Text.Replace

Performing replacement

replaceWithList

Arguments

:: Foldable f

=> f Replace

List of replacement rules

-> String

Input string

-> String

Result after performing replacements on the input string

Apply a list of replacement rules to a string. The search for strings to replace is performed left-to-right, preferring longer matches to shorter ones.

Internally, the list will be converted to a ReplaceMap using listToMap. If the list contains more than one replacement for the same search string, the last mapping is used, and earlier mappings are ignored.

If you are going to be applying the same list of rules to multiple input strings, you should first convert the list to a Trie using listToTrie and then use replaceWithTrie instead.

replaceWithMap

Arguments

:: ReplaceMap

Map of replacement rules

-> String

Input string

-> String

Result after performing replacements on the input string

Apply a map of replacement rules to a string. The search for strings to replace is performed left-to-right, preferring longer matches to shorter ones.

If you are going to be applying the same list of rules to multiple input strings, you should first convert the Map to a Trie using mapToTrie and then use replaceWithTrie instead.

replaceWithTrie

Arguments

:: Trie

Map of replacement rules, represented as a trie

-> String

Input string

-> String

Result after performing replacements on the input string

Apply a trie of replacement rules to a string. The search for strings to replace is performed left-to-right, preferring longer matches to shorter ones.

To construct a Trie, you may use listToTrie or mapToTrie.

Specifying replacements

data Replace

A replacement rule.

Replace "abc" "xyz"

means

When you encounter the string abc in the input text, replace it with xyz.

The first argument must be a non-empty string, because there is no sensible way to interpret "replace all occurrences of the empty string."

Constructors

Replace

Fields

• replaceFrom :: String'

  A string we're looking for

• replaceTo :: String

  A string we're replacing it with

Instances

Eq Replace

Methods

(==) :: Replace -> Replace -> Bool

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

Show Replace

Methods

showsPrec :: Int -> Replace -> ShowS

show :: Replace -> String

showList :: [Replace] -> ShowS

type ReplaceMap = Map String' String

A map where the keys are strings we're looking for, and the values are strings with which we're replacing a key that we find.

You may use listToMap to construct a ReplaceMap from a list of replacement rules, and you may use mapToAscList to convert back to a list.

listToMap :: Foldable f => f Replace -> ReplaceMap

Construct a ReplaceMap from a list of replacement rules.

If the list contains more than one replacement for the same search string, the last mapping is used, and earlier mappings are ignored.

mapToAscList :: ReplaceMap -> [Replace]

Convert a replacement map to a list of replacement rules. The rules in the list will be sorted according to their replaceFrom field in ascending order.

Replacements in trie structure

type Trie = Map Char Trie'

A representation of a ReplaceMap designed for efficient lookups when we perform the replacements in replaceWithTrie.

You may construct a Trie using listToTrie or mapToTrie.

data Trie'

A variant of Trie which may contain a value at the root of the tree.

Constructors

Trie'

Fields

• trieRoot :: Maybe String
• trieBranches :: Trie

Instances

Eq Trie'

Methods

(==) :: Trie' -> Trie' -> Bool

(/=) :: Trie' -> Trie' -> Bool

Show Trie'

Methods

showsPrec :: Int -> Trie' -> ShowS

show :: Trie' -> String

showList :: [Trie'] -> ShowS

listToTrie :: Foldable f => f Replace -> Trie

Convert a list of replacement rules to a trie, which is used to efficiently implement replaceWithTrie.

If the list contains more than one replacement for the same search string, the last mapping is used, and earlier mappings are ignored.

ascListToTrie

Arguments

:: Foldable f

=> f Replace

This list must be sorted according to the replaceFrom field in ascending order

🌶️ Warning: this precondition is not checked

-> Trie

Convert a list of replacement rules to a Trie, where the rules must be sorted in ascending order by the replaceFrom field.

🌶️ Warning: this precondition is not checked. If you are not sure, it is safer to use listToTrie instead.

mapToTrie :: ReplaceMap -> Trie

Convert a replacement map to a trie, which is used to efficiently implement replaceWithTrie.

drawTrie :: Trie -> String

Draws a text diagram of a trie; useful for debugging.

Non-empty string

newtype String'

Non-empty string.

Constructors

String' (NonEmpty Char)

Instances

Eq String'

Methods

(==) :: String' -> String' -> Bool

(/=) :: String' -> String' -> Bool

Ord String'

Methods

compare :: String' -> String' -> Ordering

(<) :: String' -> String' -> Bool

(<=) :: String' -> String' -> Bool

(>) :: String' -> String' -> Bool

(>=) :: String' -> String' -> Bool

max :: String' -> String' -> String'

min :: String' -> String' -> String'

Show String'

Methods

showsPrec :: Int -> String' -> ShowS

show :: String' -> String

showList :: [String'] -> ShowS

IsString String'

fromString = string'fromString

🌶️ Warning: (fromString "" :: String') = ⊥

Methods

fromString :: String -> String'

string'fromString :: String -> String'

Convert an ordinary String to a non-empty String'.

🌶️ Warning: string'fromString "" = ⊥

string'head :: String' -> Char

The first character of a non-empty string.

string'tail :: String' -> String

All characters of a non-empty string except the first.