String

Write a string

Given a file named “main.scm” with:

(import (scheme base))

(write-string "Hello, world!")

When I successfully run stak main.scm

Then the stdout should contain exactly “Hello, world!”.

Create a string

Given a file named “main.scm” with:

(import (scheme base))

(write-string (string #\A #\B #\C))

When I successfully run stak main.scm

Then the stdout should contain exactly “ABC”.

Convert a string to a list

Given a file named “main.scm” with:

(import (scheme base))

(for-each write-char (string->list "Hello, world!"))

When I successfully run stak main.scm

Then the stdout should contain exactly “Hello, world!”.

Convert a list to a string

Given a file named “main.scm” with:

(import (scheme base))

(write-string (list->string (string->list "Hello, world!")))

When I successfully run stak main.scm

Then the stdout should contain exactly “Hello, world!”.

Append strings

Given a file named “main.scm” with:

(import (scheme base))

(write-string (string-append <values>))

When I successfully run stak main.scm

Then the stdout should contain exactly “<output>”.

Examples

values	output
""
"foo”	foo
”app” “le”	apple
”dis” “cov” “ery”	discovery

Get a character in a string

Given a file named “main.scm” with:

(import (scheme base))

(write-char (string-ref "<string>" <index>))

When I successfully run stak main.scm

Then the stdout should contain exactly “<output>”.

Examples

string	index	output
a	0	a
ab	0	a
ab	1	b
abc	0	a
abc	1	b
abc	2	c

Set a character in a string

Given a file named “main.scm” with:

(import (scheme base))

(define xs (string-copy "aaa"))

(string-set! xs <index> #\<character>)

(write-u8 (if (equal? xs "<output>") 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Examples

index	character	output
0	b	baa
1	b	aba
2	b	aab
0	a	aaa

index	character	output
1	😄	a😄a

Get a length of a string

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (= (string-length "<value>") <length>) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Examples

value	length
	0
a	1
aa	2
aaa	3

Get a sub-string

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (equal? (substring "<value>" <start> <end>) "<output>") 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Examples

value	start	end	output
	0	0
a	0	0
a	0	1	a
ab	0	0
ab	0	1	a
ab	1	2	b
ab	0	2	ab
abc	0	0
abc	0	1	a
abc	1	2	b
abc	2	3	c
abc	0	2	ab
abc	1	3	bc
abc	0	3	abc

Get a length of a string

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (= (string-length "<value>") <length>) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Examples

value	length
	0
a	1
aa	2
aaa	3

Copy a string in place

Given a file named “main.scm” with:

(import (scheme base))

(define xs (string-copy "<to>"))

(string-copy! xs <at> "<from>" <start> <end>)

(write-u8 (if (equal? xs "<output>") 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Examples

to	at	from	start	end	output
A	0				A
ABC	0	DEF			DEF
ABC	1	DE			ADE
ABC	2	D			ABD
ABCDE	1	FGH			AFGHE
ABCD	1	EFGH	1		AFGH
ABCD	1	EFGH	1	3	AFGD

Make a string

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (= (string-length (make-string <length>)) <length>) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Examples

length
0
1
2
3

Make a string with a character

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (equal? (make-string <length> <character>) "<output>") 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Examples

length	character	output
0	#\A
1	#\A	A
2	#\A	AA
3	#\A	AAA
0	#\B
1	#\B	B
2	#\B	BB
3	#\B	BBB

Iterate over a string

Given a file named “main.scm” with:

(import (scheme base))

(string-for-each write-char "ABC")

When I successfully run stak main.scm

Then the stdout should contain exactly “ABC”.

Map a function to a string

Given a file named “main.scm” with:

(import (scheme base))

(write-u8
  (if (equal? (string-map (lambda (x) (integer->char (+ 1 (char->integer x)))) "ABC") "BCD")
    65
    66))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Check string equality

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (string=? "<value>" "<value>") 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Examples

value
a
ab
abc

Check string inequality

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (string=? "<left>" "<right>") 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “B”.

Examples

left	right
	a
a
a	b
a	ab
ab	a
aa	ab
aa	aaa
aaa	aa
aaa	aab
aab	aaa

Compare strings

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (<procedure> <strings>) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “<output>”.

