Changelog

Documentation | Example Gallery | Web App

[1.14.0] - 2026-08-27

Added

• The notation has a map. The reference the gem ships (--notation) is one page: the characters that already mean something, then every feature at a line each with the notation beside it, then the options. Both manuals open with the same list, each row pointing at the section that explains it. A test reads the feature set out of the grammar itself and draws every sample, so a feature the grammar gains with no row in the documents fails the build, and a sample that stops meaning what it says fails with it.
• The changelog is on the documentation site, at /changelog, built from CHANGELOG.md and linked from the manuals and the README.

Changed

• Every release in the changelog is dated to the day, from the git tags. Two of the old month-only dates were wrong.
• What the trap section warns about is now, by definition, what the tool accepts and draws as something other than what was meant. A mistake the tool refuses is the error message’s job, and its card has come down; the warning about parentheses, which the Penn Treebank conversion had made false, tells the truth again.
• The arrow markers’ dimensions are rounded; the defs of every SVG carried float dust in an attribute.

Fixed

• Turning derivation on no longer deletes a column from a node that has no daughters. A rule name is written after a column break and names the step that produced a node from its daughters, so a node with none names no rule — but the label is read before the tree is built, and the name was taken out anyway and then had no rule to be drawn beside. [A\tfoo] drew “A foo” with the option off and “A” with it on. The label is put back once the tree is known.
• A mistake inside a node’s label keeps the name of what is wrong with it. The first raw space splits a token into a label and its children, and when the label would not parse, every cause but one was relabelled “a raw space split this” — so the message named an unknown colour while the code and the hint talked about spaces, and a caller acting on the code was sent to fix what was not wrong. Which story is right is now asked of the parser rather than guessed: the token is put back together with its spaces written as the notation writes them, and if it reads, the space was the cause.
• A hex colour is three digits or six, which is what every message about colour here already said. The grammar asked for three to six, so four and five parsed, passed the validator — which does not look at a value beginning with # — and reached librsvg, which cannot read them and draws the label black without reporting it.

[1.13.2] - 2026-08-27

Fixed

• A movement path is drawn as one stroke with its corners eased, in place of three lines meeting at right angles. The dash of a non-directional path now runs round each turn instead of restarting at it, and the arrowhead is the end of the stroke rather than a marker on whichever line finished last. The radius is held down to half of each run it joins, so a short leg cannot be swallowed by its own turn, and to the length of an arrowhead where there is one, so the head is never drawn onto the curve. Three gallery figures carry paths and change with it.
• Digits are set in the text face again on machines that have a colour emoji font. The font chains named emoji families by name, and asking fontconfig for one is asking for the generic emoji family, whose preference list fontconfig then prepends to the whole pattern with a strong binding — so the emoji face arrived ahead of the Noto text faces rather than behind them. A colour emoji font carries the ASCII digits, for keycap sequences, so on an ordinary Linux desktop [N 20] came out in the emoji face at more than twice the width. Measurement and drawing read the same chain, so the figure held together; it was simply not the figure the same input gives elsewhere. No emoji family is named now: a codepoint no named family covers reaches fontconfig’s own fallback, which is the path this was duplicating. Emoji draw as before, and the gallery is unchanged to the pixel — every raster figure is byte-identical and the SVGs differ only in the family list they carry.

[1.13.1] - 2026-08-27

Fixed

• ^ at the head of a leaf draws the triangle it asks for. The mark may be written on the node’s label or on the leaf’s own text — [^NP cats] and [NP ^cats] — and the documentation, the notation reference and the gallery all use both, but only the first was drawn: the second lost its caret to the parser and then a bar was drawn under it. The two now produce the same figure in every connector style, and LSIF records the edge as a triangle. Three gallery figures change accordingly, each toward what it was written to show.
• An option given as an empty string is read as an option not given, rather than as a value no list contains. An HTML form posts a field for every control it carries, and a control with nothing selected posts the empty string, so a form that has outlived one of its own controls sends that field empty alongside the rest. Since option validation arrived in 1.11.0 that failed the whole request: the web UI’s Download buttons answered 500 for every input, because the form still read a format select the page no longer had. A value that is actually wrong is still rejected.

