rate <hz>` (default
256  {DEFAULT_SAMPLE_RATE}) is the one rate a render samples at: the target is read
257  at its instants, and every node at the instants its reader asks for. A
258  closed form is exact at any instant, and so is a continuous loop, one
259  constant delay at a gain under 1 over a closed form such as
260  `x + 0.5*self(t - 17ms)`, which is its series. A filter, a discrete loop, a
261  solver and `rand` step at the rate asked for, where `1sp` is one step, so an
262  `sp` count or `self[idx(t) - 1]` means one sample at whatever rate is asked.
263  `rand` draws once per step, keyed by that step's index; a key between steps
264  reads the step nearest it, ties to even.
265
266  `--set <name>=<text>` renders as if the variable `variables/<name>` held
267  `<text>`, and writes no file: `--set key=G3` transposes every degree to G3,
268  `--set scale=dorian` changes mode (a scale file is a ref written from
269  `variables/`, as the file holds it: `--set scale=@../scales/custom`), `--set
270  bpm=140` moves every bar, `--set meter=3/4` regroups them and `--set
271  energy=0.8` sets a variable of the composition's own. It sets a lane's home
272  value: a move whose `to` names it follows. It may repeat, once per variable: a
273  variable set twice refuses as `render.set_twice`, a name with no file under
274  `variables/` that is no reserved one as `render.set_unreserved`, listing the
275  variables there, and the file's path, `variables/key=G3`, as
276  `render.set_path`, naming the short form.
277
278  `--threads <n>` (default: every core the machine reports) is the most
279  threads a render computes on; `1` computes every value in turn on one.
280  Values none of the others reads, and the blocks of a value that holds no
281  state, compute apart, to the same bits on any number of threads.
282
283  A discrete loop reads its own past only by index; `self(t - d)` in one
284  refuses as `type.discrete_self_at_time`, naming what made it discrete. A
285  read `@x(k*t - d)` steps `x` at `k` times the step, every input it reads,
286  `sp` and `idx` with it, and rounds `d` to the nearest sample of that step,
287  ties to even: shifts are rounded to the nearest sample so placements share
288  one cached value; timing is exact to half a sample, and the label's
289  `moved_s` states the most any read moved. A node is computed once
290  per step however many reads ask for it. A node that holds state read at a
291  time that moves refuses as `type.stateful_warp`, naming what
292  holds its state; `@x[idx(...)]` reads its nearest step instead, as `p[idx(...)]`
293  does a signal passed in as parameter `p`, and any `idx`, as
294  `idx(t - 5ms - 2ms*sin(2*pi*t))`, is read sample by sample. An edit to a
295  stream plays from the next sample on.
296
297  A render keeps in a store on disk its target and, under it, each node of
298  samples that holds state (a filter, a discrete loop or a solver in it) or
299  that two or more nodes read. Nothing else is kept. A closed form, `sample`
300  of one and `rand` have a value at any instant and are computed where read.
301  A node without state that one node alone reads, however many times, is
302  computed again by that reader from what the node itself reads: no other
303  reader could ask for it, and without state it restarts at any sample, where
304  a filter or a loop must run from its start. So a stage worth keeping is a
305  node of its own that ends in a filter or a loop, or one two nodes read. A
306  kept value is named by what it computes: never its file's name, directory,
307  comments, spacing, or the order its named arguments are written in, so a
308  renamed or moved copy, a constant lifted into a default, an expression split
309  into a file of its own or written back inline, and two addends swapped all
310  read one entry. The next render of anything that reads the same value reads
311  it back, bit for bit, and computes nothing under it. The store is on by
312  default, at `$XDG_CACHE_HOME/sva`, else `~/.cache/sva`; `--cache <path>`
313  moves it (a `/dev/shm` path keeps it in memory) and `--cache none` turns it
314  off. It holds at most {store_gb} GB, the least recently used values going
315  first, and a store another build of sva-cli wrote is emptied when opened. A
316  render stages what it computes beside the store as it goes, and the store
317  itself is written once, when the render ends, fails, or is stopped by SIGINT
318  or SIGTERM.