Examples

procedure	strings	output
string<?	"" ""	B
string<?	"" “a”	A
string<?	“a” “b”	A
string<?	“a” “b” “c”	A
string<?	“a” “aa”	A
string<?	“aa” “aa”	B
string<?	“aa” “ab”	A
string<?	“aa” “aaa”	A
string<?	“aaa” “aab”	A
string>?	"" ""	B
string>?	“a” ""	A
string>?	“a” “a”	B
string>?	“b” “a”	A
string>?	“c” “b” “a”	A
string>?	“aa” “a”	A
string>?	“aa” “aa”	B
string>?	“ab” “aa”	A
string>?	“ba” “aa”	A
string>?	“ba” “ab”	A
string<=?	“aa” “aa”	A
string<=?	“aa” “ab”	A
string<=?	“ab” “aa”	B
string<=?	“aa” “aa” “ab”	A
string>=?	“aa” “aa”	A
string>=?	“aa” “ab”	B
string>=?	“ab” “aa”	A
string>=?	“ab” “aa” “aa”	A

Compare strings ignoring letter cases

Given a file named “main.scm” with:

(import (scheme base) (scheme char))

(write-u8 (if (<procedure> <strings>) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “<output>”.

Examples

procedure	strings	output
string-ci<?	"" ""	B
string-ci<?	"" “a”	A
string-ci<?	“a” “B”	A
string-ci<?	“a” “B” “C”	A
string-ci<?	“a” “AA”	A
string-ci<?	”AA” “aa”	B
string-ci<?	“aa” “AB”	A
string-ci<?	“aa” “AAA”	A
string-ci<?	“aaa” “AAB”	A
string-ci>?	"" ""	B
string-ci>?	“a” ""	A
string-ci>?	”A” “a”	B
string-ci>?	”B” “a”	A
string-ci>?	”C” “b” “a”	A
string-ci>?	”AA” “a”	A
string-ci>?	“aa” “AA”	B
string-ci>?	”AB” “aa”	A
string-ci>?	”BA” “aa”	A
string-ci>?	”BA” “ab”	A
string-ci<=?	“aa” “AA”	A
string-ci<=?	“aa” “AB”	A
string-ci<=?	”AB” “aa”	B
string-ci<=?	“aa” “AA” “AB”	A
string-ci>=?	”AA” “aa”	A
string-ci>=?	“aa” “AB”	B
string-ci>=?	”AB” “aa”	A
string-ci>=?	”AB” “aa” “aa”	A

Convert a vector to a string

Given a file named “main.scm” with:

(import (scheme base))

(write-string (vector->string #(<characters>) <range>))

When I successfully run stak main.scm

Then the stdout should contain exactly “<output>”.

Examples

characters	range	output
#\A		A
#\A #\B #\C		ABC
#\A #\B #\C	0	ABC
#\A #\B #\C	0 2	AB
#\A #\B #\C	1 3	BC
#\A #\B #\C	1 2	B

Convert a vector to a string

Given a file named “main.scm” with:

(import (scheme base))

(write-u8 (if (equal? (string->vector "<string>" <range>) #(<characters>)) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Examples

string	range	characters
A		#\A
ABC		#\A #\B #\C
ABC	0	#\A #\B #\C
ABC	0 2	#\A #\B
ABC	1 3	#\B #\C
ABC	1 2	#\B

Convert a string to a byte vector

Given a file named “main.scm” with:

(import (scheme base))

(define xs "<string>")

(write-u8 (if (equal? (utf8->string (string->utf8 xs)) xs) 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Examples

string
A
ABC
Aあ😄

Convert a string case

Given a file named “main.scm” with:

(import (scheme base) (scheme char))

(write-u8 (if (equal? (<predicate> "<input>") "<output>") 65 66))

When I successfully run stak main.scm

Then the stdout should contain exactly “A”.

Examples

predicate	input	output
string-downcase	Ab	ab
string-foldcase	Ab	ab
string-upcase	Ab	AB

Fill a string

Given a file named “main.scm” with:

(import (scheme base))

(define xs (string-copy "<string>"))

(string-fill! xs <arguments>)

(write-string xs)

When I successfully run stak main.scm

Then the stdout should contain exactly “<output>”.

Examples

string	arguments	output
A	#\a	a
AB	#\a 0	aa
AB	#\a 1	Aa
ABC	#\a	aaa
ABCD	#\a 1 3	AaaD