Hrbrt (Human-Readable BRanching Text) is a file format which expresses a directed graph of text nodes linked by choices, similar to a flow chart. Potential uses include decision trees, questionnaires, and videogame dialogue scripts.
Inspired by Markdown's philosophy, Hrbrt is machine-parsable yet perfectly human-readable. The lack of markup and other syntactic clutter in Hrbrt's syntax makes it easily understandable to non-technical users and convenient to author using any basic text editor.
hrbrt is a command line program (or python module) for parsing files in Hrbrt format. It can convert Hrbrt to other formats or "run" a file using command line or GUI-based prompts.
hrbrt requires Python 3.6 or above, and optionally the Tkinter python module to use the GUI option. Tkinter is part of Python's standard library and is likely to come installed with it, but some distributions do package it separately.
The easiest way to install hrbrt is via pip. Pip can download and install hrbrt directly from the Github project as follows:
pip install git+https://github.com/frimkron/hrbrt#egg=hrbrt
Alternatively you can obtain the source code yourself from Github and run the
setup.py Python script:
hrbrt [OPTIONS] FILE
python -m hrbrt [OPTIONS] FILE
The Hrbrt file to read. Use
- to read from standard input.
File to write output to. Use
- to write to standard output. If input file
is specified, output file defaults to
<infile>.out.<ext> using the name of
the input file and the appropriate file extension for the output format. If no
input file is specified, defaults to standard output.
: Show usage information and exit
: Output the result to
- to write to standard output.
--tofmt isn't also specified, the output format is inferred from the file
extension, or Hrbrt by default.
: Output the result using the given format. One of
--output isn't also specified, output is written to
FILE is the input filename and
EXT is the format's
file extension or, if reading from standard input, output is written to standard
: Run the document interactively in the specified mode.
cli for command
line mode, or
gui for a basic graphical wizard mode. The
requires the TKinter python module.
Validate the file foobar.hb and report errors
$ hrbrt foobar.hb Section "first" has no choice blocks and so cannot reach end of document
Convert questionnaire.hb to Markdown format
$ hrbrt -o questionnaire.md questionnaire.hb
Convert dialogue.hb to XML and write to standard out
$ hrbrt -t xml -o - dialogue.hb <?xml version="1.0" ?> <document> <section> <text>Nice hat!</text> </section> </document>
Read Hrbrt data from standard input, run using a GUI and output to foo.js in JSON format
$ hrbrt -r gui -o foo.js - ::  Yes :  No
As a Python Package
hrbrt Python package can be imported and used to parse Hrbrt in other
Python code. The
hrbrt.io.HrbrtIO class reads Hrbrt data from a text stream
and produces a
hrbrt.parse.Document object representing the parse tree.
See the usage example below:
>>> from io import StringIO >>> from hrbrt.io import HrbrtIO >>> >>> # A minimal Hrbrt document ... data = ":: Test\n" >>> >>> # Create a simple string stream. ... # Could read from a file stream instead ... stream = StringIO(data) >>> >>> # Parse the data stream ... document = HrbrtIO.read(stream) >>> >>> # Read data from the resulting parse tree ... print(document.sections.items.text) Test >>>
How to Read Hrbrt
A document in Hrbrt format can be parsed by the recipient's machine and presented to them interactively, or the recipient can edit and return the raw text document.
In either case, the recipient begins reading at the start of the document. When
they encounter a set of choices, they mark their selection and read the
response text beside it. If the response includes a
GO TO statement, the
reader jumps to that section and continues from there, otherwise the reader
continues reading as normal. The reader continues to follow the flow of the
document until they reach the end.
A recipient reading the raw Hrbrt text may mark their selection at each set of options by inserting character data in the corresponding box (typically an 'X' or '#'). They may also add feedback to the document by adding new lines of text or writing in the existing blank lines.