319
320  `ledger` prints one row per node under the target. A row's `share` is the
321  part of its reader's own energy that row accounts for, so one reader's refs
322  sum to 1; a ref no addend isolates, such as one factor of a product, and
323  every row under a silent reader, which has no energy to share out, print
324  `null`. A ref carrying a share reads as the addend it gave its reader, its
325  `rms`, `peak` and `clipped` too: in `2*@a`, `a`'s row is `a` doubled, and in
326  `@a - @a` it is silence. Each ref carrying a share is collapsed once on its
327  own, so a ledger costs one collapse per attributed ref beyond the render,
328  and `depth` bounds how many, counted in refs from one file to another. Every
329  row is computed whole over the range, however late a reader reads it.
330  `brief=1` keeps only the rows that clipped, `skim=1` drops the wider fields.
331
332  `arguments` renders nothing: for every instance under the target it prints
333  each builtin call's named arguments as the numbers the call was lowered
334  with, a solver's whole parameter set with `written: false` on each default
335  it filled in, and the operand each `min`/`max` `chosen` where a call folds
336  one to a number: in named arguments and a solver's, modal bank's or
337  `noise`'s positionals. One inside a filter's or cast's positional or
338  `rand`'s key or seed is not listed. `at` spans are bytes of the instance's
339  own body, as `sva-cli outline` counts them.
340
341REPRESENTATIONS:
342  Each one a `--representation` call, its arguments in parentheses, every
343  default under DEFAULTS. `exact` is read off the written math, `measured` off
344  samples.
345
346{representations}
347
348SOLVE:
349  sva-cli solve '<cost>' --vary <name>=<lo>..<hi>[/<step>][,log]...
350                [--max-renders <n>] [--step-tol <x>] [--cost-tol <x>]
351                [--set <name>=<text>]... [--rate <hz>] [--threads <n>]
352                [--cache <path|none>] [--write [--confirm]]
353
354  Fits variables under `variables/` so the targets a cost reads match a
355  reference, and prints the values it found. It edits no file unless `--write
356  --confirm` says so.
357
358  The cost is one expression typing to one number. Its leaves are
359  `repr.<reading>(<target>, <args>)`: `<reading>` spelled as `--representation`
360  spells it, `<target>` any render target with its interval as render writes
361  one, `<args>` the reading's own: `repr.pitch(@lead([0, 2s], f0=C4),
362  frame=50ms)`. Every leaf is measured off its target's samples, as `analyze`
363  reads a file, so a recording and a render are read alike. Two leaves of one
364  reading with one set of arguments subtract to a residual vector:
365{rules}
366  A level is floored at {floor} dB before it subtracts. A residual inside both
367  sides' stated bounds counts as zero; of these readings only `onsets` states
368  one. Then `norm(v)` (the root of the sum of squares), `sum(v)`, `max(v)`,
369  `abs(x)` (each value's magnitude), `dot([w1, w2, ...], v)` (one literal weight
370  per value), numbers, `+`, `-`, `*` and `/` make one number. A reading left
371  unsubtracted, a vector left unreduced and a leaf of any other reading refuse
372  before anything renders. `repr.` is legal only here; in a node it refuses as
373  `repr-outside-solve`.
374
375  `--vary <name>=<lo>..<hi>[/<step>][,log]`, once per variable, names a file
376  `variables/<name>` holding one number and the box it moves in, both bounds in
377  one unit: none, `hz`, `khz`, `s`, `ms`, `db`, `ct` or `st`. The search starts
378  at the file's value read in that unit (`0.5` is `-6.02db` under `db` bounds).
379  `/<step>` is the first step and the grid values land on, counted from `<lo>`;
380  without it the first step is a quarter of the bounds' span. `,log` moves it on
381  a log scale, where `/<step>` is the ratio a step multiplies by, a bare number
382  above 1, as `/1.25`. A name with no file, a file holding no number in that
383  unit, and a variable no target of the cost reads each refuse before the first
384  render. `--set <name>=<text>` holds a variable at `<text>`, as render takes
385  it; a name both set and varied refuses.
386
387  The search is a deterministic compass search: from its best point it renders
388  each variable one step up and one down, in the order the `--vary`s are
389  written, and moves to the best of them that improves; where none does, every
390  step halves. A point already rendered is not rendered again. One render
391  renders every target of the cost once, through render's own path, and takes
392  every reading. A target no variable reaches, such as the reference, is read
393  back from the store on every render after its first, and `trace` shows it
394  computing no samples. A solve stops `converged` once every step is under
395  `--step-tol` of its first step or the cost is at most `--cost-tol`, `budget`
396  after `--max-renders` renders, and `cancelled` on SIGINT or SIGTERM. The
397  budget is a result, warned as `solve.budget`, not an error. Each render
398  prints one JSON line on stderr:
399    {{"render": 3, "values": {{"gain": "0.4"}}, "cost": 1.25, "best": 0.98}}
400
401  `--write` writes each fitted value to its `variables/` file, its comment line
402  kept. A file it would change refuses as `conflict` unless `--confirm` is
403  written too; that refusal still carries the fit, and `would_write`, nothing
404  written. A cancelled solve writes nothing.