[1.13.0] - 2026-08-24

Added

• Derivations. A derivation puts the words first and the result last, and joins what each step combines with one rule drawn across all of it rather than with a line to each daughter. derivation draws the rules and direction: btt turns the tree over; together they give the format categorial grammar is written in, and derivation on its own marks the spans of an ordinary tree. The name of each step rides in the label after a column break and is set beside the end of its rule. A derivation runs down the page and is drawn with its rules, so direction: ltr and hiding the default connectors are refused rather than approximated.
• direction: btt, the layout turned over, leaves first.

Fixed

• Connectors follow the tree when it is turned over. They kept the ends they have when the root is at the top, so every line ran from above the daughter, through its label and the mother’s, to below the mother.

[1.12.0] - 2026-08-22

Everything needed to write this notation is now available as text, built from the files the tool itself reads, and a refusal says where that text is.

Added

• --examples prints every published example with the options it was drawn with. The gallery examples are checked against the parser that draws them, so each one is known to be accepted.
• The site carries the same material as plain text for a reader that can fetch a URL but cannot run a command: llms.txt and llms-full.txt, the second holding the reference, the manual and every example in one file. Both are generated from their sources, and a test fails if they fall behind.
• A refusal names where the notation is written down, once, alongside the cause and the fix. A hint repairs the mistake in front of it and says nothing about the rest, which is not enough for a caller that was guessing.

Changed

• The angle bracket the reference recommends is U+27E8 and U+27E9, which it had always named while writing U+3008 and U+3009 in its own examples. The East Asian pair draws a full em wide, wider than a capital, and had spread through the gallery and into the repair that corrects ASCII brackets. Both pairs still parse; documents written before this are unaffected.
• Two feature-structure figures are redrawn at the narrower bracket.

Fixed

• --notation and --examples answer before the input is read. Reading first meant waiting on a pipe that never closes when stdin is not a terminal, which is how a script reaches them.

[1.11.0] - 2026-08-21

Every input the tool accepts now draws, and every input it refuses says why. Line thickness follows the type size, so figures drawn at any font size keep the same balance between text and rules — existing figures come out about a fifth lighter than before.

Added

• --validate checks input without drawing or writing a file, reporting a machine-readable diagnosis on stdout and the verdict in the exit code.
• --notation prints a short reference for the notation, which now ships with the gem.
• Errors carry a code, the offending label and an offset inside it, a one-line fix, and whether rewriting the input could help. The message text is unchanged. Each cause is confirmed by applying its fix and parsing again, so a named cause is one whose fix is known to work.
• A label may be nothing but a matrix: [#(HEAD\tnoun#)] had no spelling before, since the enclosure rule took the # first.
• -f tikz on the command line, which the documentation had offered while the CLI rejected it. TikZ output also carries the line width, which it had been accepting and dropping.
• A gallery figure and a heading of its own for levelling the terminals with <> joints.

Changed

• Line width is a fraction of the font size rather than an absolute number. 1 is five per cent of the type size at any size, and the scale runs from 0.5 to 3.0 in halves where it ran 1 to 5 and meant 2 to 6. Lines were two units wide whatever the type size, which read as heavily as a serif stem at 16 point and heavier still below that, and nothing thinner was available.
• On/off options accept every spelling of off. mirror: "no" reversed the tree and transparent: "0" cut the background away, because anything but "off" and "false" was read as on.
• Option values are checked against the values the option takes. A value nobody defines was taken and read as something else — direction: "left-to-right" laid the tree out top to bottom. The CLI has always refused these; the library did not, which left the web interface and other programmatic callers unguarded.
• Colour names are checked against the CSS colour names. A name nobody defines passed validation and drew black.
• Penn Treebank input converts in the library, not only in the CLI. Other callers got no conversion and no error: (S (NP the dog)) drew as one leaf containing that text.
• Font sizes go down to 6, which the web interface has always offered while the documentation said 8.