Below is an example of Hrbrt syntax:
:: Hi there. %% Please fill in my questionnaire! :: What would you say : is your favourite animal? :: [ ] Cat -- GO TO cats : [ ] Dog -- GO TO other : [ ] Turkey -- GO TO other === Cats === :: What is your favourite breed of cat? :: [ ] Burmese : [ ] Siamese : [ ] Persian : [ ] Other :: What do you like most about cats? :: [ ] Their ears -- GO TO end : [ ] Their noses -- GO TO end : [ ] Their paws -- GO TO end : [ ] Their fur -- GO TO end === Other === :: Are you sure you don't like : CATS more? :: [ ] Yes -- GO TO end : [ ] No -- Your finger slipped. I see. : GO TO cats === End === :: Thanks for your input!
Sections serve to split up the document and provide reference points to which the user can be directed as they traverse the document. (See explanation of "go-to" statements in the chapter "Choice Responses").
Each section contains one or more blocks of content. These may be any combination of text, instruction or choice blocks (see subsequent chapters for details).
The first section of the document is where the user begins reading, and has no heading. Each subsequent section is indicated by a heading with two or more equals signs on each side. The section heading defines the section's name, which is case-insensitive. Section names must only contain letters, numbers, underscores, hyphens or spaces. All content below this heading, down to the next heading, is contained within the section.
=== My Section ===
Text and Recipient's Feedback
Blocks of regular text can be added to the document by starting the first line of the block with a double colon, and each subsequent line with a single colon. A Hrbrt viewing tool will typically present separate text blocks to the user one at a time.
Lines without the preceding colons are assumed to be part of the recipient's feedback. It is assumed that if the recipient leaves feedback in the document, they will omit the colon from the start.
:: This is part of the : document text that : the sender wrote But this is the recipient's feedback
When the document is parsed, recipient feedback is included in the output. Feedback within a choice block (see "Choices" chapter) is grouped together and attached to the block, and other feedback is grouped together and attached to the section.
Instruction blocks are not presented to the user when parsed by a program such as a visual Hrbrt reader. They are intended for providing instructions to users reading the raw file text only. The first line of an instruction block starts with a double percent sign, and each subsequent line with a single percent sign.
%% Please fill in this document % and send it back as soon as % possible
Blocks of choices are used to present the user with options from which they can
make a single selection. Users Reading the raw Hrbrt text indicate their
selection by writing something inside the box beside it. This is typically an
# character, but may contain any single-line content other than
Each choice of the block goes on its own line. The first choice starts with a
double colon, and each subsequent choice starts with a single colon. Each
option then consists of a pair of square brackets
 followed by the option
description. The description may run onto multiple lines, each starting with a
::  Animal :  Some kind : of Mineral :  Vegetable
A choice block may not immediately follow another choice block. They must be separated, using a text block for example.
Each choice may optionally be followed by response text. This is
separated from the choice description by a pair of hyphens
--. The response
text gives feedback and further instructions to the recipient on selection of
A choice response may optionally be followed by a go-to statement. This
consists of the words
GO TO in uppercase, followed by a section name, and
optional trailing punctuation. The section names are case-insensitive.
The go-to statement instructs the recipient or viewing tool as to which section
to jump to next.
The response and go-to statement may flow onto multiple lines, each starting with a colon.
::  Animal -- Good choice! GO TO my section :  Mineral -- OK. GO TO some section. :  Vegetable -- Not bad, but I : think you could : have chosen better. : GO TO end
All lines in the document may optionally be prefixed with
> markers, as would
typically be added by an email client. The
> markers themselves are ignored,
but the following line content is still parsed. This allows recipients to reply
directly to a document sent by email and it still be parsable.
Section Flow Rules
A valid Hrbrt document must allow the user to reach the end of the document's final section. Dead ends and infinite loops are not allowed.
Before reaching the end of a section (other than the final section) the user must be explicitly directed to a different section by a go-to statement. In other words, a document is not valid if the user can "fall through" to the end of a section.
For example, the following is not allowed:
::  Option A -- GO TO my section :  Option B == My Section == ...
A choice block may not immediately follow another choice block (for readability reasons). They must be separated by another block, such as a text block.
Hrbrt Formal Definition
Credits and Licence
- Author: Mark Frimston
- Email: email@example.com
- Homepage: http://markfrimston.co.uk
- Project page: https://github.com/frimkron/hrbrt
hrbrt tool is released under the MIT licence. For the full text of
this licence, see