Linguistic Type Data-Base (ltdb)

The Linguistic Type Database (LTDB, née Lextype DB), describes types and rules of a DELPH-IN grammar with frequency information from the treebank. Lexical types can be seen as detailed parts-of-speech. Information about the types are constructed from the linguists documentation in the grammar, a kind of literate programming.

Development setup

uv sync --extra dev   # installs app + ruff
uv run ruff check .   # lint
uv run ruff format .  # format

Quick Start

A separate database is made for each grammar. The description for the grammar is read from the METADATA, a single project may have multiple grammars.

Compile a database with:

$ python scripts/grm2db.py --outdir web/db path/to/METADATA

Add --ace to also compile an ACE .dat file (required for the parse demo):

$ python scripts/grm2db.py --outdir web/db --ace path/to/METADATA

Run python scripts/setup_ace.py first to download the ACE binary if it is not already on your PATH.

Options:

• --checkgrm only includes treebanks made by the same grammar version
• --outdir output directory (a temporary directory is used otherwise)
• --ace also compile a .dat file for the parse/generate demo
• --ace-bin path to ACE binary (default: search PATH then etc/ace-*/ace)

The grammars are read by a web application written using Flask. See Install.md for deployment instructions.

METADATA best practices

Each grammar needs a TOML-formatted METADATA file. The fields recognised by ltdb are:

Field	Type	Required	Description
GRAMMAR_NAME	string	yes	Full grammar name shown in the UI
SHORT_GRAMMAR_NAME	string	yes	Short name used for the database filename
WEBSITE	string		Grammar project homepage URL
LICENSE	string		License name or URL
ACE_CONFIG_FILE	string	yes	Path to the ACE config file (relative to METADATA)
TSDB_ROOTS	list of strings		Directories containing treebank profiles (default: ["tsdb/gold/"])
PROFILES	list of strings		Specific profile names to include (default: all found under TSDB_ROOTS)
EXAMPLES	list of strings		Example sentences shown in the parse demo and used to seed input history

The EXAMPLES field is especially useful for the demo page: sentences are pre-loaded into the input box and the browser history list, so users can try the grammar immediately.

Example METADATA:

GRAMMAR_NAME = "English Resource Grammar"
SHORT_GRAMMAR_NAME = "erg"
WEBSITE = "https://delph-in.github.io/docs/erg/"
LICENSE = "MIT"
ACE_CONFIG_FILE = "ace/config.tdl"
TSDB_ROOTS = ["tsdb/gold/"]
EXAMPLES = [
  "Abrams hired two competent programmers.",
  "The dog chases the cat.",
  "Kim arrived.",
]

URL grammar selection

Any page accepts a ?grm= query parameter to select a grammar directly, without going through the home page form:

/ltdb?grm=yue_2023.01.10          → selects grammar, redirects to grammar page
/ltdb/demo?grm=yue_2023.01.10     → opens demo with that grammar active
/ltdb/grammar.html?grm=erg_2025   → opens grammar summary for the ERG
/ltdb/type/noun?grm=erg_2025      → opens type page with the ERG selected

The .db extension is optional. The grammar name must match the stem of a .db file in web/db/; unrecognised names are silently ignored and the current session grammar is preserved.

Docstring format

TDL docstrings are rendered as Markdown. Standard Markdown formatting (headings, bold, italic, lists, code) is supported. The following ltdb-specific tags are also recognised:

• <ex>text — grammatical example
• <nex>text — ungrammatical example (prefixed ∗)
• <mex>text — marginal example (prefixed ⊛)
• <name lang='xx'>Name</name> — name of the type in language xx

There is more documentation <http://moin.delph-in.net/LkbLtdb>__ at the DELPH-IN Wiki.

Types, instances in the same table, distinguished by status.

+----------+------------------------------------+-------------------+------+ |status |thing | source | end | +==========+====================================+===================+======+ |type |normal type | | | +----------+------------------------------------+-------------------+------+ |lex-type |lexical type |type + in lexicon | _lt | +----------+------------------------------------+-------------------+------+ |lex-entry |lexical entry | | _le |
+----------+------------------------------------+-------------------+------+ |rule |syntactic construction/grammar rule | LKB:*RULES | _c | +----------+------------------------------------+-------------------+------+ |lex-rule | lexical rule | LKB:*LRULES | lr | +----------+------------------------------------+-------------------+------+ |inf-rule |inflectional rule | LKB:*LRULES + | ilr | +----------+------------------------------------+-------------------+------+ | | (inflectional-rule-pid )| | | +----------+------------------------------------+-------------------+------+ | |orth-invariant inflectional rule | | _ilr | +----------+------------------------------------+-------------------+------+ | |orth-changing inflectional rule | | _olr | +----------+------------------------------------+-------------------+------+ | |orth-invariant derivational rule | | _dlr | +----------+------------------------------------+-------------------+------+ | |orth-changing derivation rule | |_odlr | +----------+------------------------------------+-------------------+------+ | |punctuation affixation rule | | _plr | +----------+------------------------------------+-------------------+------+ |root |root | | | +----------+------------------------------------+-------------------+------+

+--------+--------------------------------------+ | Symbol | Explanation | +========+======================================+ | ▲ | Unary, Headed | +--------+--------------------------------------+ | △ | Unary, Non-Headed | +--------+--------------------------------------+ | ◭ | Binary, Left-Headed | +--------+--------------------------------------+ | ◮ | Binary, Right-Headed | +--------+--------------------------------------+ | ◬ | Binary, Non-Headed | +--------+--------------------------------------+