405
406  Its `data`:
407    {{"cost_expression": "...", "values": {{"gain": {{"value": 0.5, "text": "0.5",
408      "unit": "", "start": "0.3", "on_bound": false}}}}, "cost": {{"total": 0.09,
409      "terms": {{"items": [{{"term": "norm(...)", "value": 0.08}}], ...}}}},
410      "renders": 49, "stopped_by": "converged", "resampled": {{"items": []}},
411      "trace": {{"items": [{{"render": 1, "values": {{"gain": {{"value": 0.3,
412      "text": "0.3"}}}}, "cost": 52.1, "computed_samples": {{"@tone": 44100,
413      "sample(\"../ref.wav\")": 44101}}}}]}}}}
414  `values` is the best point, each `text` as `--set` and a file take it; `cost`
415  its total and each top-level `+` or `-` term's signed share; `trace` every
416  render in order. A value `on_bound` sat on a bound, warned as
417  `solve.on_bound`: widen it, or the model lacks what the reference holds.
418  `--write` adds `written`, each path with its `from` and `to`. Stopped by a
419  signal, the answer is the error `cancelled`, exit 130, its `data` the best so
420  far.
421
422ANALYZE:
423  sva-cli analyze <file.wav> --representation <list> [--confirm]
424
425  Runs the same readings over a whole external `.wav` at its own rate, never
426  resampled. Only the readings a buffer answers alone apply, each listed under
427  REPRESENTATIONS as `measured` or `exact off a closed form, measured off
428  samples`; the rest need the graph behind it.
429
430LINT:
431  sva-cli lint ['<expression>'] [--format <json|text>]
432
433  Checks the current directory without rendering a sample. With no target it
434  checks every file under its own rules, and types every entry point, which
435  types every file it reaches. With a target, in render's grammar, it checks
436  the files that target reaches, and prints the interval a render of it reads.
437  Either refuses a type error as `render` does.
438
439  A score's annotation is its doc comment, under the same codes, and its lines
440  no body, so the length checks pass it by; a file of two or more lines that is
441  neither a score nor a scale refuses as `multiline-body` before any check
442  runs. Each song lint types prints its warnings beside the findings.
443
444  Every check prints one `data.diagnostics` item. `warning` exits 0, `error`
445  exits non-zero, so branch on the verdict and never on whether the array is
446  empty. No flag downgrades an error.
447
448  error    missing-comment       no `;` comment line
449           multiline-comment     more than one
450           malformed-comment     not four ` | ` fields, `Models:` `Neglects:`
451                                 `IO: <in> -> <out>` `Tags: <tag>[, <tag>...]`
452           long-comment-block    a `;` block over 1000 characters, the line-1
453                                 doc comment's own run exempted
454           long-expression-body  a body over 10000 characters, a backstop rather
455                                 than a complexity budget
456           literal-sample-rate   a written rate where `sp` belongs
457           arity                 a builtin called without an argument it reads,
458                                 or with one it does not, as `rand(seed=k)`
459  warning  key-is-not-a-pitch    `variables/key` holds neither a note name nor
460                                 a number of hertz
461           parameter-has-no-default
462                                 a node reads a parameter no `name = value` line
463                                 binds, so a bare `@node` cannot play
464           support-never-ends    a node's support, cut where its bound falls
465                                 under the silence threshold, has no end for a
466                                 bare render to stop at
467
468TRACE:
469  sva-cli trace <node|expression>
470
471  Prints one node's position without rendering audio: what it reads (`down`, one
472  hop), everything that reads it (`up`, transitively to an entry point), each
473  beside the expression doing the reading, the node that made it discrete, and
474  the feedback loop it sits in, if any. A score is shown as its line count, its
475  first and last `at` and the nodes it plays, never the sum it lowers to; every
476  entry point's song is lowered first, each at song time 0. An interval the
477  target reads is ignored.