Fixed

• Validation accepted input that drawing then refused: a movement path with one end, a tree too wide for a raster surface, a colour spec that fails only when the label is parsed. It now generates the drawing and discards it, going as far as the requested format can still refuse.
• A malformed colour was reported as an unclosed enclosure, sending the writer to fix a # that was never the problem.
• A left-to-right matrix drew its brackets on top of the attribute names.
• Text in front of a tree crashed symmetrization, and an empty argument was read as a path to the current directory.
• Overline was documented as missing from PNG output. It has been there.

[1.10.0] - 2026-08-19

A transitional release ahead of 2.0, which drops JPG/GIF output and the RMagick dependency.

Deprecated

• JPG and GIF output: the CLI prints a warning to stderr when either is requested, and the documentation marks both as deprecated. JPEG blurs line art and GIF has no use case here — use PNG. Both formats are removed in 2.0.

Changed

• The library no longer loads RMagick at require time. SVG, PNG, PDF, TikZ and LSIF work without ImageMagick installed; only a JPG or GIF request needs RMagick, and a request without it reports the missing dependency as a regular input error instead of a bare LoadError.

Fixed

• RSTError mutated the message it was given, so raising one with a plain string literal crashed inside the error class with a FrozenError. Every file here carries frozen_string_literal, which made the working form the unobvious one.

[1.9.0] - 2026-08-19

Added

• hyphen: literal, which trades the two readings of a hyphen: a bare one is a hyphen and \-underlined\- underlines. Feature names in HPSG and its relatives are full of hyphens, and escaping each one is a poor trade for a rule that work never uses.
• A matrix nested in a label, written between #( and #). The value of an attribute can be another attribute-value matrix, to any depth, which is what a feature path such as SYNSEM | LOCAL | CATEGORY | HEAD needs and what HPSG, SBCG and LFG are written in. The nested matrix draws its own brackets and lays out its own columns, and the rows after it clear its full height.
• \t in a label cuts the line into cells. Every line is cut at the same points and each column is drawn at the width of its widest cell, so the parts line up down the label. Together with the bracket enclosure and the horizontal rule this gives attribute-value matrices — the feature structures of HPSG, SBCG and LFG — without spacing each row by hand, which is how the gallery’s HPSG example used to do it.
• color: gray, a scheme that keeps node and leaf labels black and draws the connectors, triangles and movement paths in grey. It is for diagrams whose links outnumber their labels — an ontology, a network of constructions — where a page of black lines buries the text. grey is accepted too.
• Gallery examples for two more frameworks: LFG (an annotated c-structure and the f-structure it maps to, after Kaplan & Bresnan 1982 and Bresnan 2001) and DRT (a discourse representation structure, after Kamp 1981).
• The example gallery scales each figure by its own width rather than by one factor for all of them, so a small tree and a wide one are read at a similar apparent size; a figure now fits its row instead of scrolling, loads lazily, and carries an anchor of its own.

Changed

• Every box and circle in a figure is drawn at one size and on one centre line. The size used to come from the line’s height, which left a box standing a head taller than the numeral inside it, and each shape was centred on its own glyph, so the box around s sat lower than the one around G. A shape is now drawn at a fixed fraction of the font size, centred on a capital, and grows only for content that will not fit. Every figure with a boxed or circled label is redrawn.
• The SVG’s declared width and height agree with its viewBox. They did not, so every figure was scaled down by a few percent and letterboxed inside its own canvas.

