Data.PrimitiveArray.Index.Subword

Index structure for context-free grammars on strings. A Subword captures a pair (i,j) with i<=j.

Documentation

newtype Subword

A subword wraps a pair of Int indices i,j with i<=j.

Subwords always yield the upper-triangular part of a rect-angular array. This gives the quite curious effect that (0,N) points to the ``largest'' index, while (0,0) ... (1,1) ... (k,k) ... (N,N) point to the smallest. We do, however, use (0,0) as the smallest as (0,k) gives successively smaller upper triangular parts.

Constructors

Subword

Fields

fromSubword :: Int :. Int

Instances

Eq Subword

Ord Subword

Read Subword

Show Subword

Generic Subword

Arbitrary Subword

ToJSON Subword

FromJSON Subword

Binary Subword

Serialize Subword

NFData Subword

Unbox Subword

IndexStream Subword

Index Subword

Vector Vector Subword

MVector MVector Subword

IndexStream z => IndexStream ((:.) z Subword)

type Rep Subword

data Vector Subword = V_Subword (Vector (Int, Int))

data MVector s0 Subword = MV_Subword (MVector s (Int, Int))

subword :: Int -> Int -> Subword

triangularNumber :: Int -> Int

triangular numbers

A000217

upperTri :: Subword -> Int

Size of an upper triangle starting at i and ending at j. "(0,N)" what be the normal thing to use.

subwordIndex :: Subword -> Subword -> Int

Subword indexing. Given the longest subword and the current subword, calculate a linear index "[0,..]". "(l,n)" in this case means "l"ower bound, length "n". And "(i,j)" is the normal index.

TODO probably doesn't work right with non-zero base ?!

subwordFromIndex :: Subword -> Int -> Subword