478
479BUILTINS:
480  sva-cli builtins
481
482  Prints the whole callable and syntactic vocabulary: every builtin with its
483  arity and named arguments, each argument's `meaning`, `unit`, the model
484  `part` it sets and whether it `moves` with `t` (a filter's cutoff, q and gain;
485  every other named argument is one number, refused when it names none), each
486  positional's meaning where the model states one, unit suffixes, the note-name
487  grammar, the scales `variables/scale` may name with their cents, reserved
488  identifiers, special call shapes, and what has no operator at all.
489
490OUTLINE:
491  sva-cli outline <expression>
492
493  Prints the parse tree the engine builds from one expression, each node with
494  the byte `span` it was written in: calls by `name` with positional and named
495  `args`, operators by `op`, refs by `path` with their `binds`, refs and `self`
496  by how they `read`, `time` or `index`, literals by `value` and `unit`, names
497  by `name`. A node the parser supplies itself, the `0` of a prefix minus or the
498  `t` of a bare `@ref`, has `written: false`. Reads no composition. Score text,
499  JSON opening with `{{`, prints `score` instead of `outline`: one item per item
500  a line lists, with its `kind`, `line`, `span`, `at` with marks resolved, and
501  its `node`, `deg`, `args`, `mark` or `lane`, `to`, `len` and `shape`.
502
503  sva-cli outline @score/song
504
505  Run in a composition, outlines that score as the song a render of it is:
506  `marks` in bars and seconds, the `tempo` curve's pieces, each lane with its
507  home and every move resolved with its placement chain, how many instances it
508  reaches and how many see it move, and each placed event once, however many
509  reads reach it: its song time `at` (where it reads lanes, key and scale), when
510  it first `sounds` (later by the least, over the reads reaching it, of the
511  delays of the `t - d` reads of a score above it), its `len` in song time where
512  its line writes one, node, pitch in hertz and where each parameter comes from
513  (`line`, `lane` or `default`), and the `size`: placed events and the engine's
514  instances beside its limit.
515
516NEW:
517  sva-cli new <name> [--idempotency-key <key>]
518
519  Writes a starter composition at ./<name>, and refuses if that directory
520  exists. `--idempotency-key <key>` records the key beside the composition, so a
521  retry under the same key succeeds identically while the tree still holds what
522  was written. Any other key, or an edited tree, refuses.
523
524EXAMPLES:
525  sva-cli new song1 && cd song1
526  sva-cli render '@master' --representation samples=/tmp/song1.wav
527  sva-cli render '@master([0, 8b])' --representation 'ledger(depth=2),loudness'
528  sva-cli render '@voice/note([0, inf), f0=C4, len=2s)' \
529    --until 'envelope(t) < -60db and t > 1s' --representation samples=/tmp/note.wav
530  sva-cli render 'sample(@chord/home)' --representation 'spectrum(peaks=8)' --rate 48000
531  sva-cli render 'sample(@voice/note([0, 2s], f0=C4))' --representation pitch
532  sva-cli render '@master' --set key=G3 --set bpm=140 --set scale=dorian \
533    --representation samples=/tmp/song1-g.wav
534  sva-cli render '@master' \
535    --representation 'samples(buffer=100ms)=alsa:default,loudness'
536  sva-cli solve 'norm(repr.bands(@master([0, 4s])) - repr.bands(sample("../ref.wav")))
537    + 0.5*norm(repr.loudness(@master([0, 4s])) - repr.loudness(sample("../ref.wav")))' \\
538    --vary gain=0..2/0.25 --vary cutoff=200hz..8000hz/1.25,log --rate 48000
539  sva-cli solve 'sum(abs(repr.onsets(@score/song([0, 8s]))
540    - repr.onsets(sample("/tmp/take.wav"))))' \\
541    --vary bpm=100..140/2 --set key=D3 --max-renders 60 --write --confirm
542  sva-cli lint
543  sva-cli lint '@master'
544  sva-cli trace score/phrase
545  sva-cli outline @score/phrase
546  sva-cli builtins
547
548OUTPUT:
549  {{"status": "success", "data": {{"target": "@master([0, 8b])", "sample_rate":
550  {DEFAULT_SAMPLE_RATE}, "bits": {bits}, "profile": "psychoacoustic-v1",
551  "interval": {{"start_secs":
552  0, "end_secs": 16}}, "label": {{...}}, "written": {{"items": [...]}},
553  "representations": {{"ledger": {{...}}}}, "diagnostics": {{"items": []}}}},
554  "meta": {{"request_id": "req_...", "timestamp": 1700000000}}}}
555
556  `interval` is null where no reading read samples. An error adds "error":
557  {{"code", "message", "details": {{"count", "codes"}}}}. Success or error,
558  every response carries every finding in full at "data": {{"diagnostics":
559  {{"items": [{{"code", "severity", "message", "location", "help"}}],
560  "pagination": {{"count", "has_more", "next_cursor"}}}}}}, empty where it found
561  none.