Fixed

• TikZ export dropped everything inside a nested matrix: a feature structure came out as its outermost attribute names and nothing else. The export still cannot draw the brackets, but it keeps what they hold. The documented list of what TikZ does not carry now names column alignment, nested matrices and the grey line scheme.
• LSIF records which of the two readings of a hyphen the input was parsed under. It records the input verbatim, and the same string means different things under the two, so a reader could not re-parse it.
• A line-type connection with only one end raised a NoMethodError from inside the drawing instead of being reported as the input error it is.
• A line-type connection between two nodes was anchored a full inter-node gap outside each of them, so the link fell short of both boxes where the gap was wide and reached inside them where it was narrow. It now runs between the boxes’ own edges, a quarter of a gap short of each. The double arrowhead keeps the shape it had but is sized to the link, instead of one fixed size that spilled over both boxes on a short link. The same anchors are used in left-to-right layout, where a link between siblings had been drawn diagonally from the movement-path anchors and now runs straight between the facing edges.
• Two nodes joined by a line-type connection are laid out far enough apart for a full-size arrowhead between them. Where the layout had packed them closer than the arrow is wide — the two leaves at the foot of the quicksort figure — the arrow was drawn small to fit; now the pair is spread and the arrow keeps its size. Only pairs that carry a link move, and only when they need to.

[1.8.2] - 2026-08-17

Changed

• tidy: high now compresses as far as its name promises. The level-balance floor added in 1.8.0, which keeps a pair of siblings from being tucked narrower than the level below it, applied to medium and high alike and bound first in nearly every tree: across the 75 gallery examples the two modes produced identical figures 70 times. The floor now applies to medium only, leaving high free to trade even branch angles for width — 29 of the 75 examples now differ, by up to 19%. off, low and medium are unchanged; high, like symmetric at the other end of the scale, is for figures that ask for it.
• Mathematical alphanumerics (U+1D400–, such as the little v of vP) are named in the family chains. Neither Noto Sans nor Noto Serif covers the block, so the glyphs came from whatever the machine offered: Noto Sans Math on Alpine, DejaVu Serif on Debian/Ubuntu, STIX Two Math on macOS. The serif style now asks for a serif source first, so a serif tree no longer shows a sans v. The Docker images install font-dejavu for it.

Fixed

• The CLI printed parse errors to stdout and exited 0, so a script generating figures in bulk could not tell a rejected input from a drawn one. Errors go to stderr and the exit status is 1.
• Dropped Noto Sans Mono SemiCondensed from the mono chain. It is a width style of the variable Noto Sans Mono rather than a family of its own, and resolved nowhere on macOS, Debian/Ubuntu or Alpine; the chain fell through to Noto Sans Mono, which it now names directly.

[1.8.1] - 2026-08-15

Fixed

• Arabic rendered as isolated, unjoined letterforms in some environments. Scripts outside Latin and CJK were left to the system’s generic font fallback, which is not the same font on every machine: on Alpine the Arabic block was claimed by Noto Sans Math, which has the glyphs but no joining rules, while on Debian/Ubuntu the same text fell to DejaVu Sans. The family chains now name the scripts the gallery covers — Arabic (Noto Sans Arabic, with Noto Naskh Arabic for the serif style), Hebrew, Devanagari, Thai and Khmer — so machines that have those fonts installed produce the same shapes. Mathematical alphanumerics (U+1D400–) are not named yet and still vary by environment. Gallery example 067 (Arabic) was affected and has been regenerated.
• Emoji were measured with one font and drawn with another where a colour emoji font was installed: Pango selects Noto Color Emoji, but the librsvg/Cairo pipeline does not rasterise its bitmap glyphs, so the drawing fell back to whatever outline font happened to cover the codepoint. The project’s Docker images now install the monochrome Noto Emoji and leave the colour build out.

Changed

• The Docker images install the Noto packages for Arabic (including Naskh), Hebrew, Devanagari, Thai and Khmer, and carry a fontconfig rule that removes the Arabic ranges from Noto Sans Math while keeping its mathematical alphanumerics (used for the little v of vP).
• Documentation records how to override any of the named families with a fontconfig alias, for users who prefer their own script fonts.

