TerminusDB.WOQL.Path (terminusdb_ex v0.3.3)

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Path pattern parser and structured builders for WOQL path queries.

Supports two modes:

String-compiled parser

TerminusDB.WOQL.Path.parse("friend*{1,3}")
#=> {:times, {:pred, "friend"}, 1, 3}

Grammar: predicate, <inverse, * (star), + (plus), {n} / {n,m} (bounded), | (or), , (sequence), . (any), (...) (grouping).

Structured builders

WOQL.Path.path_star(WOQL.Path.path_pred("friend"))
#=> {:star, {:pred, "friend"}}

Serialization

to_jsonld/1 serializes a Path AST to the WOQL JSON-LD wire format. from_jsonld/1 deserializes back. normalize/1 accepts either a string or an AST tuple and returns an AST tuple.

This module is used internally by WOQL.path/3 and WOQL.path/4 but can also be used directly for building path patterns programmatically.

Summary

Functions

from_jsonld(m)

Deserializes a WOQL JSON-LD path pattern back into a Path AST.

normalize(pattern)

Normalizes a pattern — if it's a string, parses it; if it's already an AST tuple, returns it as-is.

parse(pattern)

Parses a path pattern string into a Path AST.

path_any()

Builds a path "any predicate" node (matches . in the string grammar).

path_inverse(name)

Builds an inverse path — traverses the predicate in reverse direction.

path_or(branches)

Builds a path alternation — any branch may be taken.

path_plus(node)

Builds a path plus — one or more repetitions.

path_pred(name)

Builds a path predicate node for the given predicate name.

path_seq(steps)

Builds a path sequence — each step is traversed in order.

path_star(node)

Builds a path star — zero or more repetitions.

path_times(node, from, to \\ nil)

Builds a path times — from to to repetitions. to may be nil for unbounded.

to_jsonld(arg)

Serializes a Path AST node to the WOQL JSON-LD wire format.

Functions

from_jsonld(m)

@spec from_jsonld(map()) :: tuple()

Deserializes a WOQL JSON-LD path pattern back into a Path AST.

normalize(pattern)

@spec normalize(String.t() | tuple()) :: tuple()

Normalizes a pattern — if it's a string, parses it; if it's already an AST tuple, returns it as-is.

parse(pattern)

@spec parse(String.t()) :: tuple()

Parses a path pattern string into a Path AST.

Examples

iex> TerminusDB.WOQL.Path.parse("friend")
{:pred, "friend"}

iex> TerminusDB.WOQL.Path.parse("friend*")
{:star, {:pred, "friend"}}

iex> TerminusDB.WOQL.Path.parse("<friend")
{:inverse, "friend"}

iex> TerminusDB.WOQL.Path.parse("friend|foe")
{:or, [{:pred, "friend"}, {:pred, "foe"}]}

path_any()

@spec path_any() :: tuple()

Builds a path "any predicate" node (matches . in the string grammar).

path_inverse(name)

@spec path_inverse(String.t()) :: tuple()

Builds an inverse path — traverses the predicate in reverse direction.

path_or(branches)

@spec path_or([tuple()]) :: tuple()

Builds a path alternation — any branch may be taken.

path_plus(node)

@spec path_plus(tuple()) :: tuple()

Builds a path plus — one or more repetitions.

path_pred(name)

@spec path_pred(String.t()) :: tuple()

Builds a path predicate node for the given predicate name.

path_seq(steps)

@spec path_seq([tuple()]) :: tuple()

Builds a path sequence — each step is traversed in order.

path_star(node)

@spec path_star(tuple()) :: tuple()

Builds a path star — zero or more repetitions.

path_times(node, from, to \\ nil)

@spec path_times(tuple(), non_neg_integer(), non_neg_integer() | nil) :: tuple()

Builds a path times — from to to repetitions. to may be nil for unbounded.

to_jsonld(arg)

@spec to_jsonld(tuple()) :: map()

Serializes a Path AST node to the WOQL JSON-LD wire format.