NodeJS version of the ChromeVox speech rule engine. Forked from ChromeVox release 1.31.0
Speech rule engine (SRE) can translate XML expressions into speech strings according to rules that can be specified in a syntax using Xpath expressions. It was originally designed for translation of MathML and MathJax DOM elements for the ChromeVox screen reader. Besides the rules originally designed for the use in ChromeVox, it also has an implemententation of the full set of Mathspeak rules. In addition it contains a library for semantic interpretation and enrichment of MathML expressions.
There are three ways of using this engine:
-
Node Module: Download via npm. This is the easiest way to use the speech rule engine via its Api and is the preferred option if you just want to include it in your project.
-
Standalone Tool: Download via github and build with make. This is useful if you want to use the speech rule engine in batch mode or interactivley to add your own code. Or simply run it with
npx, for example to get all SRE options anywhere without local installation run:npx speech-rule-engine -h -
Browser Library: This gives you the option of loading SRE in a browser and use its full functionality on your webesites.
Install as a node module using npm:
npm install speech-rule-engine
Then import into a running node or a source file using require:
require('speech-rule-engine');
Current API functions are divided into three categories.
| Method | Return Value |
|---|---|
toSpeech(mathml) |
Speech string for the MathML. |
toSemantic(mathml) |
XML representation of the semantic tree for the MathML. |
toJson(mathml) |
The semantic tree in JSON. This method only works in Node, not in browser mode. |
toDescription(mathml) |
The array of auditory description objects of the MathML expression. |
toEnriched(mathml) |
The semantically enriched MathML expression. |
Note that in asynchronous operation mode for these methods to work correctly, it is necessary to ensure that the Engine is ready for processing. See the engineReady flag below.
If the output filename is not provided, output will be written to stdout.
| Method | Return Value |
|---|---|
file.toSpeech(input, output) |
Speech string for the MathML. |
file.toSemantic(input, output) |
XML representation of the semantic tree for the MathML. |
file.toJson(input, output) |
The semantic tree in JSON. This method only works in Node, not in browser mode. |
file.toDescription(input, output) |
The array of auditory description objects of the MathML expression. |
file.toEnriched(input, output) |
The semantically enriched MathML expression. |
It takes a feature vector (an object of option/value pairs) to parameterise the Speech Rule Engine.
setupEngine(options);
Most common options are:
| Option | Value |
|---|---|
| domain | Domain or subject area of speech rules (e.g., mathspeak, emacspeak). |
| style | Style of speech rules (e.g., brief). |
| locale | Language locale in 639-1. Currently available: en, es |
| markup | Set the markup: none, ssml, sable, voicexml, acss |
| walker | A walker to use for interactive exploration: None, Syntax, Semantic, Table |
| semantics | Boolean flag to switch OFF semantic interpretation. Non-semantic rule sets are deprecated. |
Observe that some speech rule domains only make sense with semantics switched on or off and that not every domain implements every style. See also the description of the command line parameters in the next section for more details.
Other options to give more fine grained control of the SRE that are useful during development are:
| Option | Value |
|---|---|
| cache | Boolean flag to switch expression caching during speech generation. Default is true. |
| strict | Boolean flag indicating if only a directly matching rule should be used. I.e., no default rules are used in case a rule is not available for a particular domain, style, etc. Default is false. |
| speech | Depth to which generated speech is stored in attributes during semantic enrichment. Values are none, shallow, deep. Default is none. |
| mode | The running mode for SRE: sync, async, http |
| json | URL where to pull the json speech rule files from. |
| xpath | URL where to pull an xpath library from. This is important for environments not supporting xpath, e.g., IE or Edge. |
| rules | A list of rulesets to use by SRE. This allows to artificially restrict available speech rules, which can be useful for testing and during rule development. Always expects a list, even if only one rule set is supplied! |
For the following methods sre maintains an internal state, hence they are only really useful when running in browser or in a Node REPL. Hence they are not exposed via the command line interface.