[1.8.0] - 2026-08-15

Added

• tidy layout scale, one option covering every layout mode from the most spacious to the most dense: symmetric (radical symmetrization) | off | low (contour packing, strict leaf positions) | medium (packing with cross-row tucking that never lets two leaves swap their left-right order) | high (free tucking; leaf order kept per row only). Connector heights adjust automatically: a small height budget (5% of the tree’s height) is spent on the levels whose branches spread widest, evening out branch angles. Tidy never produces overlapping labels (collisions roll back).
• mirror option: flips the finished layout horizontally for the right-to-left tree convention of Arabic/Hebrew syntax (composes with direction).
• hspacing option: scales every horizontal gap in every layout mode — the horizontal counterpart of vheight/connector height.
• Pass-through empty nodes: a node labeled only <> renders as an invisible joint with the connector running continuously through it, so a <> chain aligns a shallow leaf with deeper leaves without a broken line.
• Full CJK coverage in every font style: the family chains fall back to Noto Sans/Serif/Mono CJK, so Hangul and simplified/traditional Han render in all styles (the standalone Noto JP faces carry no Hangul).
• Example gallery: Multilingual category (the same UD-PUD sentence in nine languages, constituency derived mechanically from the dependency annotation; the Arabic example demonstrates mirror), a Morphology category, and per-figure tidy settings across the whole gallery.
• CI on GitHub Actions (Ruby 3.2/3.4).

Changed

• LSIF output records the layout settings a reader cannot recover from the coordinates: geometry.mirror, and tidy, mirror, direction and horizontal_spacing under meta.source.params.
• The standalone symmetrize option and -y flag are deprecated aliases of tidy: symmetric; tidy_spacing is a deprecated alias of hspacing.
• --direction now owns the -d short flag (it had been auto-assigned to --hide-default-connectors, so the documented -d ltr silently did nothing). Every published short flag is now declared explicitly rather than derived from the option set. One undocumented auto-assignment moved as a result: -e was --direction in 1.7.0 and is --version here.
• The gem no longer bundles font files (38MB that were never opened at runtime since the Pango migration): fonts resolve by family name through fontconfig. See README for the system font packages. The dead --font CLI option (its value was never read) is gone.

Fixed

• Boolean options left at their defaults are no longer misread as enabled when the caller passes only a partial parameter set (e.g. tidy: off rendered as symmetric in the web UI).

[1.7.0] - 2026-08-13

Changed

• Text measurement now uses Pango, the same engine (and the same fontconfig font-fallback resolution) librsvg uses to render the output, instead of RMagick with the bundled font files. Labels in any script are measured with the font that actually draws them, which fixes off-center labels for scripts the bundled fonts do not cover (e.g. Khmer, #14) without bundling per-script fonts. Horizontal dimensions of the output may change slightly.
• Vertical rhythm is now derived deterministically from the font size (1.4 x size, matching the previous Latin line height) and is identical across scripts; the old engine spaced Japanese text 1.5x and WenQuanYi 1.25x, so mixed-language documents had inconsistent spacing.
• The font-family lists used in the SVG output and in measurement are now defined in a single place (FONT_FAMILIES / FontFamily).

Added

• Runtime dependency on the pango gem (ruby-gnome). No new system requirements: librsvg already depends on Pango.

[1.6.3] - 2026-07-19

Fixed

• Packaged files no longer carry owner-only permissions. gem build preserves on-disk modes, so gems built from a checkout with 0600/0700 files shipped a library unreadable — and a rsyntaxtree CLI unexecutable — by anyone but the owner after sudo gem install. File modes are now normalized before the gem is built: 0755 for commands (bin/, exe/) and shebang scripts, 0644 for everything else. This also drops stray executable bits that the working tree had picked up on data files (images, fonts, Markdown, CSS, library sources).

[1.6.2] - 2026-06-26

Fixed

• Region shade no longer touches the image edge when its padded bounds reach past the tree’s natural extent (e.g. a deep enclosed/multi-line node): the canvas now grows with a margin around the shaded plane.

[1.6.1] - 2026-06-26

Improved

• Region shade rendering wraps the subtree more cleanly: wider, balanced padding; bracket/rectangle enclosures are kept inside the plane; the incoming parent connector stops just short of the plane (no overlap or touching); and the margin is consistent between root and non-root regions. Works in both top-to-bottom and left-to-right layouts (the connector-facing edge is the top in TTB and the left in LTR, with symmetric padding on the other sides).

Added

• Example 065: nested (overlapping) region shades, shown as progressively darker gray.