562
563  Every collection carries that same {{items, pagination}} pair. `count` is the
564  whole reading's, `has_more` says `items` holds less than that, and
565  `next_cursor` is the interval start, as `0.5s`, the rest is read from. A
566  reading written to a file is written whole, uncapped. This page is an
567  envelope of its own, at "data": {{"help"}}.
568
569DEFAULTS:
570  --rate <hz>          the one rate a render samples at, and `1sp`.
571                       Default {DEFAULT_SAMPLE_RATE}.
572  --bits <n>           the precision every sample is written to. Default {bits},
573                       the `psychoacoustic-v1` profile's own.
574  ledger(depth=<n>)    how deep below its target a `ledger` walks.
575                       Default {DEFAULT_LEDGER_DEPTH}.
576  (peaks=<n>)          peaks a `spectrum` keeps, notes a `pitch`, formants a
577                       `formants`, stripes and novelty peaks a `self_similarity`
578                       lists per view. Default {DEFAULT_MAX_PEAKS}.
579  alias(oversample=<n>) the multiple `alias` re-renders at to hear what folded.
580                       Default {DEFAULT_OVERSAMPLE}.
581  (frame=<t>)          the step a framed reading advances by, in seconds.
582                       Default {DEFAULT_FRAME_SECS}, except `spectrum`, which sizes
583                       its own transform to the range unless it is set.
584  (floor=<db>)         the amplitude, as `-40db`, under which a harmonic reading
585                       or `self_similarity` drops a partial, and under which
586                       `self_similarity` counts a band level as zero.
587                       Default {DEFAULT_FLOOR_DB}db.
588  bands(prune=<0|1|db>) the level, as `0.5db`, each band's knots stay within
589                       of its track at every source sample; `1` is
590                       {DEFAULT_PRUNE_DB}db. Default 0: every band's 2 kHz track.
591  bands(floor=<db>)    under each band's peak, as `-80db`, where a pruned track
592                       is cut. Default {DEFAULT_BAND_FLOOR_DB}db.
593  voice_leading(norm=<l1|l2>) how a voice leading's moves add up. Default l1.
594  dissonance(pairs=<n>) the most partial pairs one frame sums before it refuses.
595                       Default {DEFAULT_MAX_PAIRS}.
596  periodicity(window=<t>) the span of onset strength one window autocorrelates,
597                       in seconds, at least twice the shortest period it reads;
598                       it reads periods up to half its span.
599                       Default {DEFAULT_PERIODICITY_WINDOW_SECS}.
600  periodicity(curve=<0|1>) `1` adds every window's height at every lag.
601                       Default 0.
602  modulation(window=<t>) the span of band envelope one window transforms, in
603                       seconds, at least twice the fastest rate's period; it
604                       reads rates down to two periods per span.
605                       Default {DEFAULT_MODULATION_WINDOW_SECS}.
606  modulation(bpm=<n>)  a tempo, as `140`, adding each rate's period in beats.
607                       Default none.
608  self_similarity(cell=<t>) the side of one matrix cell, in seconds, a whole
609                       number of frames holding a sample of the band
610                       envelopes; the target may span at most
611                       {MAX_CELLS} cells. Default {DEFAULT_CELL_SECS}.
612  self_similarity(smooth=<t>) the length each diagonal is averaged over
613                       before stripes are picked, in seconds.
614                       Default {DEFAULT_SMOOTH_SECS}.
615  self_similarity(window=<t>) the whole width of the novelty kernel, in
616                       seconds, at most {MAX_CELLS} cells a side.
617                       Default {DEFAULT_NOVELTY_WINDOW_SECS}.
618  self_similarity(curve=<0|1>) `1` adds every cell's chroma and band levels and
619                       each view's matrix. Default 0.
620  bindings(node=@<path>) the instance whose bindings are read; required. An
621                       instance is named exactly as the render spells it; any
622                       other spelling refuses, listing its file's instances.
