Brassica.SoundChange.Expand

This module implements the process of expansion, from Brassica’s surface syntax to a simpler representation in which all categories, features and autosegments have been inlined. For further

In the surface syntax, each category is represented as a CategorySpec, a description in terms of predefined categories combined with category operations. Expansion converts each one to an Expanded list of graphemes.

Similarly, category definitions are parsed as Directives. Once inlined, these can be replaced with simple GraphemeLists to be used for filtering graphemes.

Main function

expandSoundChanges :: SoundChanges CategorySpec Directive -> Either ExpandError (SoundChanges Expanded GraphemeList)

Expand a set of SoundChanges. Expansion proceeds from beginning to end as follows:

• Rules and filters are expanded by expanding all categories within them (with expand). Graphemes are replaced with categories or autosegments if previously defined as such.
• If a Categories definition block is found, the categories defined within it are expanded and added to (or replace) the list of current categories. The block is replaced with a list of currently defined graphemes.
• If ExtraGraphemes are found, they are added to a list of currently defined graphemes. They are replaced with a GraphemeList only if no categories are defined in the SoundChanges.

data ExpandError

Errors which can be emitted while inlining or expanding category definitions.

Constructors

NotFound String

A category with the given name was not found

InvalidBaseValue

A Lexeme was used as a base value in a feature

InvalidDerivedValue

A Lexeme was used as a derived value in an autosegment

MismatchedLengths

A phonetic feature or FeatureSpec contained a mismatched number of values

Instances

Generic ExpandError

Defined in Brassica.SoundChange.Expand

Associated Types

type Rep ExpandError :: Type -> Type

Methods

from :: ExpandError -> Rep ExpandError x

to :: Rep ExpandError x -> ExpandError

Show ExpandError

Defined in Brassica.SoundChange.Expand

Methods

showsPrec :: Int -> ExpandError -> ShowS

show :: ExpandError -> String

showList :: [ExpandError] -> ShowS

NFData ExpandError

Defined in Brassica.SoundChange.Expand

Methods

rnf :: ExpandError -> ()

type Rep ExpandError

Defined in Brassica.SoundChange.Expand

type Rep ExpandError = D1 ('MetaData "ExpandError" "Brassica.SoundChange.Expand" "brassica-1.0.0-23v7eBGV3gz5i0Q0Z9IDsG" 'False) ((C1 ('MetaCons "NotFound" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 String)) :+: C1 ('MetaCons "InvalidBaseValue" 'PrefixI 'False) (U1 :: Type -> Type)) :+: (C1 ('MetaCons "InvalidDerivedValue" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "MismatchedLengths" 'PrefixI 'False) (U1 :: Type -> Type)))

Expanding individual elements

expand :: Categories -> CategorySpec a -> Either ExpandError (Expanded a)

Given an unexpanded category, return the list of values which it matches.

expandRule :: Categories -> Rule CategorySpec -> Either ExpandError (Rule Expanded)

Expand all categories in a given sound change Rule.

extendCategories

Arguments

:: Categories

-> (Bool, [CategoryDefinition])

The fields of a Categories directive

-> Either ExpandError Categories

Extend a set of previously defined Categories to give the resulting state after a Categories directive.

Categories

type Categories = Map String (Either (Expanded 'AnyPart) AutosegmentDef)

A map from names to the (expanded) categories or autosegments they reference. Used to resolve cross-references between categories.

data AutosegmentDef

Expanding an autosegment from a grapheme requires knowing its feature name, and a set of graphemes cross-cutting that feature. (Note that autoGraphemes includes the originally-written grapheme.)

Constructors

AutosegmentDef

Fields

• autoFeature :: String
• autoGraphemes :: [String]

Instances

Show AutosegmentDef

Defined in Brassica.SoundChange.Expand

Methods

showsPrec :: Int -> AutosegmentDef -> ShowS

show :: AutosegmentDef -> String

showList :: [AutosegmentDef] -> ShowS

Eq AutosegmentDef

Defined in Brassica.SoundChange.Expand

Methods

(==) :: AutosegmentDef -> AutosegmentDef -> Bool

(/=) :: AutosegmentDef -> AutosegmentDef -> Bool

lookup :: String -> Categories -> Maybe (Either (Expanded a) AutosegmentDef)

Lookup a category name in Categories.

values :: Categories -> [[Lexeme Expanded 'AnyPart]]

Returns a list of every value mentioned in a set of Categories