Definitions for String

This file defines a bunch of functions for the String datatype.

def String.leftpad (n : Nat) (c : Char) (s : String) : String

Pad s : String with repeated occurrences of c : Char until it's of length n. If s is initially larger than n, just return s.

Equations

• String.leftpad n c s = { data := List.leftpad n c s.data }

def String.replicate (n : Nat) (c : Char) : String

Construct the string consisting of n copies of the character c.

Equations

• String.replicate n c = { data := List.replicate n c }

def String.isPrefix : String → String → Prop

s.isPrefix t checks if the string s is a prefix of the string t.

Equations

• String.isPrefix x x = match x, x with | { data := d1 }, { data := d2 } => d1 <+: d2

def String.isSuffix : String → String → Prop

s.isSuffix t checks if the string s is a suffix of the string t.

Equations

• String.isSuffix x x = match x, x with | { data := d1 }, { data := d2 } => d1 <:+ d2

def String.mapTokens (c : Char) (f : String → String) : String → String

String.mapTokens c f s tokenizes s : string on c : char, maps f over each token, and then reassembles the string by intercalating the separator token c over the mapped tokens.

Equations

• String.mapTokens c f = String.intercalate (String.singleton c) ∘ List.map f ∘ fun x => String.split x fun x => decide (x = c)

def String.getRest (s : String) (t : String) : Option String

getRest s t returns some r if s = t ++ r. If t is not a prefix of s, it returns none.

Equations

• String.getRest s t = List.asString <$> List.getRest (String.toList s) (String.toList t)

def String.head (s : String) : Char

Produce the head character from the string s, if s is not empty, otherwise 'A'.

Equations

• String.head s = String.Iterator.curr (String.iter s)