Safe Haskell | None |
---|
- data Duration
- data Size
- data PrecBuilder = PrecBuilder Int Builder
- parentheses :: Int -> ((PrecBuilder -> Builder) -> Builder) -> PrecBuilder
- class SearchBuilder e where
- searchBuilder :: e -> PrecBuilder
- class SyntaxBuilder f where
- syntaxBuilder :: f PrecBuilder -> PrecBuilder
- class DisjunctF f where
- disjunctF :: e -> e -> f e
- class Disjunct e where
- (\/) :: e -> e -> e
- class ConjunctF f where
- conjunctF :: e -> e -> f e
- class Conjunct e where
- (/\) :: e -> e -> e
- class ComplementF f where
- complementF :: e -> f e
- class Complement e where
- notB :: e -> e
- andB :: Conjunct e => [e] -> e
- orB :: Conjunct e => [e] -> e
- data Term t
- data BooleanF e
- type BooleanM = Free BooleanF
- type Simple = BooleanM (Term Text)
Units
Search expression construction
data PrecBuilder Source
Builder
with precedence, though ambiguous associativity.
(But that's okay because Google doesn't mind which way you lean.)
Note that at Google OR
binds tighter than conjunction, which is flipped
in contrast to everywhere else. We take the analogous Haskell fixities
when building search expressions:
- 11: atomic tokens or parenthesised expressions
- 10: complementation, search operators (cf. Haskell prefix application)
- 3: disjunction (
OR
or|
) - 2: conjunction (by juxtaposition)
parentheses :: Int -> ((PrecBuilder -> Builder) -> Builder) -> PrecBuilderSource
Give me the precedence of the piece of syntax you're building, and I'll give you a function that parenthesise any sub-expressions when necessary.
class SearchBuilder e whereSource
Render a search expression using Google search syntax.
searchBuilder :: e -> PrecBuilderSource
SearchBuilder Text | |
SearchBuilder MailOp | |
SearchBuilder a => SearchBuilder (Term a) | |
(Functor f, SearchBuilder a, SyntaxBuilder f) => SearchBuilder (Free f a) |
|
class SyntaxBuilder f whereSource
Higher-order version of SearchBuilder
.
Generalised Boolean operators
Primitive Terms
Fuzzy
terms are grouped with parentheses (if necessary), while
Exact
terms are always “double-quoted”. The IsString
instance
defaults to Fuzzy
, so just writing "literal string" ∷
is acceptable.
Term
Text
Functor Term | |
SyntaxBuilder Term | |
Show t => Show (Term t) | |
IsString t => IsString (Term t) | |
SearchBuilder a => SearchBuilder (Term a) |
Boolean expressions
The shape of Boolean expressions.