| Method | Return Value |
|---|---|
walk(input) |
Speech string for the MathML. |
move(keycode) |
Speech string after the move. Keycodes are numerical strings representing cursor keys, space, enter, etc. |
| Method | Return Value |
|---|---|
pprintXML(string) |
Returns pretty printed version of a serialised XML string. |
version |
Returns SRE's version number. |
engineReady() |
Returns flag indicating that the engine is ready for procssing (i.e., all necessary rule files have been loaded, the engine is done updating, etc.). This is important in asynchronous settings. |
Install dependencies either by running:
npm install
Or install them manually. SRE depends on the following libraries:
google-closure-compiler
google-closure-library
xmldom-sre
wicked-good-xpath
commander
xml-mapping
Depending on your setup you might need to adapt the NODEJS and NODE_MODULES variable in the Makefile. Then simply run
make
This will make both the command line executable and the interactive load script.
bin/sre -i infile -o outfile
As an example run
bin/sre -i resources/samples/sample1.xml -o sample1.txt
Import into a running node process
require('./lib/sre4node.js');
Note, that this will import the full functionality of the speech rule engine in the sre namespace and of the closure library in the goog namespace.
The following is a list of command line options for the speech rule engine.
| Short | Long | Meaning |
|---|---|---|
| -i | --input [name] | Input file [name] |
| -o | --output [name] | Output file [name]. |
| If not given output is printed to stdout. | ||
| -d | --domain [name] | Domain or subject area [name]. |
| This refers to a particular subject type of speech rules or subject area rules are defined for (e.g., mathspeak, physics). | ||
| If no domain parameter is provided, domain default is used. | ||
| -t | --style [name] | Speech style [name]. |
| Selects a particular speech style (e.g., brief). | ||
| If no style parameter is provided, style default is used. | ||
| -c | --locale | Language locale in ISO 639-1. |
| -s | --semantics | Switch on semantics interpretation. |
| Note, that some speech rule domains only make sense with semantics switched on or off. | ||
| -e | --enumerate | Enumerates all available domains and styles. |
| Note that not every style is implemented in every domain. | ||
| -a | --audit | Generate auditory descriptions (JSON format). |
| -j | --json | Generate JSON of semantic tree. |
| -m | --mathml | Generate enriched MathML. |
| -p | --speech | Generate speech output (default). |
| -k | --markup [name] | Generate speech output with markup tags. Currently supported SSML, VoiceXML, Sable, ACSS (as sexpressions for Emacsspeak) |
| -x | --xml | Generate XML of semantic tree. |
| -v | --verbose | Verbose mode. Print additional information, useful for debugging. |
| -l | --log [name] | Log file [name]. Verbose output is redirected to this file. |
| If not given verbose output is printed to stdout. | ||
| -h | --help | output usage information |
| -V | --version | output the version number |
SRE can be used as a browser ready library giving you the option of loading it in a browser and use its full functionality on your webesites.
Build SRE with
make browser
Then include the resulting file sre_browser.js in your website in a script tag
<script src="[URL]/sre_browser.js"></script>The full functionality is now available in the sre namespace. The most
important API functions are also available in SRE.
In addition to programmatically configuring SRE using the setupEngine
method, you can also include a configuration element in a website, that can take the same options as setupEngine.
For example the configuration element
<script type="text/x-sre-config">
{
"json": "https://rawgit.com/zorkow/speech-rule-engine/develop/src/mathmaps",
"xpath": "https://rawgit.com/google/wicked-good-xpath/master/dist/wgxpath.install.js",
"domain": "mathspeak",
"style": "sbrief"
}
</script>will cause SRE to load JSON files from rawgit and for IE or Edge it will also load Google's
wicked good xpath library. In addition the speech rules are set to mathspeak in super brief style.
Make sure the configuration element comes before the script tag loading SRE in your website!
make mathjax
generates a build specific for MathJax in mathjax_sre.js.
SRE can then be configured locally on webpages as described above.
Other make targets useful during development are:
make test
Runs all the tests using Node's assert module. Output is pretty printed to stdout.
make lint
Runs the closure linter tool. To use this option, you need to install the node package
npm install closure-linter-wrapper
To automatically fix some of linting errors run:
make fixjsstyle
Note, that all JavaScript code in this repository is fully linted and compiles error free with respect to the strictest possible closure compiler settings, however, not using the newCheckTypes option.
When creating a pull request, please make sure that your code compiles and is fully linted.
The speech rule engine is published as a node package in fully compiled form, together with the JSON libraries for translating atomic expressions. All relevant files are in the lib subdirectory.
To publish the node package run
npm publish
This first builds the package by executing
make publish
This make command is also useful for local testing of the package.
To generate documentation from the JSDOC, simply run
make docs
This will generate documentation for the source coude and test code in the directories docs/src and docs/tests, respectively.