623  samples(buffer=<t>)  how much an `alsa:` device holds ahead of what it plays,
624                       in seconds. Default {DEFAULT_BUFFER_SECS}; only a device
625                       has one.
626  ledger(brief, skim)  `0` unless set `1`.
627  --format <json|text> how `lint` prints its findings: the envelope, or one
628                       terminal line each, colored where stdout is a terminal.
629                       The same objects either way. Default json.
630  --cache <path|none>  where the store lives. Default `$XDG_CACHE_HOME/sva`, else
631                       `~/.cache/sva`, holding at most {store_gb} GB; `none` keeps
632                       no store. A store that fails fails no render: it answers
633                       as without one, warned why in `diagnostics`.
634  --set <name>=<text>  a variable read as `<text>` for this render, or held for
635                       a solve. Default none: each is read off its file.
636  --max-renders <n>    the most renders a solve takes. Default {max_renders}.
637  --step-tol <x>       the fraction of each variable's first step under which a
638                       solve's search stops. Default {step_tol}.
639  --cost-tol <x>       the cost at or under which a solve stops. Default {cost_tol}.
640  --write              a solve writes its fitted values to their `variables/`
641                       files, with `--confirm`. Default off.
642  --confirm            replaces a destination that already holds a file. Without
643                       it a path already taken refuses as `conflict` and nothing
644                       is written.
645
646ENVIRONMENT:
647  SVA_LOG=debug        `render` logs, once it ends, what it asked of each value
648                       to stderr; stdout and the samples are unchanged. Any
649                       other value, or none, logs nothing. One line per second
650                       of output, then one per node and a total:
651                         sva-cache pass hit=0 miss=190 ... reused=0 cum-hit=0.0%
652                         sva-cache t=1.022s hit=1 miss=2 ... cum-hit=0.5%
653                         sva-cache node hit=1 miss=0 ... reused=3 <node>
654                         sva-cache total hit=1 miss=198 ... hit-rate=0.5% ...
655                       `pass` is what was looked up before the first block.
656                       Each value is looked up once: a `hit` was answered by
657                       the store, `prefix` found a stored run up to a switch,
658                       `miss` computed it, `new` held it in memory, where the
659                       store takes what it keeps from. Each read of a value
660                       past its first is `reused`.
661
662EXIT CODES:
663  0  success (error.code absent)
664  1  internal_error (a destination could not be written)
665  3  validation_error (bad arguments, a composition that failed to parse, or a
666     render the engine refused)
667  4  conflict (a name `new` would overwrite, a destination already holding a
668     file, or a variable file `solve --write` would change, without `--confirm`)
669  24 not_found (a `.wav` file, a `sample("<path>")` naming no file, or a node
670     this composition does not define)
671  130 cancelled (a solve stopped by SIGINT or SIGTERM, `data` the best so far)
672
673VERB ALIASES:
674  validate = lint, list = builtins, create = new, show = trace, from the `cli`
675  standard's own verb list. `render` and `analyze` take a reading, which that
676  list has no word for, so they keep their own names.
677
678SEE ALSO:
679  sva-cli --version    Show version information"#
680    )
681}
682
683/// One line per reading a cost subtracts, off the table the subtraction itself keeps.
684fn solve_rules() -> String {
685    let mut out = Vec::new();
686    for (name, rule) in solve::RULES {
687        let mut line = format!("    {name:<10}");
688        for word in rule.split(' ') {
689            if line.len() + 1 + word.len() > 80 {
690                out.push(line);
691                line = " ".repeat(15);
692            } else {
693                line.push(' ');
694            }
695            line.push_str(word);
696        }
697        out.push(line);
698    }
699    out.join("\n")
700}
701
702/// One entry per reading, off the one table: its call, what it answers off, and its line.
703fn representations() -> String {
704    READINGS
705        .iter()
706        .map(|row| {
707            let keys: Vec<&str> = row.takes.iter().map(|arg| arg.key()).collect();
708            let call = match keys[..] {
709                [] => row.name.to_string(),
710                _ => format!("{}({})", row.name, keys.join(", ")),
711            };
712            let source = match row.reads {
713                Reads::ClosedForm | Reads::Structure => "exact",
714                Reads::Either => "exact off a closed form, measured off samples",
715                Reads::Samples => "measured",
716                Reads::Graph => "measured, and the graph behind the samples",
717            };
718            format!("  {call:<26} {source}\n      {}", row.help)
719        })
720        .collect::<Vec<_>>()
721        .join("\n")
722}