glosario

glosario is an open source glossary of terms used in data science that is available online and also as a library in both R and Python. By adding glossary keys to a lesson's metadata, authors can indicate what the lesson teaches, what learners ought to know before they start, and where they can go to find that knowledge. Authors can also use the library's functions to insert consistent hyperlinks for terms and definitions in their lessons in any of several (human) languages.

Lessons

R Markdown and Jupyter notebooks allow authors to place structured metadata in files. We propose the following metadata (written as YAML):

glossary:
  sources:
  - http://some_glossary.org/something/
  language: fr
  requires:
  - aggregation_function
  - call_stack
  defines:
  - closure
  - name_collision

1. The source key is required.
   • It must introduce a list containing at least one URL.
   • Those URLs must resolve to glossaries as described in the next section.
   • Those glossaries are searched in order from first to last to find definitions.
2. The language key is required, and must be a single ISO 639 language code (e.g., fr for French).
3. The keys requires and defines are optional.
   • Either may introduce an empty list.
   • The values under these keys are keys into a shared glossary (discussed in the next section).
4. We expect the terms identified under requires to be used without being defined in this lesson (i.e., the lesson author assumes users already know them).
5. All of the terms identified under defines must be hyperlinked in the lesson.
   • The target of the hyperlink for the term's definition must be GLOSSARY_SITE#glossary_key, where GLOSSARY_SITE is one of the sites listed under the sources key and glossary_key is an exact match for one of the defines keys.

We will provide simple tools to that all of the terms listed in a lesson's metadata are linked correctly in its body. We will also provide shortcuts to make it easy to create correctly-formatted links, so that authors can write things like:

The computer uses a `r link('call stack', 'call_stack')` to keep track of function calls.

Glossaries

Any site where glossary URLs resolve can be used as a glossary. As a working model, this project implements a glossary of terms used in data science and data engineering.

1. The master copy of the glossary lives in glossary.yml. Its format is described below.
2. This file is turned into a single-page GitHub Pages site using Jekyll.
3. It is also turned into a Python package called glosario and an R package with the same name.

A glossary entry is structured like this:

- slug: cran
  en:
    term: "Comprehensive R Archive Network"
    acronym: "CRAN"
    def: >
      A public repository of R [packages](#package).
  ref:
    - base_r
    - tidyverse

• The value associated with the slug key identifies the entry.
  • It must be unique within the glossary.
  • It must be in lower case and use only letters, digits, and the underscore (to be compatible with Jekyll's automatic slug creation).
  • It becomes the fragment identifier in the online version of the glossary.
• The entry may have a ref key. If it is present, its value must be a list of identifiers of related terms in this glossary.
• Every other top-level key must be an ISO 639 language code such as en or fr.
  • Every entry must have at least one such language section.
• Within each language section for each term:
  • The value of term is the term being defined. This key must be present.
  • The key acronym is optional. If present, its value is the acronym for this term.
  • The value of def is the definition. This key must be present, and the value may contain local links to other terms in this glossary (i.e., links starting with #) and/or links to outside sources.

Open issues

1. Should we provide one function for interactive definition lookup that searches keys and terms, a separate function for each, or some kind of keyword arguments to control the scope of search?

2. Should we integrate definition lookup with existing help systems? For example, should define('something') in RStudio put the definition in the help pane (and if so, should it hyperlink to terms that the definition depends on)?

Use Cases

1. Linking to a definition.

   1. Amari writes a lesson in R Markdown that introduces some new terms.
   2. She has defined the language to be Spanish using the glossary/language key in the YAML header, but has not changed any other settings.
   3. She adds an inline code block `r gdef('linear-model', 'Linear models')` to her lesson.
   4. When she knits her document, the inline code block produces the HTML <a href="http://carpentries.org/glossary/es/#linear-model" class="glossary-definition">Linear Models</a>

2. Checking a lesson.

   1. Beatriz has made some changes to a lesson she inherited from Amari, and wants to check that it is still consistent.
   2. She runs a command-line script that:
      1. Reads the R Markdown file.
      2. Extracts the terms under the glossary/defines key.
      3. Searches the body of the document for calls to gdef(...).
      4. Checks that every term listed in glossary/defines is referenced in the document body, and that every term referenced in the document body is mentioned in glossary/defines.

3. Finding lessons.

   1. Amari writes a lesson in R Markdown. She adds the glossary key to its YAML metadata and indicates that the lesson requires the term correlation and defines the term regression.
   2. Beatriz is writing a lesson on linear models. She adds YAML metadata indicating that the lesson requires the term regression.
   3. To find prerequisite lessons she can recommend to her students, Beatriz runs a command-line script that:
      1. Uses rmarkdown::yaml_front_matter(filename) to reads metadata from all of the lessons she has archived.
      2. Lists all of the lessons that state they define the term regression.

4. Summarizing a lesson.

   1. Amari has written a lesson in R Markdown that includes YAML metadata stating that it defines correlation and causation.
   2. She adds a code chunk to the end of her lesson that includes a call to glosario::summarize_terms().
   3. When she knits the document to HTML, this code chunk inserts a definition list dl at that point. Its entries are the definitions of all of the terms listed under the glossary/defines key in the page's YAML header in alphabetical order by term according to the rules for glossary/language.

FAQ

• Why not just link to Wikipedia? We expect that many glossary definitions will do so, but Wikipedia articles are explanations, not definitions.

• YAML is hard for people to edit—why not use something else for the glossary file? Because other formats are just as hard to edit (e.g., JSON) or make one-to-many relationships hard to express (e.g., CSV).

• Why use Jekyll for the online version? It is the default for GitHub Pages.

Credits

• Parrot logo by restocktheshelves.