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Syntax tree generator made with Ruby and RMagic
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Latest commit c7d6775 Apr 22, 2016 @yohasebe minor fix

RSyntaxTree: yet another syntax tree generator in Ruby

RSyntaxTree is a graphical syntax tree generator written in the Ruby programming language. It is basically a port of phpSyntaxTree created by André Eisenbach.

While phpSyntaxTree does not accept multi-byte characters as those in Chinese, Japanese, and Korean, RSyntaxTree handles text of any language as long as encoded in UTF-8 and fonts have been installed. Additionally, RSyntaxTree can output symmetrized tree diagrams, a functionality that is not implemented in phpSyntaxTree.

RSyntaxTree consists of an easy-to-use command-line app and a web-based interface made with Sinatra web framework.

Web Interface

Working web interface of a previous version of RSyntaxTree is available at . New version will be deployed soon.


# gem install rsyntaxtree


For the web interface, see Usage section in .

For the command-line interface, type $rsyntaxtree -h after installation. Here's what you get:

RSyntaxTree, (linguistic) syntax tree generator written in Ruby.

       rsyntaxtree [options] "[VP [VP [V set] [NP bracket notation]] [ADV here]]"
where [options] are:
      --outdir, -o <s>:   Output directory (default: present working directory) (default: ./)
      --format, -f <s>:   Output format: png, pdf, or svg (default: png)
   --leafstyle, -l <s>:   visual style of tree leaves: auto, triangle, bar, or nothing (default: auto)
   --fontstyle, -n <s>:   Font style: sans-serif, serif, jp-gothic, jp-mincho, cjk (default: cjk)
        --font, -t <s>:   Path to a ttf font used to generate tree
    --fontsize, -s <i>:   Font size: 8-20 (default: 16)
       --color, -c <s>:   Color text and bars: on or off (default: on)
  --symmetrize, -y <s>:   Generate symmetrical, balanced tree: on or off (default: on)
     --autosub, -a <s>:   Put subscript numbers to nodes: on or off (default: off)
         --version, -v:   Print version and exit
            --help, -h:   Show this message


Every branch or leaf of a tree must belong to a node. To create a node, place a label right next to the opening bracket. Arbitrary number of branches can follow with a preceding space.

There are several modes in which the connectors between terminal nodes and their leaves are drawn differently (auto, triangle, bar, and nothing). In auto mode, a triangle is used if the leaf contains one or more spaces inside (i.e. if it’s a phrase), but if it contains no spaces (i.e. if it is just a word), a straight bar will be drawn instead (unless the leaf contains a "^" symbol at the end which makes it a single-word phrase).

You can put a subscript to any node by putting the _ character between the main label and the subscript. For example, NP_TOP will be rendered as NPTOP. Or you can select the “Auto subscript” option so that nodes of the same label will be automatically numbered. (e.g. NP1, NP2)


Bracket notation (auto-subscript-on):

[S [NP RSyntaxTree^][VP [V generates][NP multilingual syntax trees]]]

Resulting PNG

RSyntaxTree generates multilingual syntax trees


For the latest updates and downloads please visit


Yoichiro Hasebe


RSyntaxTree is distributed under the MIT License.

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