[1.6.0] - 2026-06-25

Added

• Region shade (% prefix): paints a semi-transparent plane behind the whole subtree a node governs, for marking c-command/binding domains and cognitive grammar dominions. Color reuses the @color: syntax; bare % uses light gray. Each plane has a darker same-color border for visibility on white. An explicit shade color is always honored (consistent with @color: node text); use bare % for a gray monochrome shade. Works in both TTB and LTR layouts and across SVG/PNG/PDF/JPG/GIF.
• Region shade support in TikZ export (via forest fit to=tree) and in LSIF node style.region. TikZ region colors (names and hex, including SVG/CSS names like lightblue that xcolor lacks) are emitted as explicit RGB so the output compiles.
• \% escape for a literal leading percent sign.
• Typographic apostrophe: a straight ASCII apostrophe (') in a label is now rendered as a curly apostrophe (’, U+2019) for smarter typography, e.g. the X-bar prime in T'. Applied to all fonts and measured before layout so spacing stays correct.
• Example 064: region shade for a c-command domain.

Changed

• LSIF output version bumped to 0.3.0 (adds node style.region).

Fixed

• Region shade on the root/topmost node no longer clipped by the canvas: the SVG viewBox now grows to include region planes that extend past the tree.

[1.5.0] - 2026-04-06

Added

• Left-to-right tree layout (-d ltr / --direction ltr)
• LSIF geometry.direction field for layout direction
• LTR-aware path drawing (movement arrows route rightward in ⊃ shape)
• LTR-aware line-type connections (direct lines between nodes)
• Examples 058-063: LTR versions of classification trees and vP-shell with paths

Fixed

• Node label overlap when adjacent subtrees have long labels

Improved

• TTB path bulge proportional to endpoint distance (reduced excess)

[1.4.0] - 2026-01-06

Added

• LSIF (Linguistic Structure Interchange Format) JSON output (-f lsif)
• Per-node coloring with @color: syntax (named colors and hex colors)
• Penn Treebank format support with escaped parentheses (\(, \))
• Standard input support for piping tree data
• Configuration file support (.rsyntaxtreerc)
• Config file validation with helpful error messages

Documentation

• Added TikZ output limitations section
• Improved README with Features section
• Added examples for per-node coloring (054, 055, 056)
• Added example 057: Subscript and superscript demo

[1.3.2] - 2025-03-03

• Garbage collection friendly implementation

[1.3.1] - 2024-10-24

• Square brackets can be escaped with \[ and \]
• Bug fixes and improvements

[1.3.0] - 2024-08-27

• TikZ/forest LaTeX output support

Earlier releases (2018–2023)

Before this file was kept, the web interface carried the release notes. Moved here so the history has one home.

• 2023-09 — Cross-hatch rendering issue fixed
• 2023-02 — PDF download; improved line edges; Line width option; Traditional colour option; Hide connectors option; extra connectors between nodes
• 2023-01 — Noto Sans Mono font option
• 2022-11 — ¥ accepted in place of the backslash for escapes; documentation in Japanese
• 2022-06 — RSyntaxTree on the Web: the UI as a source package, runnable locally with Docker
• 2022-02 — Polyline connector option
• 2022-01 — comprehensive rewrite; path drawing (non-directional, directional, bidirectional); more flexible text markup; new markup patterns (newlines, brackets, horizontal lines, boxed text); triangles in every connector mode; improved error display and image zoom in the UI
• 2021-12 — subscript _text_ and superscript __text__; \n inside terminal nodes
• 2021-11 — label-less terminal nodes ([A [B] [C]]); auto bracket close; math symbol rendering; better image quality; some decoration symbols altered
• 2019-11 — SVG download error fixed
• 2019-04 — SVG colour on/off fixed
• 2018-06 — whitespace in labels with <> (Modal<>AUX)
• 2018-03 — V spacing option (then called Connector height); syntax highlighting of the input; text styles (italic, bold) and decoration (underline, overline, line-through); refined site design
• 2018-02 — margins around the image; better editor (Ace)