datalog.parser.pull — io.replikativ/datalog-parser 0.2.25

IPullSpecComponent clj/s protocol

-as-spec clj/s

(-as-spec this)

parse-pattern clj/s

(parse-pattern pattern)

Parse an EDN pull pattern into a tree of records using the following grammar:

pattern             = [attr-spec+]
attr-spec           = attr-name | wildcard | map-spec | attr-expr
attr-name           = an edn keyword that names an attr
wildcard            = "*" or '*'
map-spec            = { ((attr-name | attr-expr) (pattern | recursion-limit))+ }
attr-expr           = attr-with-opts | legacy-attr-expr
attr-with-opts      = [attr-name attr-option+]
attr-option         = :as any-value | :limit (positive-number | nil) | :default any-value
recursion-limit     = positive-number | '...'
legacy-attr-expr    = legacy-limit-expr | legacy-default-expr
legacy-limit-expr   = [("limit" | 'limit') attr-name (positive-number | nil)]
legacy-default-expr = [("default" | 'default') attr-name any-value]

parse-pull clj/s

(parse-pull pattern)

Parse EDN pull pattern specification (see parse-pattern), and convert the resulting tree into a PullSpec instance (see pattern->spec). Throws an error if the supplied pattern cannot be parsed.

pattern->spec clj/s

(pattern->spec pattern)

Convert a parsed tree of pull pattern records into a PullSpec instance, a record type containing two keys:

• :wildcard? - a boolean indicating if the pattern contains a wildcard.
• :attrs - a map of attribute specifications.

The attribute specification map consists of keys which will become the keys in the result map, and values which are themselves maps describing the attribute:

• :attr (required) - The attr name to pull; for reverse attributes this will be the normalized attribute name.
• :as (optional) - Alias, any
• :limit (optional) - If present, specifies a custom limit for this attribute; Either nil, indicating no limit, or a positive integer.
• :default (optional) - If present, specifies a default value for this attribute
• :recursion (optional) - If present, specifies a recursion limit for this attribute; Either nil, indicating no limit, or a positive integer.
• :subpattern (optional) - If present, specifies a sub PullSpec instance to be applied to entities matched by this attribute.